TM
Cortina Systems® LXT973 10/100 Mbps
Dual-Port Fast Ethernet PHY Transceiver
Datasheet
The Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver (LXT973
Transceiver) is an IEEE 802.3 compliant, dual-port, Fast Ethernet PHY transceiver that directly supports
both 100BASE-TX and 10BASE-T applications. Each port provides a Media Independent Interface (MII)
for easy attachment to 10 Mbps and 100 Mbps Media Access Controllers (MACs). The LXT973
Transceiver also provides a Low-Voltage Positive Emitter Coupled Logic (LVPECL) interface per port for
use with 100BASE-FX fiber networks. The LXT973 Transceiver incorporates the auto MDI/MDIX feature,
allowing it to automatically switch twisted-pair inputs and outputs.
The LXT973 Transceiver is an ideal building block for systems that require two Ethernet ports, such as
Internet Protocol (IP) Telephones, Twisted-Pair (TX)-to-Fiber (FX) converter modules, and for telecom
applications, such as Telecom Central Office (TCO) and Customer Premise Equipment (CPE) devices.
The LXT973 Transceiver supports full-duplex operation at both 10 Mbps and 100 Mbps. Its operating
modes can be set using auto-negotiation, parallel detection, or manual control.
Applications
Enterprise switches
IP telephony switches
Storage Area Networks
Multi-port Network Interface Cards (NICs)
Product Features
Dual-port Fast Ethernet PHY
2.5 Voperation
3.3 Voperation I/O compatibility
Low power consumption; 250 mW per port
typical
Full dual-port MII interface with extended
registers
Auto MDI/MDIX switch over capability
Signal Quality Error (SQE) enable/disable
100BASE-FX fiber-optic capability on both ports
Supports both auto-negotiation systems and
legacy systems without auto-negotiation
capability
Support for Next Page
20 MHz Register Access
Configurable via MDIO port or external control
pins
Integrated termination resistors
100-pin Plastic Quad Flat Package (PQFP)
• Commercial (0 C to 70 C ambient)
SLXT973QC Transceiver
EGLXT973QC Transceiver (RoHS Compliant)
• (-40 C to +85 C ambient) (Extended)
SLXT973QE Transceiver
EGLXT973QE Transceiver (RoHS Compliant
249426, Revision 7.0
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Legal Disclaimers
INFORMATION IN THIS DOCUMENT IS PROVIDED IN CONNECTION WITH CORTINA SYSTEMS® PRODUCTS.
NO LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS
GRANTED BY THIS DOCUMENT.
EXCEPT AS PROVIDED IN CORTINA’S TERMS AND CONDITIONS OF SALE OF SUCH PRODUCTS, CORTINA ASSUMES NO
LIABILITY WHATSOEVER, AND CORTINA DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE
AND/OR USE OF CORTINA PRODUCTS, INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A
PARTICULAR PURPOSE, MERCHANTABILITY OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER
INTELLECTUAL PROPERTY RIGHT.
Cortina products are not intended for use in medical, life saving, life sustaining, critical control or safety systems, or in nuclear facility
applications.
CORTINA SYSTEMS®, CORTINA™, and the Cortina Earth Logo are trademarks or registered trademarks of Cortina Systems, Inc. or
its subsidiaries in the US and other countries. Any other product and company names are the trademarks of their respective owners.
Copyright © 2001—2011 Cortina Systems, Inc. All rights reserved.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Contents
Contents
1.0
Pin Assignments and Signal Descriptions ............................................................................... 14
2.0
Signal Descriptions ..................................................................................................................... 18
3.0
Functional Description................................................................................................................ 24
3.1
3.2
3.3
3.4
3.5
3.6
3.7
Introduction ......................................................................................................................... 24
3.1.1 Comprehensive Functionality ................................................................................ 24
Interface Descriptions ......................................................................................................... 24
3.2.1 10/100 Mbps Network Interface............................................................................. 24
3.2.1.1 Twisted-Pair Interface ............................................................................ 25
3.2.1.2 MDI Crossover (MDIX)........................................................................... 26
3.2.1.3 Fiber Interface........................................................................................ 26
MII Operation ...................................................................................................................... 26
3.3.1 MII Clocks .............................................................................................................. 26
3.3.2 Transmit Enable..................................................................................................... 26
3.3.3 Receive Data Valid ................................................................................................ 26
3.3.4 Carrier Sense......................................................................................................... 27
3.3.5 Error Signals .......................................................................................................... 27
3.3.6 Collision ................................................................................................................. 27
3.3.7 Loopback ............................................................................................................... 27
3.3.7.1 Operational Loopback............................................................................ 27
3.3.7.2 Test Loopback ....................................................................................... 27
3.3.8 Configuration Management Interface .................................................................... 28
3.3.8.1 MII Management Interface ..................................................................... 28
3.3.8.2 MII Addressing ....................................................................................... 29
3.3.8.3 Hardware Control Interface.................................................................... 30
Operating Requirements..................................................................................................... 30
3.4.1 Power Requirements ............................................................................................. 30
3.4.2 Clock Requirements .............................................................................................. 30
3.4.2.1 Reference Clock / External Oscillator .................................................... 30
3.4.2.2 MDIO Clock............................................................................................ 31
Initialization ......................................................................................................................... 31
3.5.1 MDIO Control Mode............................................................................................... 31
3.5.2 Hardware Control Mode......................................................................................... 31
3.5.3 Power-Down Mode ................................................................................................ 31
3.5.3.1 Hardware Power-Down.......................................................................... 32
3.5.3.2 Software Power-Down ........................................................................... 32
3.5.4 Reset ..................................................................................................................... 32
3.5.5 Hardware Configuration Settings........................................................................... 32
Link Establishment.............................................................................................................. 33
3.6.1 Auto-Negotiation .................................................................................................... 33
3.6.1.1 Base Page Exchange ............................................................................ 33
3.6.1.2 Next Page Exchange ............................................................................. 34
3.6.1.3 Controlling Auto-Negotiation .................................................................. 34
3.6.1.4 Link Criteria............................................................................................ 34
3.6.1.5 Parallel Detection................................................................................... 34
Network Media/Protocol Support ........................................................................................ 35
3.7.1 10/100 Mbps Network Interface............................................................................. 35
3.7.2 Twisted-Pair Interface............................................................................................ 35
3.7.3 Fiber Interface........................................................................................................ 36
3.7.4 Fault Detection and Reporting ............................................................................... 36
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3.8
3.9
3.10
4.0
Contents
3.7.5 Remote Fault ......................................................................................................... 36
3.7.6 Far End Fault ......................................................................................................... 36
100 Mbps Operation ........................................................................................................... 37
3.8.1 100BASE-X Network Operations........................................................................... 37
3.8.2 100BASE-X Protocol Sublayer Operations............................................................ 37
3.8.3 PCS Sublayer ........................................................................................................ 37
3.8.3.1 Preamble Handling ................................................................................ 38
3.8.3.2 Dribble Bits............................................................................................. 38
3.8.4 PMA Sublayer........................................................................................................ 38
3.8.4.1 Link Failure Override.............................................................................. 38
3.8.4.2 Carrier Sense......................................................................................... 39
3.8.4.3 Twisted-Pair PMD Sublayer................................................................... 39
3.8.4.4 Scrambler/Descrambler ......................................................................... 39
3.8.4.5 Baseline Wander Correction .................................................................. 39
3.8.5 Fiber PMD Sublayer .............................................................................................. 39
3.8.5.1 Far End Fault Indications ....................................................................... 39
10 Mbps Operation ............................................................................................................. 40
3.9.1 Polarity Correction ................................................................................................. 40
3.9.2 Dribble Bits ............................................................................................................ 40
3.9.3 Link Test ................................................................................................................ 40
3.9.4 Link Failure ............................................................................................................ 40
3.9.5 Jabber.................................................................................................................... 41
Monitoring Operations ........................................................................................................ 41
3.10.1 Monitoring Auto-Negotiation .................................................................................. 41
3.10.2 Per-Port LED Driver Functions .............................................................................. 41
Application Information .............................................................................................................. 42
4.1
4.2
4.3
4.4
4.5
Design Recommendations.................................................................................................. 42
4.1.1 General Design Guidelines.................................................................................... 42
4.1.2 Power Supply Filtering........................................................................................... 42
4.1.3 Power and Ground Plane Layout Considerations.................................................. 43
4.1.3.1 Chassis Ground ..................................................................................... 43
4.1.4 MII Terminations .................................................................................................... 43
4.1.5 The Fiber Interface ................................................................................................ 43
4.1.6 Twisted-Pair Interface............................................................................................ 44
4.1.7 Magnetics Information ........................................................................................... 44
Typical Application Circuits................................................................................................. 46
Initialization ......................................................................................................................... 51
MDIO Control Mode............................................................................................................ 51
Manual Control Mode ......................................................................................................... 51
5.0
Configuration ............................................................................................................................... 53
6.0
Auto Negotiation.......................................................................................................................... 55
7.0
Auto-MDI/MDIX............................................................................................................................. 56
8.0
100 Mbps Operation .................................................................................................................... 57
8.1
Displaying Symbol Errors ................................................................................................... 57
8.1.1 Scrambler Seeding ................................................................................................ 58
8.1.2 Scrambler Bypass.................................................................................................. 58
8.1.3 100BASE-T Link Failure Criteria and Override...................................................... 58
8.1.4 Baseline Wander Correction.................................................................................. 58
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8.1.5
9.0
Contents
Programmable Tx Slew Rate................................................................................. 58
Fiber Interface.............................................................................................................................. 60
10.0 10 Mbps Operation ...................................................................................................................... 61
10.1
10.2
10.3
10.4
10.5
10.6
10.7
10.8
Link Test ............................................................................................................................. 61
10Base-T Link Failure Criteria and Override ...................................................................... 61
SQE (Heartbeat) ................................................................................................................. 61
Jabber................................................................................................................................. 61
Polarity Correction .............................................................................................................. 61
Dribble Bits ......................................................................................................................... 62
Transmit Polarity Control .................................................................................................... 62
PHY Address ...................................................................................................................... 62
11.0 Clock Generation......................................................................................................................... 63
11.1
External Oscillator............................................................................................................... 63
12.0 Register Definitions..................................................................................................................... 65
13.0 Magnetics Information ................................................................................................................ 75
14.0 Test Specifications...................................................................................................................... 76
15.0 Timing Diagrams ......................................................................................................................... 81
16.0 Mechanical Specifications.......................................................................................................... 92
16.1
Top Label Marking .............................................................................................................. 92
17.0 Product Ordering Information .................................................................................................... 95
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Figures
Figures
1
Block diagram................................................................................................................................ 13
2
Pin Assignments............................................................................................................................ 14
3
Interfaces....................................................................................................................................... 25
4
Loopback Paths ............................................................................................................................ 28
5
Management Interface Read Frame Structure .............................................................................. 29
6
Management Interface Write Frame Structure .............................................................................. 29
7
Port Address Scheme ................................................................................................................... 30
8
Auto-Negotiation Operation .......................................................................................................... 35
9
100BASE-X Frame Format ........................................................................................................... 37
10
Protocol Sublayers ....................................................................................................................... 38
11
Typical LED Implementation ......................................................................................................... 41
12
Power and Ground Supply Connections ...................................................................................... 46
13
Typical Twisted-Pair Interface ...................................................................................................... 47
14
Recommended LXT973 Transceiver Transceiver-to-3.3 V Fiber Transceiver Interface Circuitry . 48
15
Recommended LXT973 Transceiver-to-5 V Fiber Transceiver Interface Circuitry........................ 49
16
ON Semiconductor* Triple PECL-to-LVPECL Logic Translator .................................................... 50
17
Typical MII Interface ..................................................................................................................... 50
18
Initialization Sequence................................................................................................................... 51
19
100BASE-TX Frame Format ......................................................................................................... 57
20
100BASE-TX Data Path ................................................................................................................ 57
21
100BASE-TX Reception with no Errors......................................................................................... 58
22
100BASE-TX Reception with Invalid Symbol ................................................................................ 59
23
100BASE-TX Transmission with no Errors.................................................................................... 59
24
100BASE-TX Transmission with Collision..................................................................................... 59
25
MII 10BASE-T DTE Mode Auto-Negotiation.................................................................................. 63
26
100BASE-T DTE Mode Auto-Negotiation...................................................................................... 63
27
Link Down Clock Transition ........................................................................................................... 64
28
PHY Identifier Bit Mapping ............................................................................................................ 68
29
100BASE-TX Transmit Timing - 4B Mode..................................................................................... 81
30
100BASE-TX Receive Timing - 4B Mode...................................................................................... 82
31
100BASE-FX Transmit Timing ...................................................................................................... 83
32
100BASE-FX Receive Timing ...................................................................................................... 84
33
10BASE-T Transmit Timing (Parallel Mode) ................................................................................. 85
34
10BASE-T Receive Timing (Parallel Mode) .................................................................................. 86
35
10BASE-T SQE (Heartbeat) Timing .............................................................................................. 87
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Figures
36
10BASE-T Jab and Unjab Timing.................................................................................................. 87
37
Fast Link Pulse Timing .................................................................................................................. 88
38
FLP Burst Timing........................................................................................................................... 88
39
MDIO Input Timing ........................................................................................................................ 89
40
MDIO Output Timing...................................................................................................................... 89
41
Power-Up Timing........................................................................................................................... 90
42
RESET Pulse Width and Recovery Timing ................................................................................... 90
43
Mechanical Specifications ............................................................................................................. 92
44
Example of Top Marking Information Labeled as Cortina Systems, Inc........................................ 93
45
Sample PQFP Package (marked as Intel*) – LXT973QC Transceiver ......................................... 93
46
Sample Pb-Free (RoHS-Compliant) PQFP Package (marked as Intel*) –
Intel* EGLX973QC Transceiver ............................................................................................... 94
47
Ordering Information – Sample ..................................................................................................... 96
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Tables
Tables
1
PQFP Pin List ................................................................................................................................ 15
2
Port 0 Signal Descriptions ............................................................................................................. 18
3
Port 1 Signal Descriptions ............................................................................................................. 19
4
Network Interface Signal Descriptions........................................................................................... 20
5
Global Control & Configuration Signal Descriptions ...................................................................... 21
6
Power Supply Signal Descriptions................................................................................................. 22
7
Per Port LED and Configuration Signal Descriptions .................................................................... 22
8
Carrier Sense, Loopback, and Collision Conditions ...................................................................... 28
9
Configuration Settings (Hardware Control Interface)..................................................................... 33
10
LED Configurations ....................................................................................................................... 41
11
Magnetics Requirements............................................................................................................... 45
12
Mode Control Settings ................................................................................................................... 52
13
Configuration Settings (Hardware Control Interface)..................................................................... 53
14
Common Register Set ................................................................................................................... 65
15
Register Bit Descriptions ............................................................................................................... 65
16
Control Register (Address 0) ......................................................................................................... 66
17
Status Register (Address 1) .......................................................................................................... 67
18
PHY Identification Register 1 (Address 2) ..................................................................................... 68
19
PHY Identification Register 2 (Address 3) ..................................................................................... 68
20
Auto-Negotiation Advertisement Register (Address 4).................................................................. 69
21
Auto-Negotiation Link Partner Base Page Ability Register (Address 5) ........................................ 70
22
Auto-Negotiation Expansion Register (Address 6) ........................................................................ 71
23
Auto-Negotiation Next Page Transmit Register (Address 7) ......................................................... 71
24
Auto-Negotiation Link Partner Next Page Ability Register (Address 8) ......................................... 72
25
Port Configuration Register (Address 16)...................................................................................... 72
26
Special Function Register (Address 27) ........................................................................................ 73
27
Magnetics Requirements............................................................................................................... 75
28
Absolute Maximum Ratings........................................................................................................... 76
29
Operating Conditions..................................................................................................................... 76
30
Digital Input/Output Characteristics2 ..............................................................................................................................77
31
Digital Input/Output Characteristics - SD Pins............................................................................... 77
32
Digital Input/Output Characteristics - MII Pins............................................................................... 78
33
REFCLK Characteristics................................................................................................................ 78
34
LED Pin Characteristics................................................................................................................. 78
35
100BASE-TX Transceiver Characteristics..................................................................................... 79
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Tables
36
10BASE-T Transceiver Characteristics ......................................................................................... 79
37
100BASE-FX Transceiver Characteristics..................................................................................... 79
38
10BASE-T Link Integrity Timing Characteristics............................................................................ 80
39
Twisted-Pair Pins........................................................................................................................... 80
40
MII - 100BASE-TX Transmit Timing Parameters - 4B Mode ......................................................... 81
41
MII - 100BASE-TX Receive Timing Parameters - 4B Mode .......................................................... 82
42
100BASE-FX Transmit Timing Parameters................................................................................... 83
43
100BASE-FX Receive Timing Parameters.................................................................................... 84
44
MII - 10BASE-T Transmit Timing Parameters (Parallel Mode)...................................................... 85
45
MII - 10BASE-T Receive Timing Parameters (Parallel Mode)....................................................... 86
46
10BASE-T SQE (Heartbeat) Timing Parameters .......................................................................... 87
47
10BASE-T Jab and Unjab Timing Parameters .............................................................................. 87
48
Fast Link Pulse Timing Parameters............................................................................................... 88
49
MDIO Timing Parameters.............................................................................................................. 89
50
Power-Up Timing Parameters ....................................................................................................... 90
51
RESET Pulse Width and Recovery Timing Parameters................................................................ 91
52
Product Ordering Information ........................................................................................................ 95
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Revision History
Revision History
Revision 7.0
Revision Date: 23 August 2011
• Changed the following signal names throughout the datasheet:
Changed From
Changed To
DPAP/N_0
DIFAP/N_0
DPBP/N_0
DIFBP/N_0
DPBP/N_1
DIFAP/N_1
DPAP/N_1
DIFBP/N_1
• The pair type on pins 67 and 68 were changed to “A” in Table 4.
• The pair type on pins 71 and 72 were changed to “B” in Table 4.
Revision 6.0
Revision Date: 13 July 2007
Updated the product top marking diagrams
Revision 5.0
Revision Date: 06 July 2007
First release of this document from Cortina Systems, Inc.
Revision#: 004
Revision Date: 29 November 2005
Modified Figure 2, Pin Assignments, on page 14.
Added Section 16.1, Top Label Marking, on page 92.
Modified Table 52, Product Ordering Information, on page 95.
Modified Figure 47, Ordering Information – Sample, on page 96.
Revision Number: 003
Revision Date: 20 January 2004
First paragraph:
Modified first sentence
Modified third sentence - Changed "pseudo-ECL" to "Low Voltage PECL
Removed bullet under Product Features: Integrated termination resistors.
Modified descriptions for pins 35, 36, 93, and 94 in Table 2 “LXT973 Port 0 Signal Descriptions”.
Changed the last word for SD0 and SD1 under Description from "Low" to “GND” in Table 4 “LXT973 Network Interface Signal
Descriptions”.
Modified descriptions for pins 7 and 8 in Table 7 “LXT973 Per Port LED and Configuration Signal Descriptions”.
Changed PECL to LVPECL in second to last sentence in the first paragraph under Section 3.1, “Introduction”.
Replaced text under Section 3.2.1.3, “Fiber Interface”.
Modified text in second paragraph under Section 3.5.3, “Power-Down Mode”.
Modified bullets under Section 3.5.3.1, “Hardware Power-Down”.
Changed Register 11 to Register bit 0.11 under Section 3.5.3.2, “Software Power-Down”.
Changed PECL to LVPECL in third paragraph, first sentence under Section 3.8.1, “100BASE-X Network Operations”.
Modified Figure 10 “Protocol Sublayers” (changed "PECL Interface" to "LVPECL Interface".
Replaced text under Section 3.8.5, “Fiber PMD Sublayer”.
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Revision History
Revision Number: 003
Revision Date: 20 January 2004
Modified first sentence under Section 4.1.4, “MII Terminations”.
Replaced text under Section 4.1.5, “The Fiber Interface”.
Modified text under Section 4.1.7, “Magnetics Information”.
Replaced Figure 14 “Recommended LXT973-to-3.3 VFiber Transceiver Interface Circuitry”.
Added Figure 15 “Recommended LXT973-to-5 VFiber Transceiver Interface Circuitry”.
Added Figure 16 “ON Semiconductor* Triple PECL-to-LVPECL Logic Translator”.
Changed PECL to LVPECL in first paragraph, second sentence under Section 9.0, “Fiber Interface”.
Modified table note 2 in Table 29 “Port Configuration Register (Address 16)” (changed ”hardware pins” to “FIBER_TPn”.
Modified table note 2 in Table 41 “Digital Input/Output Characteristics2” – (changed “applies to all pins except MII...” to “applies to
all pins except SD, MII...”.
Added Table 42 “Digital Input/Output Characteristics - SD Pins”.
In Table 46 “100BASE-TX Transceiver Characteristics”:
Changed "Peak differential output voltage (single ended)" to "Peak-to-peak differential output voltage".
Changed "VOP" to "Vdiffp-p", and removed footnote #2 (and all references).
Modified Table 63 “Product Ordering Information”.
Revision Number: 002
Revision Date: June 2002
Figure 1 “LXT973 Block Diagram”:
Added note to diagram.
Under Section 3.8.4, “PMA Sublayer”:
Removed Table 10: 4B/5B Coding.
Section 3.10.1, “Monitoring Auto-Negotiation”: Removed paragraphs 3 and 4, and Figure 11.
Under Section 8.1, “Displaying Symbol Errors”:
Removed Table 16: 4B/5B Coding.
Section 12.0, “Register Definitions”
Removed “multiple 11-bit registers, with” from first sentence.
Table 20 “PHY Identification Register 2 (Address 3)”:
Changed default for Register bits 3.9:4 from “001110” to “100001”.
Table 29 “Absolute Maximum Ratings” Modified Power Supply: added VCCA, VCC, VCCPECL, VCCIO information.
Added three table notes.
Table 31 “Digital Input/Output Characteristics2”Modified table note 2.
Table 32 “Digital Input/Output Characteristics - MII Pins”
Removed “Driver Output Impedance.”
Table 34 “LED Pin Characteristics”
Added MAX value to Output High Current.
Table 35 “100BASE-TX Transceiver Characteristics”
Added Typ values.
Table 36 “10BASE-T Transceiver Characteristics”
Added/replaced Typ values.
Removed “Receiver Input Impedance.”
Table 37 “100BASE-FX Transceiver Characteristics”
Added Typ values
Table 38 “10BASE-T Link Integrity Timing Characteristics”
Added Typ value for Link Pulse Width
Added Table 39 “Twisted-Pair Pins”.
Modified Table 40 on page 77 through Table 49 on page 85.
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Revision History
Revision Number: 002
Revision Date: June 2002
Added Figure 39 “Power-Up Timing” and Table 50 “Power-Up Timing Parameters”.
Added Figure 40 “RESET Pulse Width and Recovery Timing” and Table 51 “RESET Pulse Width and Recovery Timing
Parameters”
Section A, “Product Ordering Information”:
Added product ordering information table and diagram.
Revision Number: 001
Revision Date: May 2001
Initial Release (Preliminary datasheet)
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Figure 1
Note:
Block diagram
See Table 4, Network Interface Signal Descriptions, on page 20 and Table 5, Global Control & Configuration Signal
Descriptions, on page 21 for complete network interface signal configurations
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1.0 Pin Assignments and Signal
Descriptions
1.0
Pin Assignments and Signal Descriptions
Figure 2
Pin Assignments
Package Topside Markings
Marking
Definition
Part #
LXT973 Transceiver is the unique identifier for this product family.
Rev #
Identifies the particular silicon “stepping” (Refer to Specification Update for additional
stepping information.)
Lot #
Identifies the batch.
FPO #
Identifies the Finish Process Order.
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Table 1
1.0 Pin Assignments and Signal
Descriptions
PQFP Pin List (Sheet 1 of 3)
Pin
Signal Names
Type1
Reference for Full
Description
1
TXD1_2
I
Table 3 on page 19
2
TXD1_3
I
Table 3 on page 19
3
COL1
O, TS
Table 3 on page 19
4
CRS1
O, TS
Table 3 on page 19
5
AUTO_NEG1
I
Table 7 on page 22
6
AUTO_NEG0
I
Table 7 on page 22
7
SD_2P5V/SPEED1
I
Table 7 on page 22
8
SD_2P5V/SPEED0
I
Table 7 on page 22
9
DUPLEX1
I
Table 7 on page 22
10
DUPLEX0
I
Table 7 on page 22
11
LED_CGF0
I
Table 5 on page 21
12
LED_CGF1
I
Table 5 on page 21
13
RESET
I
Table 5 on page 21
14
SGND
–
Table 6 on page 22
15
REFCLK
I
Table 5 on page 21
16
GNDD
–
Table 6 on page 22
17
FIBER_TP1
I
Table 7 on page 22
18
FIBER_TP0
I
Table 7 on page 22
19
MDDIS1
I
Table 3 on page 19
20
MDDIS0
I
Table 2 on page 18
21
PWRDWN1
I
Table 7 on page 22
22
MDC1
I
Table 3 on page 19
23
MDIO1
I/O
Table 3 on page 19
24
PWRDWN0
I
Table 7 on page 22
25
MDIO0
I/O
Table 2 on page 18
26
MDC0
I
Table 2 on page 18
27
VCCIO
–
Table 6 on page 22
28
GNDIO
–
Table 6 on page 22
29
RXD0_3
O, TS
Table 2 on page 18
30
RXD0_2
O, TS
Table 2 on page 18
31
RXD0_1
O, TS
Table 2 on page 18
32
RXD0_0
O, TS
Table 2 on page 18
33
RXDV0
O, TS
Table 2 on page 18
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output,
OD = Open Drain output, ST = Schmitt Triggered input,
TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-down.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 15
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 1
1.0 Pin Assignments and Signal
Descriptions
PQFP Pin List (Sheet 2 of 3)
Pin
Signal Names
Type1
Reference for Full
Description
34
RXCLK0
O, TS
Table 2 on page 18
35
RXER0
O, TS
Table 2 on page 18
36
TXER0
I
Table 2 on page 18
37
TXCLK0
O, TS
Table 2 on page 18
38
TXEN0
I
Table 2 on page 18
39
TXD0_0
I
Table 2 on page 18
40
VCCD
–
Table 6 on page 22
41
GNDD
–
Table 6 on page 22
42
TXD0_1
I
Table 2 on page 18
43
TXD0_2
I
Table 2 on page 18
44
TXD0_3
I
Table 2 on page 18
45
COL0
O, TS
Table 2 on page 18
46
CRS0
O, TS
Table 2 on page 18
47
VCCIO
–
Table 6 on page 22
48
GNDIO
–
Table 6 on page 22
49
LED0_1
O, OD
Table 7 on page 22
50
LED0_2
O, OD
Table 7 on page 22
51
LED0_3
O, OD
Table 7 on page 22
52
ADDR4
I
Table 5 on page 21
53
ADDR3
I
Table 5 on page 21
54
ADDR2
I
Table 5 on page 21
55
ADDR1
I
Table 5 on page 21
56
TEST_0
I
Table 5 on page 21
57
TEST_1
I
Table 5 on page 21
58
VCCR
–
Table 6 on page 22
59
DIFAP_0
AI/AO, SL
Table 4 on page 20
60
DIFAN_0
AI/AO, SL
Table 4 on page 20
61
GNDT
–
Table 6 on page 22
62
GNDR
–
Table 6 on page 22
63
DIFBP_0
AI/AO, SL
Table 4 on page 20
64
DIFBN_0
AI/AO, SL
Table 4 on page 20
65
VCCT
–
Table 6 on page 22
66
VCCT
–
Table 6 on page 22
67
DIFAP_1
AI/AO, SL
Table 4 on page 20
68
DIFAN_1
AI/AO, SL
Table 4 on page 20
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output,
OD = Open Drain output, ST = Schmitt Triggered input,
TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-down.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 16
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 1
1.0 Pin Assignments and Signal
Descriptions
PQFP Pin List (Sheet 3 of 3)
Pin
Signal Names
Type1
Reference for Full
Description
69
GNDR
–
Table 6 on page 22
70
GNDT
–
Table 6 on page 22
71
DIFBP_1
AI/AO, SL
Table 4 on page 20
72
DIFBN_1
AI/AO, SL
Table 4 on page 20
73
VCCR
–
Table 6 on page 22
74
VCCPECL
–
Table 6 on page 22
75
SD1
I
Table 4 on page 20
76
SD0
I
Table 4 on page 20
77
GNDPECL
–
Table 6 on page 22
78
TxSLEW0
I
Table 5 on page 21
79
TxSLEW1
I
Table 5 on page 21
80
LED1_3
O. OD
Table 7 on page 22
81
LED1_2
O, OD
Table 7 on page 22
82
LED1_1
O, OD
Table 7 on page 22
83
GNDIO
–
Table 6 on page 22
84
VCCIO
–
Table 6 on page 22
85
RXD1_3
O, TS
Table 3 on page 19
86
RXD1_2
O, TS
Table 3 on page 19
87
RXD1_1
O, TS
Table 3 on page 19
88
RXD1_0
O, TS
Table 3 on page 19
89
RXDV1
O, TS
Table 3 on page 19
90
GNDD
–
Table 6 on page 22
91
VCCD
–
Table 3 on page 19
92
RXCLK1
O, TS
Table 3 on page 19
93
RXER1
O, TS
Table 3 on page 19
94
TXER1
I
Table 6 on page 22
95
GNDIO
–
Table 6 on page 22
96
VCCIO
–
Table 3 on page 19
97
TXCLK1
O, TS
Table 3 on page 19
98
TXEN1
I
Table 3 on page 19
99
TXD1_0
I
Table 3 on page 19
100
TXD1_1
I
Table 3 on page 19
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output,
OD = Open Drain output, ST = Schmitt Triggered input,
TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-down.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 17
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
2.0 Signal Descriptions
2.0
Signal Descriptions
Table 2
Port 0 Signal Descriptions (Sheet 1 of 2)
Pin #
Signal Names
Type1
Signal Description
I
Transmit Data. TXD0_n is a bundle of parallel data signals driven by
the MAC controller, which TXD0 transition synchronously with
respect to the TXCLK0. TXD0 is the least significant bit.
TXD0 are monitored in normal mode only.
44
TXD0_3
43
TXD0_2
42
TXD0_1
39
TXD0_0
38
TXEN0
I
Transmit Enable. The MAC asserts TXEN0 when it drives data on
TXD0n. This signal must be synchronized to TXCLK0.
36
TXER0
I
Transmit Error. TXER0 is a 100 Mbps only signal. The MAC asserts
this input when an error has occurred in the transmit data stream.
When operating at 100 Mbps, the LXT973 Transceiver responds by
sending "H symbols” on the line.
37
TXCLK0
O, TS
Transmit Clock. TXCLK0 is sourced by the LXT973 Transceiver in
both 10 Mbps and 100 Mbps modes.
2.5 MHz for 10 Mbps operation
25 MHz for 100 Mbps operation.
29
RXD0_3
30
RXD0_2
31
RXD0_1
O, TS
Receive Data.The LXT973 Transceiver drives received data on these
outputs, synchronous to RXCLK0.
32
RXD0_0
33
RXDV0
O, TS
Receive Data Valid. The LXT973 Transceiver asserts this signal
when it drives valid data on RXD0n. This output is synchronous to
RXCLK0.
35
RXER0
O, TS
Receive Error. The LXT973 Transceiver asserts this output when it
receives invalid symbols from the network. RXER0 is synchronous to
RXCLK0.
34
RXCLK0
O, TS
Receive Clock. RXCLK0 is sourced by the LXT973 Transceiver in
both 10 Mbps and 100 Mbps modes.
2.5 MHz for 10 Mbps operation
25 MHz for 100 Mbps operation.
45
COL0
O, TS
Collision Detected. The LXT973 Transceiver asserts this output
when a collision is detected. This output remains High for the duration
of the collision. COL0 is asynchronous and is inactive during
full-duplex operation.
46
CRS0
O, TS
Carrier Sense. During half-duplex operation, the LXT973 Transceiver
asserts this output when either the transmit or receive medium is
non-idle. During full-duplex operation, CRS0 is asserted only when
receive medium is non-idle.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-down.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 18
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 2
2.0 Signal Descriptions
Port 0 Signal Descriptions (Sheet 2 of 2)
Pin #
Signal Names
Type1
Signal Description
Management Disable. When MDDIS0 is tied High, the MDIO port is
completely disabled and the Hardware Control Interface pins set their
respective bits at power-up and reset.
20
MDDIS0
I
26
MDC0
I
25
MDIO0
I/O
When MDDIS0 is pulled Low at power-up or reset via the internal
pull-down resistor or by tying it to ground, the Hardware Control
Interface Pins control only the initial or “default” values of their
respective register bits. After the power-up/reset cycle is complete, bit
control reverts to the MDIO serial channel.
Management Data Clock. Clock for MDIO0 serial channel. Maximum
frequency is 20 MHz.
Management Data Input/Output. Bi-directional serial data channel
for PHY/STA communication.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-down.
Table 3
Port 1 Signal Descriptions (Sheet 1 of 2)
Pin #
Signal Names
Type1
Signal Description
I
Transmit Data. TXD1_n is a bundle of parallel data signals driven by
the MAC controller. TXD1 transition synchronously with respect
to the TXCLK1. TXD1 is the least significant bit. In normal mode,
only TXD1 are monitored.
2
TXD1_3
1
TXD1_2
100
TXD1_1
99
TXD1_0
98
TXEN1
I
Transmit Enable. The MAC asserts TXEN1 when it drives data on
TXD0n. This signal must be synchronized to TXCLK1.
94
TXER1
I
Transmit Error. (TXER1 is a 100 Mbps only signal.) The MAC asserts
this input when an error has occurred in the transmit data stream.
When operating at 100 Mbps, the LXT973 Transceiver responds by
sending "H Symbols" on the line.
97
TXCLK1
O, TS
Transmit Clock. TXCLK1 is sourced by the LXT973 Transceiver in
both 10 Mbps and 100 Mbps modes.
2.5 MHz for 10 Mbps operation
25 MHz for 100 Mbps operation.
85
RXD1_3
86
RXD1_2
87
RXD1_1
O, TS
Receive Data.The LXT973 Transceiver drives received data on these
outputs, synchronous to RXCLK1.
88
RXD1_0
89
RXDV1
O, TS
Receive Data Valid. The LXT973 Transceiver asserts this signal
when it drives valid data on RXD0n. This output is synchronous to
RXCLK1.
93
RXER1
O, TS
Receive Error. The LXT973 Transceiver asserts this output when it
receives invalid symbols from the network. RXER1 is synchronous to
RXCLK1.
92
RXCLK1
O, TS
Receive Clock. RXCLK1 is sourced by the LXT973 Transceiver in
both 10 Mbps and 100 Mbps modes.
2.5 MHz for 10 Mbps operation
25 MHz for 100 Mbps operation.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 19
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 3
2.0 Signal Descriptions
Port 1 Signal Descriptions (Sheet 2 of 2)
Signal Names
Type1
Signal Description
3
COL1
O, TS
Collision Detected. The LXT973 Transceiver asserts this output
when a collision is detected. This output remains High for the duration
of the collision. COL is asynchronous and is inactive during full-duplex
operation.
4
CRS1
O, TS
Carrier Sense. During half-duplex operation, the LXT973 Transceiver
asserts this output when either the transmit or receive medium is
non-idle. During full-duplex operation, CRS1 is asserted only when
receive medium is non-idle.
Pin #
Management Disable. When MDDIS is tied High, the MDIO port is
completely disabled and the Hardware Control Interface pins set their
respective bits at power-up and reset.
When MDDIS is pulled Low at power-up or reset via the internal
pull-down resistor or by tieing it to ground, the Hardware Control
Interface Pins control only the initial or “default” values of their
respective register bits. After the power-up/reset cycle is complete, bit
control reverts to the MDIO serial channel.
19
MDDIS1
I
22
MDC1
I
Management Data Clock. Clock for MDIO1 serial channel. Maximum
frequency is 20 MHz.
(Note: 20 MHz value to be verified prior to final production release of
product.)
23
MDIO1
I/O
Management Data Input/Output. Bidirectional serial data channel for
PHY/STA communication.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Table 4
Network Interface Signal Descriptions (Sheet 1 of 2)
Pin #
Signal
Names
TP
Op
Fiber
Op
Port
Pair
Type
59
DIFAP_0
TX+
RX+
0
A
60
DIFAN_0
TX-
RX-
0
A
Type1
AI/AO,
SL
Signal Description
Twisted-Pair/Fiber Pair A, Positive &
Negative - Port 0. Differential pair produces
or receives IEEE 802.3-compliant pulses for
either 100BASE-TX or 10BASE-T.
Also acts as receiver in Fiber mode.
63
DIFBP_0
RX+
TX+
0
B
64
DIFBN_0
RX-
TX-
0
B
AI/AO,
SL
Twisted-Pair/Fiber Pair B, Positive &
Negative - Port 0. Differential pair produces
or receives IEEE 802.3-compliant pulses for
either 100BASE-TX or 10BASE-T.
Also acts as transmitter in Fiber mode.
76
SD0
–
–
–
–
I
Signal Detect. This signal is used for signal
quality indication in Fiber mode. In twistedpair mode, this pin should be tied to GND.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 20
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 4
2.0 Signal Descriptions
Network Interface Signal Descriptions (Sheet 2 of 2)
Pin #
Signal
Names
TP
Op
Fiber
Op
67
DIFAP_1
TX+
68
DIFAN_1
TX-
TXTX+
Port
Pair
Type
Type1
1
A
1
A
AI/AO,
SL
Signal Description
Twisted-Pair/Fiber Pair B, Positive &
Negative - Port 1. Differential pair produces
or receives IEEE 802.3-compliant pulses for
either 100BASE-TX or 10BASE-T.
Also acts as transmitter in Fiber mode.
71
DIFBP_1
RX+
RX-
1
B
72
DIFBN_1
RX-
RX+
1
B
AI/AO,
SL
Twisted-Pair/Fiber Pair A, Positive &
Negative - Port 1. Differential pair produces
or receives IEEE 802.3-compliant pulses for
either 100BASE-TX or 10BASE-T.
Also acts as receiver in Fiber mode.
75
SD1
–
–
–
–
I
Signal Detect. This signal is used for signal
quality indication in Fiber mode. In
twisted-pair mode, this pin should be tied to
GND.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Table 5
Global Control & Configuration Signal Descriptions
Pin
#
Signal
Names
78
TxSLEW0
79
TxSLEW1
13
RESET
52
ADDR4
53
ADDR3
54
ADDR2
55
ADDR1
56
TEST_0
57
TEST_1
15
REFCLK
Type1
I
Signal Description
Tx Output Slew Controls 0 & 1. These pins select the TX output slew rate
(rise and fall time) for both cores in the LXT973 Transceiver.
The various options are defined in Register bits 27.11:10. The TxSLEW pins
set the power-on value of these register bits.
I
Reset. This active Low input is OR’d with Control Register bit 0.15.
I
Address . Sets device Port 0 PHY address. Note that ADDR0 is set
internally so that Port 1 is always “1” address higher than Port 0.
I
Test Pins. Tie Low for normal operation.
I
Master Clock Input. A 25 MHz, 50 ppm clock is input here to act as the master
clock. Full clock requirements are detailed in the Clock Requirements section
of the Functional Description. See Section 3.4.2, Clock Requirements, on
page 30.
LED Configuration 0 & 1. These pins are used to select one of four LED
modes. The decode or each mode is shown below:
11
LED_CFG0
12
LED_CFG1
I
LED_CFG0
LED_CFG1
LEDn_1
LEDn_2
0
0
Speed
Link
LEDn_3
Duplex
1
0
Speed
Link/Activity
Duplex/Collision
0
1
Link
Receive
Transmit
1
1
Speed
Link/MII Isolate
Duplex/Collision
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 21
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 6
2.0 Signal Descriptions
Power Supply Signal Descriptions
Pin #
40, 91
Signal Names
VCCD
Type1
Signal Description
–
Digital Power Supply - Core. +2.5 V supply for core digital circuits.
27, 47,
84, 96
VCCIO
–
Digital Power Supply - I/O Ring. +2.5/3.3 V supply for digital I/O
circuits. The digital input circuits running off this rail, having a
TTL-level threshold and over-voltage protection, may be interfaced
with 3.3/5.0V when the I/O supply is 3.3 V, and 2.5/3.3/5.0V when the
I/O supply is 2.5 V.
74
VCCPECL
–
Digital Power Supply - PECL Signal Detect Inputs. +2.5/3.3 V
supply for PECL Signal Detect input circuits. If Fiber Mode is not used,
tie these pins to GNDPECL to save power.
58, 73
VCCR
–
Analog Power Supply - Receive. +2.5 V supply for all analog
receive circuits.
65, 66
VCCT
–
Analog Power Supply - Transmit. +2.5 V supply for all analog
transmit circuits.
16, 41,
90,
GNDD
–
Digital Ground. Ground return for core digital supplies (VCCD). All
ground pins can be tied together using a single ground plane.
28, 48,
83, 95
GNDIO
–
Digital GND - I/O Ring. Ground return for digital I/O circuits
(VCCIO).
77
GNDPECL
–
Digital GND - PECL Signal Detect Inputs. Ground return for PECL
Signal Detect input circuits.
69, 62
GNDR
–
Analog Ground - Receive. Ground return for receive analog supply.
All ground pins can be tied together using a single ground plane.
61, 70
GNDT
–
Analog Ground - Transmit. Ground return for transmit analog supply.
All ground pins can be tied together using a single ground plane.
14
SGND
–
Substrate Ground. Ground for chip substrate. All ground pins can be
tied together using a single ground plane.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Table 7
Per Port LED and Configuration Signal Descriptions (Sheet 1 of 2)
Pin #
Signal Names
Type1
49
LED0_1
50
LED0_2
51
LED0_3
82
LED1_1
81
LED1_2
80
LED1_3
6
AUTO_NEG0
I
5
AUTO_NEG1
I
Signal Description
OD, TS,
SL, IP
Port 0 LED Drivers 1-3. These pins drive LED indicators for Port 0.
Each LED can display one of several available status conditions as
selected by the LED Configuration Register.
OD, TS,
SL, IP
Port 1 LED Drivers 1-3. These pins drive LED indicators for Port 1.
Each LED can display one of several available status conditions as
selected by the LED Configuration Register.
Auto Negotiation Enable. When this pin is High, auto-negotiation is
enabled on the relevant port.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 22
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 7
2.0 Signal Descriptions
Per Port LED and Configuration Signal Descriptions (Sheet 2 of 2)
Pin #
8
Signal Names
SD_2P5V/SPE
ED0
Type1
I
Signal Description
SD_2P5V. In fiber mode, this pin selects between 2.5 V or 3.3 V fiber
transceiver thresholds for both ports.
High = 2.5 V
Low = 3.3 V
Speed. In copper mode, this pin sets the default speed of Port 0 in
Hardware mode.
High = 100 Mbps
Low = 10 Mbps
SD_2P5V. In fiber mode, the speed of both ports defaults to
100BASE-FX. Pin 7 should be tied to ground.
7
SD_2P5V/SPE
ED1
I
Speed. In copper mode, this pin sets the default speed of Port 1 in
Hardware mode.
High = 100 Mbps
Low = 10 Mbps
10
DUPLEX0
I
9
DUPLEX1
I
Duplex. Sets the duplex setting of the port in Hardware mode. High is
full-duplex and Low is half-duplex.
18
FIBER_TP0
I
17
FIBER_TP1
I
24
PWRDWN0
21
PWRDWN1
I
Fiber/Twisted-Pair. Sets the operating state of the port in Hardware
mode. High is twisted-pair and Low is fiber.
Power-Down. When set High, this pin puts the relevant PHY into
power-down mode.
1. AI = Analog Input, AO = Analog Output, I = Input, O = Output, OD = Open Drain output,
ST = Schmitt Triggered input, TS = Three-State-able output, SL = Slew-rate Limited output,
IP = Weak Internal Pull-up, ID = Weak Internal Pull-Down
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 23
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
3.0
Functional Description
3.1
Introduction
3.0 Functional Description
The Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
(LXT973 Transceiver) is an IEEE-compliant, dual-port, Fast Ethernet PHY transceiver that
directly supports both 100BASE-TX and 10BASE-T applications. The device incorporates
full Media Independent Interface (MII), enabling each individual network port to connect with
10/100 Mbps MACs. Each port directly drives either a 100BASE-TX line or a 10BASE-T line
(up to 160 meters). The LXT973 Transceiver also supports 100BASE-FX operation via an
LVPECL interface. The device uses a 100-pin QFP package.
3.1.1
Comprehensive Functionality
The LXT973 Transceiver performs all functions of the Physical Coding Sublayer (PCS) and
Physical Media Attachment (PMA) sublayer as defined in the IEEE 802.3 100BASE-X
specification. This device also performs all functions of the Physical Media Dependent
(PMD) sublayer for 100BASE-TX connections.
On power-up, the LXT973 Transceiver reads its configuration inputs to check for forced
operation settings. If not configured for forced operation, each port uses
auto-negotiation/parallel detection to automatically determine line operating conditions. If
the link partner supports auto-negotiation, the LXT973 Transceiver auto-negotiates with it
using Fast Link Pulse (FLP) Bursts. If the PHY partner does not support auto-negotiation,
the LXT973 Transceiver automatically detects (parallel detection) the presence of either link
pulses (10 Mbps PHY) or IDLE symbols (100 Mbps PHY) and sets its operating conditions
accordingly. When parallel detection is used to establish link, the resulting link is at
half-duplex. The LXT973 Transceiver provides half-duplex and full-duplex operation at
100 Mbps and 10 Mbps.
3.2
Interface Descriptions
3.2.1
10/100 Mbps Network Interface
The LXT973 Transceiver supports both 10BASE-T and 100BASE-TX Ethernet over
twisted-pair, or 100 Mbps Ethernet over fiber media (100BASE-FX). Each network interface
port consists of four external pins (two differential signal pairs). The pins are shared
between twisted-pair and fiber.
The LXT973 Transceiver output drivers generate either 100BASE-TX, 10BASE-T, or
100BASE-FX output. When not transmitting data, the device generates IEEE
802.3-compliant link pulses or IDLE code. Input signals are decoded either as a
100BASE-TX, 100BASE-FX, or 10BASE-T input, depending on the mode selected.
Auto-negotiation/parallel detection or manual control is used to determine the speed of this
interface. Polarity is determined by the MDI crossover function.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 24
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 3
Interfaces
3.2.1.1
Twisted-Pair Interface
3.2 Interface Descriptions
The LXT973 Transceiver supports either 100BASE-TX or 10BASE-T connections over
100CategoryUnshielded Twisted-Pair (UTP). Only a transformer, RJ-45, and bypass
capacitors are required to complete this interface. The transmitter shapes the outgoing
signal to help reduce the need for external EMI filters. Four slew rate settings allow the
designer to match the output waveform to the magnetic characteristics. Both transmit and
receive terminations are built into the LXT973 Transceiver. Therefore, no external
components are required between the LXT973 Transceiver and the external transformer.
The transmitter uses a transformer with a center tap to help reduce power consumption.
When operating at 100 Mbps, MLT3 symbols are continuously transmitted and received.
When not transmitting data, the LXT973 Transceiver generates “IDLE” symbols.
During 10 Mbps operation, LXT973 Transceiver encoded data is exchanged. When no data
is exchanged, the line transmits normal link pulses to maintain link.
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3.2.1.2
3.3 MII Operation
MDI Crossover (MDIX)
The LXT973 Transceiver crossover function, which is compliant to the IEEE 802.3, clause
23 standard, connects the transmit output of the device to the far-end receiver in a link
segment. This function can be configured via Register bits 27.9:8. Please refer to
Section 7.0, Auto-MDI/MDIX, on page 56. Default mode is auto-MDIX enabled.
3.2.1.3
Fiber Interface
The LXT973 Transceiver fiber ports are designed to interface with common
industry-standard 3.3 V and 5 V fiber-optic transceivers. Each port incorporates a Low
Voltage PECL interface that complies with the ANSI X3.166 standard for seamless
integration.
Fiber mode is selected through Register bit 16.0 by the following two methods:
1. Configure Register bit 16.0 = 1 on a per-port basis by driving the Hardware Control pin
FIBER_TPn (on the respective port) to a logic Low value on power-up and/or reset.
2. Configure Register bit 16.0 = 1 on a per-port basis through the MDIO interface.
3.3
MII Operation
The LXT973 Transceiver implements the Media Independent Interface (MII) as defined in
the IEEE 802.3 standard. Separate channels are provided for transmitting data from the
MAC to the LXT973 Transceiver (TXD), and for passing data received from the line (RXD)
to the MAC. Each channel has its own clock, data bus, and control signals. Nine signals are
used to pass received data to the MAC: RXD, RXCLK, RXDV, RXER, COL and CRS.
Seven signals are used to transmit data from the MAC: TXD, TXCLK, TXEN, and
TXER.
The LXT973 Transceiver supplies both clock signals as well as separate outputs for carrier
sense and collision. Data transmission across the MII is normally implemented in 4-bit-wide
nibbles.
3.3.1
MII Clocks
The LXT973 Transceiver is the master clock source for data transmission and supplies both
MII clocks (RXCLK and TXCLK). It automatically sets the clock speeds to match link
conditions. When the link is operating at 100 Mbps, the clocks are set to 25 MHz. When the
link is operating at 10 Mbps, the clocks are set to 2.5 MHz. The transmit data and control
signals must always be synchronized to TXCLK by the MAC. The LXT973 Transceiver
samples these signals on the rising edge of TXCLK.
3.3.2
Transmit Enable
The MAC must assert TXEN at the same time as the first nibble of preamble, and de-assert
TXEN after the last bit of the packet.
3.3.3
Receive Data Valid
The LXT973 Transceiver asserts RXDV when it receives a valid packet. Timing changes
depend on line operating speed:
• For 100BASE-TX links, RXDV is asserted from the first nibble of preamble to the last
nibble of the data packet.
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3.3 MII Operation
• For 10BASE-T links, the entire preamble is truncated. RXDV is asserted with the first
nibble of the Start-of-Frame Delimiter (SFD) “5D” and remains asserted until the end of
the packet.
3.3.4
Carrier Sense
Carrier Sense (CRS) is an asynchronous output. CRS is generated when a packet is
received from the line regardless of duplex mode, and for a transmission to the line in
half-duplex mode. Table 8 on page 28 summarizes the conditions for assertion of carrier
sense, collision, and data loopback signals. Carrier sense is not generated when a packet is
transmitted in full-duplex mode.
For 100BASE-TX and 100BASE-FX links, a Start-of-Stream Delimiter (SSD) or /J/K/ symbol
pair causes assertion of carrier sense (CRS). An End-of-Stream Delimiter (ESD), or /T/R/
symbol pair causes de-assertion of CRS. The PMA layer also de-asserts CRS if IDLE
symbols are received without /T/R/. In this event, the RXER bit in the RX Status Frame is
asserted for one clock cycle when CRS is de-asserted.
For 10BASE-T links, CRS assertion is based on receipt of a valid preamble, and
de-assertion is based on receipt of an End-of-Frame (EOF) marker.
3.3.5
Error Signals
When the LXT973 Transceiver is in 100 Mbps mode and receives an invalid symbol from
the network, it asserts RXER and drives “1110” on the RXD pins.
When the MAC asserts TXER, the LXT973 Transceiver drives “H” symbols out on the
DIFAP/N_0 or DIFBP/N_1 pins.
3.3.6
Collision
The LXT973 Transceiver asserts its collision signal, asynchronously to any clock, when the
line state is half-duplex and the transmitter and receiver are active at the same time.
Table 8 on page 28 summarizes the conditions for assertion of carrier sense, collision, and
data loopback signals.
3.3.7
Loopback
The LXT973 Transceiver provides two loopback functions, operational and test (see
Table 8 on page 28). Loopback paths are shown in Figure 4 on page 28.
3.3.7.1
Operational Loopback
Operational loopback is provided for 10 Mbps half-duplex links when Register bit 16.8 = 0.
Data transmitted by the MAC (TXD) is looped back on the receive side of the MII (RXD).
Operational loopback is not provided for 100 Mbps links, full-duplex links, or when Register
bit 16.8 = 1.
3.3.7.2
Test Loopback
A test loopback function is provided for diagnostic testing of the LXT973 Transceiver.
During test loopback, twisted-pair and fiber interfaces are disabled. Data transmitted by the
MAC is internally looped back by the LXT973 Transceiver and returned to the MAC (see
Figure 4).
Test loopback is available for both 100BASE-TX and 10BASE-T operation and is enabled
by setting the following register bits:
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3.3 MII Operation
• Register bit 0.14 = 1 (loopback mode)
• Register bit 0.8 = 1 (full-duplex)
• Register bit 0.12 = 0 (disable auto-negotiation).
Figure 4
Loopback Paths
LXT973
FX
Driver
MII
10T
Loopback
Digital
Block
100X
Loopback
Analog
Block
TX
Driver
Table 8
Carrier Sense, Loopback, and Collision Conditions
Speed
100 Mbps
10 Mbps
Duplex Condition
Carrier Sense
Test
Loopback1
Operational
Loopback
Collision
Full-Duplex
Receive Only
Yes
No
None
Full-Duplex
Receive Only
No
No
None
Half-Duplex
Transmit or
Receive
No
No
Transmit and
Receive
Full-Duplex
Receive Only
Yes
No
None
Full-Duplex
Receive Only
No
No
None
Half-Duplex,
Register bit 16.8 = 0
Transmit or
Receive
Yes
Yes
Transmit and
Receive
Half-Duplex,
Register bit 16.8 = 1
Transmit or
Receive
No
No
Transmit and
Receive
1. Test loopback is enabled when Register bit 0.14 = 1, Register bit 0.8 = 1, and Register bit 0.12 = 0.
3.3.8
Configuration Management Interface
The LXT973 Transceiver provides an MDIO Management Interface and a Hardware Control
Interface for device configuration and management.
3.3.8.1
MII Management Interface
The LXT973 Transceiver supports the IEEE 802.3 MII Management Interface also known
as the Management Data Input/Output (MDIO) Interface. This interface allows upper-layer
devices to monitor and control the state of the LXT973 Transceiver. The MDIO interface
consists of a physical connection, a specific protocol which runs across the connection, and
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3.3 MII Operation
an internal set of addressable registers. The physical interface consists of a data line
(MDIO) and clock line (MDC), and a control line (MDDIS). The maximum speed of MDC is
20 MHz.
Operation of this interface is controlled by the MDDISn input pin. When MDDISn is High, the
MDIO is completely disabled. When MDDISn is Low, read and write are enabled. The timing
for the MDIO Interface is shown in Table 49 on page 89. See Figure 5 for read operations,
and Figure 6 for write operations. The protocol allows one controller to communicate with
multiple
LXT973 Transceiver devices. Each LXT973 Transceiver port is assigned an address
between 0 and 31, as described in Table 5 on page 21 (ADDR).
The LXT973 Transceiver supports the core 16-bit MDIO registers. Registers 0-10 and 15
are required and their functions are specified by the IEEE 802.3 specification. Additional
registers are included for expanded functionality. Specific bits in the registers are
referenced using an “X.Y” notation, where X is the register number (0-31) and Y is the bit
number (0-15)
Figure 5
Management Interface Read Frame Structure
MDC
MDIO
(Read)
High Z
32 "1"s
0
1
Preamble
1
ST
A4
0
Op Code
A3
A0
PHY Address
R4
R3
R0
Register Address
Z
D15 D15
D14 D14D1 D1 D0
0
Turn
Around
Data
Write
Figure 6
Idle
Read
Management Interface Write Frame Structure
MDC
MDIO
(Write)
32 "1"s
Idle
Preamble
0
1
ST
0
1
Op Code
A4
A3
A0
R4
R3
Register Address
PHY Address
R0
0
1
Turn
Around
D15
D14
D1
Data
D0
Idle
Write
3.3.8.2
MII Addressing
The MDIO management protocol allows one controller to communicate with multiple
LXT973 Transceiver chips. Pins ADDR_ determine the base address. Each port adds
its port number to the base address to obtain its port address as shown in Figure 7 on
page 30.
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Figure 7
3.4 Operating Requirements
Port Address Scheme
BASE ADDR
Example ADDR = 0001
Port 0 = 2
Port 1 = 3
LXT973
3.3.8.3
Port 0
PHY ADDR (BASE+0)
ex. 2
Port 1
PHY ADDR (BASE+1)
ex. 3
Hardware Control Interface
The LXT973 Transceiver provides a Hardware Control Interface for applications where the
MDIO is not desired. Refer to Figure 18, Initialization Sequence, on page 51 for additional
details.
3.4
Operating Requirements
3.4.1
Power Requirements
The LXT973 Transceiver requires five power supply inputs: VCCD, VCCR, VCCT,
VCCPECL, and VCCIO. The digital and analog circuits require 2.5 V supplies (VCCD,
VCCR, and VCCT). These inputs may be supplied from a single source although
decoupling is required to each respective ground. The fiber VCCPECL supply can be
connected to either 2.5 V or 3.3 V.
A separate power supply may be used for MII and MDIO (VCCIO) interfaces. The power
supply may be either +2.5 V or +3.3 V. VCCIO should be supplied from the same power
source used to supply the controller on the other side of the interface. As a matter of good
practice, these supplies should be as clean as possible.
3.4.2
Clock Requirements
3.4.2.1
Reference Clock / External Oscillator
The LXT973 Transceiver requires a constant enabled reference clock (REFCLK). REFCLK
frequency must be 25 MHz. Considering overall system performance first, the clock is best
derived by providing a crystal-based oscillator. PLL-based oscillators with known stability
may also be used. In general, an oscillator-based clock source is recommended over a
derived clock due to frequency stability and overall signal integrity. Regardless of clock
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3.5 Initialization
source, careful consideration should be given to physical placement, board layout, and
signal routing of the source to maintain the highest possible level of signal integrity. Refer to
Table 33 on page 78 for clock timing requirements.
3.4.2.2
MDIO Clock
The MII management channel (MDIO) also requires an external clock. The managed data
clock (MDC) speed is a maximum of 20 MHz. Refer to Table 49 on page 89 for details.
3.5
Initialization
When the LXT973 Transceiver is first powered on, reset, or encounters a link failure state, it
checks the MDIO register configuration bits to determine the line speed and operating
conditions to use for the network link. The configuration bits may be set by the Hardware
Control or MDIO interface as shown in Table 9 on page 33.
3.5.1
MDIO Control Mode
In the MDIO Control mode, the LXT973 Transceiver reads the Hardware Control Interface
pins to set the initial (default) values of the MDIO registers. Once the initial values are set,
bit control reverts to the MDIO interface.
3.5.2
Hardware Control Mode
In the Hardware Control Mode, the LXT973 Transceiver disables direct write operations to
the MDIO registers via the MDIO Interface. On power-up or hardware reset the LXT973
Transceiver reads the Hardware Control Interface pins and sets the MDIO registers
accordingly.
The following modes are available using either Hardware Control or MDIO Control:
• Forced network link to 100BASE-FX (Fiber)
• Forced network link operation to:
100BASE-TX, full-duplex
100BASE-TX, half-duplex
10BASE-T, full-duplex
10BASE-T, half-duplex
• Allow auto-negotiation/parallel-detection
When the network link is forced to a specific configuration, the LXT973 Transceiver
immediately begins operating the network interface as commanded. When auto-negotiation
is enabled, the LXT973 Transceiver begins the auto-negotiation/parallel-detection
operation.
3.5.3
Power-Down Mode
The LXT973 Transceiver incorporates numerous features to maintain the lowest power
possible. The device can be put into a low-power state via Register 0 as well as a near-zero
power state with the power-down pins. When in power-down mode, the device is not
capable of receiving or transmitting packets.
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3.5 Initialization
The lowest power operation is achieved using the global power-down pins. These active
High pins power down every circuit in the device, including the clocks. All registers are
unaltered and maintained. When the power-down pins are released, the registers are
reloaded with the value of the last hardware reset.
Individual ports (software power-down) can be powered down using Control Register bit
0.11. This bit powers down a significant portion of the port, but clocks to the register section
remain active. This allows the management interface to remain active during register
power-down. The power-down bit is active High.
3.5.3.1
Hardware Power-Down
The hardware power-down per port mode is controlled by the PWRDWN 0/1 pins. When
PWRDWN 0/1 is High, the following conditions are true:
• LXT973 Transceiver ports and the clock are shut down.
• Outputs are three-stated.
• The MDIO registers are not accessible.
• Configuration pins are not read upon release of the PWRDWN 0/1 pins, and registers
are reloaded with the value of the last hardware reset.
3.5.3.2
Software Power-Down
Software port power-down control is provided by Register bit 0.11 in the respective port
Control Registers (refer to Table 16 on page 66). During individual port power-down, the
following conditions are true:
• The individual port is shut down.
• The MDIO registers remain accessible.
• The register remains unchanged.
3.5.4
Reset
The LXT973 Transceiver provides both hardware and software resets. Configuration control
of auto-negotiation, speed, and duplex mode selection is handled differently for each.
During a hardware reset, settings for Register bits 0.13, 0.12, and 0.8 are read in from the
pins (refer to Table 9 on page 33 for pin settings and Table 16 on page 66 for register bit
definitions).
During a software reset (Register bit 0.15 = 1), the bit settings are not re-read from the pins,
and revert back to the values that were read in during the last hardware reset. Any changes
to pin values from the last hardware reset are not detected during a software reset. Also,
during a software reset (Register bit 0.15 = 1), the registers are available for reading. The
reset bit is polled to see when the part has completed reset (Register bit 0.15 = 0).
During a hardware reset, register information is unavailable for 1 ms after de-assertion of
the reset. All the MII interface pins are disabled during a hardware reset and released to the
bus on de-assertion of reset.
3.5.5
Hardware Configuration Settings
The LXT973 Transceiver provides a hardware option to set the initial device configuration.
The hardware option uses four per-port configuration pins that provide control (see Table 9
on page 33).
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Table 9
3.6 Link Establishment
Configuration Settings (Hardware Control Interface)
FIBER/TP
x
AUTO-NEGx
SPEEDx
DUPLEXx
Low
-
-
Low
100BASE-FX is enabled in half-duplex mode.
Auto-negotiation is disabled.
Low
-
-
High
100BASE-FX is enabled in full-duplex mode.
Auto-negotiation is disabled.
High
High
High
High
AUTO_NEG is enabled. All capabilities are
advertised.
Register bits 4.8:5 are set to 1.
High
High
High
Low
High
High
Low
High
Mode
AUTO_NEG is enabled. Only 100 Mbps
capabilities are advertised.
Register bits 4.8:7 are set to 1. Register bits 4.6:5
are cleared to 0.
AUTO_NEG is enabled. Only 10 Mbps capability is
advertised.
Register bits 4.8:7 are cleared to 0. Register bits
4.6:5 are set to 1.
AUTO_NEG is enabled. Only half -duplex
capability is advertised.
High
High
Low
Low
High
Low
High
High
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 100 Mbps full-duplex operation.
High
Low
High
Low
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 100 Mbps half-duplex operation.
High
Low
Low
High
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 10 Mbps full-duplex operation.
High
Low
Low
Low
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 10 Mbps half-duplex operation.
Register bits 4.7 and 4.5 are set to 1. Register bits
4.8 and 4.6 are cleared to 0.
1. These pins also set the default values for Registers 0 and 4 accordingly.
3.6
Link Establishment
3.6.1
Auto-Negotiation
The LXT973 Transceiver attempts to auto-negotiate with its link partner by sending Fast
Link Pulse (FLP) bursts. Each burst consists of 33 pulse positions spaced 62.5 s apart.
Odd link pulses (clock pulses) are always present. Even link pulses (data pulses) may also
be present or absent to indicate a “1” or a “0”. Each FLP burst exchanges 16 bits of data,
referred to as a “page.” All devices that support auto-negotiation must implement the “Base
Page”, defined by IEEE 802.3 (Registers 4 and 5). The LXT973 Transceiver also supports
the optional “Next Page” function (Registers 7 and 8).
3.6.1.1
Base Page Exchange
By exchanging Base Pages, the LXT973 Transceiver and its link partner communicate their
capabilities to each other. Both sides must receive at least three identical base pages for
negotiation to proceed. Each side finds their highest common capabilities, exchange more
pages, and agree on the operating state of the line.
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3.6.1.2
3.6 Link Establishment
Next Page Exchange
Additional information, exceeding that required by Base Page exchange, can also be sent
via “Next Pages.” The LXT973 Transceiver fully supports the IEEE 802.3 method of
negotiation via Next Page exchange. The Next Page exchange uses Register 7 to send
information and Register 8 to receive information, and occurs only if both ends of the link
advertise their ability to exchange Next Pages. The LXT973 Transceiver is configured to
make Next Page exchange easier for software. When a Base Page or Next Page is
received, the Page Received Register bit 6.1 remains set until read. When Register bit 6.2
(Next Page Able) is received, it stays set until read. This bit should be cleared whenever a
new negotiation occurs. This prevents the user from reading an old value in Register 6 and
assuming there is valid information in Registers 5 and 8. Additionally, Register 6 contains a
new bit (Register bit 6.5) that indicates when the current Received Page is the Base Page.
This information is useful for recognizing when next pages must be re-sent due to the start
of a new negotiation process. Register bit 16.1 and the Page Received bit (Register bit 6.1)
are also cleared upon reading Register 6.
3.6.1.3
Controlling Auto-Negotiation
When auto-negotiation is controlled by software, the following steps are recommended:
3. After power-up, power-down, or reset, the power-down recovery time (max = 300 s)
must be exhausted before proceeding.
4. Set the auto-negotiation advertisement register bits.
5. Enable auto-negotiation (set MDIO Register bit 0.12 = 1).
3.6.1.4
Link Criteria
In 100 Mbps mode, link is established when the scrambler becomes locked and remains
locked for approximately 50 ms. Link remains up unless the de-scrambler receives less than
12 consecutive IDLE symbols in any 2 ms period. This provides a very robust operation,
filtering out any small noise hits that may disrupt the link.
In 10 Mbps mode, link is established based on the link state machine found in the IEEE
802.3, Clause 14.X specification. Receiving 100 Mbps idle patterns does not bring up a
10 Mbps link.
3.6.1.5
Parallel Detection
In parallel with auto-negotiation, the LXT973 Transceiver also monitors for 10 Mbps Normal
Link Pulses (NLP) or 100 Mbps IDLE symbols. If either is detected, the device automatically
reverts to the corresponding operating mode. Parallel detection allows the LXT973
Transceiver to communicate with devices that do not support auto-negotiation. The
established link is always set at half-duplex.
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Figure 8
3.7 Network Media/Protocol
Support
Auto-Negotiation Operation
Power-Up, Reset,
Link Failure
Start
Disable
Auto-Negotiation
Enable
0.12 = 1 Auto-Negotiation/Parallel Detection
0.12 = 0
Go To Forced
Settings
Check Value
0.12
Attempt AutoNegotiation
Done
3.7
YES
Listen for 100TX
Idle Symbols
Link Set?
Listen for 10T
Link Pulses
NO
Network Media/Protocol Support
The LXT973 Transceiver supports both 10BASE-T and 100BASE-TX Ethernet over
twisted-pair, or 100 Mbps Ethernet over fiber media (100BASE-FX).
3.7.1
10/100 Mbps Network Interface
The network interface port consists of five external pins (two differential signal pairs and a
signal detect pin). The differential signal pins are shared between twisted-pair and fiber.
Refer to Figure 3 on page 25 for specific pin assignments.
The LXT973 Transceiver output drivers generate either 100BASE-TX, 10BASE-T, or
100BASE-FX output. When not transmitting data, the LXT973 Transceiver generates IEEE
802.3-compliant link pulses or an IDLE code. Input signals are decoded either as a
100BASE-TX, 100BASE-FX, or 10BASE-T input, depending on the mode selected.
Auto-negotiation/parallel detection or manual control is used to determine the speed of this
interface.
3.7.2
Twisted-Pair Interface
When operating at 100 Mbps, the LXT973 Transceiver continuously transmits and receives
MLT3 symbols. When not transmitting data, the LXT973 Transceiver generates IDLE
symbols.
During 10 Mbps operation, Manchester-encoded data is exchanged. When no data is being
exchanged, the line is left in an idle state. Link pulses are transmitted periodically to keep
the link up.
The LXT973 Transceiver supports either 100BASE-TX or 10BASE-T connections over
100CategoryUnshielded Twisted-Pair (UTP) cable. Only a transformer, RJ-45
connector, and bypass capacitors are required to complete this interface. On the transmit
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3.7 Network Media/Protocol
Support
side, the waveshaping technology shapes the outgoing signal to help reduce the need for
external EMI filters. Four slew rate settings (refer to Table 5 on page 21) allow the designer
to match the output waveform to the magnetic characteristics.
3.7.3
Fiber Interface
The LXT973 Transceiver fiber port is designed to interface with common industry-standard
fiber modules. It incorporates a PECL interface that complies with the ANSI X3.166
standard for seamless integration.
Fiber mode is selected by putting a low level on the Fiber_TPn pin. This is only sensed
upon completion of reset.
3.7.4
Fault Detection and Reporting
The LXT973 Transceiver supports two fault detection and reporting mechanisms. “Remote
Fault” refers to a MAC-to-MAC communication function that is essentially transparent to
PHY layer devices, and is used only during auto-negotiation. Therefore, Remote Fault is
applicable only to twisted-pair links. "Far End Fault" is an optional PMA-layer function that
may be embedded within PHY devices. The LXT973 Transceiver supports both functions,
which are explained in more detail in sections that follow.
3.7.5
Remote Fault
Register bit 4.13 in the Auto-Negotiation Advertisement Register is reserved for Remote
Fault indications. This bit is typically used when restarting the auto-negotiation sequence,
indicating to the link partner that link is down because the advertising device detected a
fault.
When the LXT973 Transceiver receives a Remote Fault indication from its partner during
auto-negotiation it:
• Sets Register bit 5.13 in the Link Partner Base Page Ability Register, and
• Sets the Remote Fault Register bit 1.4 in the MII Status Register to pass this
information to the local controller.
3.7.6
Far End Fault
In fiber mode, the SDn pin monitors signal quality. If signal quality degrades beyond the fault
threshold, the fiber transceiver reports a signal quality fault condition via the SDn pin. Loss
of signal quality blocks any fiber data from being received and causes a loss of link.
If the LXT973 Transceiver detects a signal fault condition, it transmits the Far End Fault
Indication (FEFI) over the fiber link. The FEFI consists of 84 consecutive “1s” followed by a
single “0.” This pattern must be repeated at least three times. The LXT973 Transceiver
transmits the Far-End Fault code a minimum of three times if all the following conditions are
true:
• Fiber mode is selected.
• Far End Fault Code transmission is enabled (Register bit 16.2 = 1).
• Signal Detect indicates either no signal or the receive PLL cannot lock.
• Loopback is not enabled.
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3.8 100 Mbps Operation
3.8
100 Mbps Operation
3.8.1
100BASE-X Network Operations
During 100BASE-X operation, the LXT973 Transceiver transmits and receives 5-bit
symbols across the network link. Figure 9 shows the structure of a standard frame packet.
When the MAC is not actively transmitting data, the LXT973 Transceiver sends out IDLE
symbols on the line.
In 100BASE-TX mode, the device scrambles the data and transmits it to the network using
MLT-3 line code. The MLT-3 signals received from the network are de-scrambled and
decoded, and sent across the MII to the MAC.
In 100BASE-FX mode, the LXT973 Transceiver transmits and receives NRZI signals across
the LVPECL interface. An external 100BASE-FX transceiver module is required to complete
the fiber connection.
As shown in Figure 9, the MAC starts each transmission with a preamble pattern. As soon
as the LXT973 Transceiver detects the start of preamble, it transmits a J/K Start-of-Stream
Delimiter (SSD) symbol to the network. It then encodes and transmits the rest of the packet,
including the balance of the preamble, the Start-of-Frame Delimiter (SFD), packet data, and
CRC. Once the packet ends, the LXT973 Transceiver transmits the T/R End-of-Stream
Delimiter (ESD) symbol and returns to transmitting IDLE symbols.
Figure 9
100BASE-X Frame Format
64-Bit Preamble
(8 Octets)
P0
P1
Replaced by
/J/K/ code-groups
Start-of-Stream
Delimiter (SSD)
3.8.2
P6
Destination and Source
Address (6 Octets each)
SFD
DA
DA
SA
Packet Length
(2 Octets)
SA
L1
L2
Data Field
Frame Check Field InterFrame Gap / Idle Code
(Pad to minimum packet size)
(4 Octets)
(> 12 Octets)
D0
D1
Start-of-Frame
Delimiter (SFD)
Dn
CRC
I0
IFG
Replaced by
/T/R/ code-groups
End-of-Stream Delimiter (ESD)
100BASE-X Protocol Sublayer Operations
In the seven-layer OSI communications model, the LXT973 Transceiver is a Physical Layer
1 (PHY) device. The LXT973 Transceiver implements the Physical Coding Sublayer (PCS),
Physical Medium Attachment (PMA), and Physical Medium Dependent (PMD) sublayers of
the reference model defined by the IEEE 802.3u specification. The following paragraphs
discuss the LXT973 Transceiver operation from the reference model point of view.
3.8.3
PCS Sublayer
The Physical Coding Sublayer (PCS) provides the MII interface, as well as the 4B/5B
encoding/decoding function. For 100BASE-TX and 100BASE-FX operation, the PCS layer
provides IDLE symbols to the PMD-layer line driver as long as TXEN is de-asserted. For
10BASE-T operation, the PCS layer merely provides a bus interface and
serialization/de-serialization function. 10BASE-T operation does not use the 4B/5B
encoder.
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3.8.3.1
3.8 100 Mbps Operation
Preamble Handling
When the MAC asserts TXEN, the PCS substitutes a /J/K/ symbol pair, also known as the
Start-of-Stream Delimiter (SSD), for the first two nibbles received across the MII. The PCS
layer continues to encode the remaining MII data until TXEN is de-asserted. It then returns
to supplying IDLE symbols to the line driver.
The PCS layer performs the opposite function in the receive direction by substituting two
preamble nibbles for the SSD.
3.8.3.2
Dribble Bits
The LXT973 Transceiver handles dribble bits in all modes. If one through four dribble bits
are received, the nibble is passed across the MII, and padded with ones if necessary. If five
through seven dribble bits are received, the second nibble is not sent to the MII bus.
Figure 10
Protocol Sublayers
MII Interface
PCS
Sublayer
PMA
Sublayer
LXT973
Encoder/Decoder
Serializer/De-serializer
Link/Carrier Detect
LVPECL Interface
PMD
Sublayer
Scrambler/
De-scrambler
Fiber Transceiver
100BASE-TX
3.8.4
PMA Sublayer
3.8.4.1
Link Failure Override
100BASE-FX
The LXT973 Transceiver normally transmits 100 Mbps data packets or IDLE symbols only if
it detects that link is up, and transmits FLP bursts in auto-negotiation mode or IDLE symbols
in forced mode. Setting Register bit 16.14 = 1 overrides this function, allowing the LXT973
Transceiver to transmit data packets even when link is down. This feature is provided as a
diagnostic tool.
Note:
Auto-negotiation must be disabled to transmit data packets in the absence of link. If
auto-negotiation is enabled, the LXT973 Transceiver automatically begins transmitting FLP
bursts if the link goes down.
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3.8.4.2
3.8 100 Mbps Operation
Carrier Sense
For 100BASE-TX and 100BASE-FX links, a Start-of-Stream Delimiter (SSD) or /J/K/ symbol
pair causes assertion of carrier sense (CRS). An End-of-Stream Delimiter (ESD), or /T/R/
symbol pair causes de-assertion of CRS. The PMA layer also de-asserts CRS if IDLE
symbols are received without /T/R/. In this event, the RXER bit in the RX Status Frame is
asserted for one clock cycle when CRS is de-asserted.
3.8.4.3
Twisted-Pair PMD Sublayer
The twisted-pair Physical Medium Dependent (PMD) layer provides the signal scrambling
and descrambling, line coding and decoding (MLT-3), as well as receiving, polarity
correction, and baseline wander correction functions.
3.8.4.4
Scrambler/Descrambler
The purpose of the scrambler is to spread the signal power spectrum and further reduce
EMI using an 11-bit, non-data-dependent polynomial. The receiver automatically decodes
the polynomial whenever IDLE symbols are received.
The scrambler/de scrambler can be bypassed by setting Register bit 16.12 = 1. The
scrambler is automatically bypassed when the fiber port is enabled. Scrambler bypass is
provided for diagnostic and test support.
3.8.4.5
Baseline Wander Correction
The LXT973 Transceiver provides a baseline wander correction function which makes the
device robust under all network operating conditions. The MLT3 coding scheme used in
100BASE-TX is, by definition, “unbalanced.” This means that the DC average value of the
signal voltage can “wander” significantly over short time intervals (tenths of seconds). This
wander may cause receiver errors, particularly in less robust designs, at long-line lengths
(100 meters). The exact characteristics of the wander are completely data dependent.
The LXT973 Transceiver baseline wander correction characteristics allow the device to
recover error-free data while receiving worst-case “killer” packets over all cable lengths.
3.8.5
Fiber PMD Sublayer
The LXT973 Transceiver provides an LVPECL interface for connection to an external 3.3 V
or 5 V fiber-optic transceiver. (The external transceiver provides the PMD function for the
optical medium.) The LXT973 Transceiver uses a 125 Mbaud NRZI format for the fiber
interface, and does not support 10BASE-FL applications.
3.8.5.1
Far End Fault Indications
The LXT973 Transceiver Signal Detect pins independently detect signal faults from the
local fiber transceivers via the SD pins. The device also uses Register bit 1.4 to report
Remote Fault indications received from its link partner. The device ORs both fault conditions
to set Register bit 1.4. This bit is set once and cleared when read.
Either fault condition causes the LXT973 Transceiver to drop the link unless Forced Link
Pass is selected (Register bit 16.14 = 1). A link-down condition is then reported via status
bits.
In response to locally detected signal faults (SD activated by the local fiber transceiver), the
affected port can transmit the Far End Fault code if a fault code transmission is enabled by
Register bit 16.2.
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3.9 10 Mbps Operation
• When Register bit 16.2 = 1, transmission of the Far End Fault code is enabled. The
LXT973 Transceiver transmits Far End Fault code if fault conditions are detected by the
Signal Detect pins.
• When Register bit 16.2 = 0, the LXT973 Transceiver does not transmit Far End Fault
code. It continues to transmit IDLE code and may or may not drop link, depending on
the setting for Register bit 16.14.
The occurrence of a Far End Fault causes all transmission of data from the Reconciliation
Sublayer to stop and the Far End fault code to begin. The Far End Fault code consists of 84
“1s” followed by a single “0”, and is repeated until the Far End Fault condition is removed.
3.9
10 Mbps Operation
The LXT973 Transceiver operates as a standard 10BASE-T transceiver and supports all
the standard 10 Mbps functions. During 10BASE-T operation, the LXT973 Transceiver
transmits and receives Manchester-encoded data across the network link. When the MAC
is not actively transmitting data, the device sends out link pulses on the line.
In 10BASE-T mode, the polynomial scrambler/de-scrambler is inactive.
Manchester-encoded signals received from the network are decoded by the LXT973
Transceiver and sent across the MII to the MAC.
Note:
The LXT973 Transceiver does not support fiber connections at 10 Mbps.
3.9.1
Polarity Correction
The LXT973 Transceiver automatically detects and corrects for an inverted receive signal.
Reversed polarity is detected if eight inverted link pulses or four inverted End-of-Frame
(EOF) markers are received consecutively. If link pulses or data are not received by the
maximum receive time-out period, the polarity state is reset to a non-inverted state.
3.9.2
Dribble Bits
The LXT973 Transceiver device handles dribble bits in all modes. If one through four dribble
bits are received, the nibble is passed across the MII. If five through seven dribble bits are
received, the second nibble is not sent to the MII bus.
3.9.3
Link Test
The LXT973 Transceiver always transmits link pulses in 10BASE-T mode. When enabled,
the link test function monitors the connection for link pulses. Once link pulses are detected,
data transmission is enabled and remains enabled as long as either the link pulses or data
transmission continues. If link pulses stop, the data transmission is disabled.
If the link test function is disabled, the LXT973 Transceiver transmits to the connection
regardless of detected link pulses. The link test function is disabled by setting Register bit
16.14 = 1.
3.9.4
Link Failure
Link failure occurs if Link Test is enabled and link pulses or packets stop being received. If
this condition occurs, the LXT973 Transceiver returns to the auto-negotiation phase if
auto-negotiation is enabled.
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3.9.5
3.10 Monitoring Operations
Jabber
If a transmission exceeds the jabber timer, the LXT973 Transceiver disables the transmit
and loopback functions. The LXT973 Transceiver automatically exits jabber mode after the
unjab time has expired. This function is disabled by setting Register bit 16.10 = 1.
3.10
Monitoring Operations
3.10.1
Monitoring Auto-Negotiation
Auto-negotiation may be monitored as follows:
• Link Status Register bit 1.2 = 1 once the link is established.
• Additional bits in Register 1 can be used to determine the link operating conditions and
status (refer to Table 17 on page 67).
3.10.2
Per-Port LED Driver Functions
The LXT973 Transceiver incorporates three direct drive LEDs per port (LEDn_1, LEDn_2,
and LEDn_3). On power-up, all the LEDs light up for approximately one second after reset
de-asserts. Each LED may be configured to one of several different display modes using
the LED Configuration Pins, as shown in Table 10 on page 41.
The LED driver pins are open drain circuits (10 mA maximum current rating). If an LEDx_n
pin is unused, terminate with a 10K pull-up resistor. Figure 11 shows a typical LED
implementation. When configured for modes 2 or 4, the LEDs blink at the rate of 100 ms to
display multiple status.
Table 10 provides LED configurations for the LXT973 Transceiver.
Table 10
LED Configurations
LED_CFG0
0
LED_CFG1
0
1
0
1
1
Figure 11
0
1
LEDn_1
LEDn_2
LEDn_3
Speed
Link
Duplex
Speed
Link/Activity
Duplex/Collision
Link
Receive
Transmit
Speed
Link/MII Isolate
Duplex/Collision
Typical LED Implementation
VLED
220
LEDx_n
pin
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4.0
Application Information
4.1
Design Recommendations
4.0 Application Information
The LXT973 Transceiver is designed to comply with IEEE 802.3 requirements to provide
outstanding receive Bit Error Rate (BER), and long-line-length performance. To achieve
maximum performance from the LXT973 Transceiver, attention to detail and good design
practices are required. Refer to the LXT973 Transceiver Design and Layout Guide for
detailed design and layout information.
4.1.1
General Design Guidelines
Adherence to generally accepted design practices is essential to minimize noise levels on
power and ground planes. Up to a maximum noise level of 50 mV is considered acceptable.
High-frequency switching noise can be reduced, and its effects eliminated, by following
these simple guidelines throughout the design:
• Fill in unused areas of the signal planes with solid copper and attach them with vias to a
VCC or ground plane that is not located adjacent to the signal layer.
• Use ample bulk and de-coupling capacitors throughout the design (a value of 0.01 F is
recommended for de-coupling caps).
• Provide ample power and ground planes.
• Provide termination on all high-speed switching signals and clock lines.
• Provide impedance matching on long traces to prevent reflections.
• Route high-speed signals next to a continuous, unbroken ground plane.
• Filter and shield DC-to-DC converters, oscillators, etc.
• Do not route any digital signals between the LXT973 Transceiver and the RJ-45
connectors at the edge of the board.
• Do not extend any circuit power and ground planes past the center of the magnetics or
to the edge of the board. Use this area for chassis ground, or leave it void.
4.1.2
Power Supply Filtering
Power supply ripple and digital switching noise on the VCC plane may cause EMI problems
and degrade line performance. To minimize ground noise as much as possible, use good
general techniques and filter the VCC plane. It is difficult to predict in advance the
performance of any design, although certain factors greatly increase the risk of having
problems:
• Poorly-regulated or over-burdened power supplies.
• Wide data busses (32-bits+) running at a high clock rate.
• DC-to-DC converters.
Cortina recommends filtering the power supply to the analog VCC pins of the LXT973
Transceiver. This has two benefits. First, it keeps digital switching noise out of the analog
circuitry inside the LXT973 Transceiver, helping with line performance. Second, if the VCC
planes are laid out correctly, digital switching noise is kept away from external connectors,
reducing EMI problems.
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4.1 Design Recommendations
The recommended implementation is to break the VCC plane into two sections. The digital
section supplies power to the VCCD and VCCIO pins of the LXT973 Transceiver. The
analog section supplies power to the VCCR, VCCT, VCCPECL pins. The break between the
two planes should run underneath the device. In designs with more than one LXT973
Transceiver device, a single continuous analog VCC plane can be used to supply them all.
The digital and analog VCC planes should be joined at one or more points by ferrite beads.
The beads should produce at least a 100 impedance at 100 MHz. Beads should be placed
so that current flow is evenly distributed. The maximum current rating of the beads should
be at least 150% of the current that is actually expected to flow through them. A bulk cap
(2.2 -10 F) should be placed on each side of each bead. In addition, a high-frequency
bypass cap (0.01 F) should be placed near each analog VCC pin.
4.1.3
Power and Ground Plane Layout Considerations
Great care needs to be taken when laying out the power and ground planes.
• Follow the guidelines in the LXT973 Transceiver Design and Layout Guide for locating
the split between the digital and analog VCC planes.
• Keep the digital VCC plane away from the DIFAP/N_n and DIFBP/N_n signals, the
magnetics, and the RJ-45 connectors.
• Place the layers so that the DIFAP/N_n and DIFBP/N_n signals can be routed near or
next to the ground plane.
4.1.3.1
Chassis Ground
For ESD reasons, it is a good design practice to create a separate chassis ground that
encircles the board and is isolated via moats and keep-out areas from all circuit-ground
planes and active signals. Chassis ground should extend from the RJ-45 connectors to the
magnetics, and can be used to terminate unused signal pairs (Bob Smith termination). In
single-point grounding applications, provide a single connection between chassis and circuit
grounds with a 2 kV isolation capacitor. In multi-point grounding schemes (chassis and
circuit grounds joined at multiple points), provide 2 kV isolation to the Bob Smith
termination.
4.1.4
MII Terminations
Series termination resistors are generally required. Keep all traces orthogonal and as short
as possible. Whenever possible, route the clock traces evenly between the longest and
shortest data routes. This minimizes round-trip, clock-to-data delays and allows a larger
margin to the setup and hold requirements. Please refer to the LXT973 Transceiver Design
and Layout Guide for series resistor values.
4.1.5
The Fiber Interface
The fiber interface consists of an LVPECL transmit and receive pair to an external
fiber-optic transceiver. Both 3.3 V fiber-optic transceivers and 5 V fiber-optic transceivers
can be used with the LXT973 Transceiver. See the 100BASE-FX Fiber Optic
Transceivers-Connecting a PECL/LVPECL Interface Application Note (document number
250781) for detailed information on fiber interface designs and recommendations for
Cortina PHYs.
The following should occur in 3.3 V fiber transceiver applications as shown in Figure 14:
• The transmit pair should be AC-coupled with 2.5 V supplies and re-biased to
3.3 VLVPECL levels
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4.1 Design Recommendations
• The transmit pair should contain a balance offset in the pull-up resistors to prevent
PHY-to-fiber transceiver crosstalk amplification in power-down, loopback, and reset
states (see fiber interface application note)
• The receive pair should be DC-coupled with an emitter current path for the fiber
transceiver
• The signal detect pin should be DC-coupled with an emitter current path for the fiber
transceiver
Refer to the fiber transceiver manufacturers’ recommendations for termination circuitry.
Figure 14, Recommended LXT973 Transceiver Transceiver-to-3.3 V Fiber Transceiver
Interface Circuitry, on page 48 shows a typical example of an LXT973 Transceiver-to-3.3 V
fiber transceiver interface.
The following occurs in 5 V fiber transceiver applications as shown in Figure 15,
Recommended LXT973 Transceiver-to-5 V Fiber Transceiver Interface Circuitry, on
page 49:
• The transmit pair should be AC-coupled and re-biased to 5 V PECL input levels
• The transmit pair should contain a balance offset in the pull-up resistors to prevent
PHY-to-fiber transceiver crosstalk amplification in power-down, loopback, and reset
states (see fiber interface application note)
• The receive pair should be AC-coupled with an emitter current path for the fiber
transceiver and re-biased to 1.2 V
• The signal detect pin on a 5 V fiber transceiver interface should use the logic translator
circuitry as shown in Figure 16, ON Semiconductor* Triple PECL-to-LVPECL Logic
Translator, on page 50.
Refer to the fiber transceiver manufacturers’ recommendations for termination circuitry.
Figure 15 shows a typical example of an LXT973 Transceiver-to-5 V fiber transceiver
interface, while Figure 16 shows the interface circuitry for the logic translator.
4.1.6
Twisted-Pair Interface
Use the following standard guidelines for a twisted-pair interface:
• Place the magnetics as close as possible to the LXT973 Transceiver.
• Keep transmit pair traces as short as possible; both traces should have the same
length.
• Avoid vias and layer changes as much as possible.
• Keep the transmit and receive pairs apart to avoid cross-talk.
• Route the transmit pair adjacent to a ground plane. The optimum arrangement is to
place the transmit traces two to three layers from the ground plane with no intervening
signals.
• Improve EMI performance by filtering the TPO center tap. A single ferrite bead rated at
100 mA may be used to supply center tap current to all ports.
4.1.7
Magnetics Information
The LXT973 Transceiver requires a 1:1 ratio for the receive transformers and a 1:1 ratio for
the transmit transformers. The transformer isolation voltage should be rated at 2 kV to
protect the circuitry from static voltages across the connectors and cables. The LXT973
Transceiver is a current-driven transceiver that requires an external voltage (center tap) to
drive the transmit signal. To support LXT973 Transceiver auto MDI/MDIX functionality, the
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4.1 Design Recommendations
magnetic must provide a center tap for both transmit and receive magnetic windings, with
both connected to VCCT (see Figure 13 on page 47). When using the auto MDI/MDIX
function, select a magnetic so that both transmit and receive windings are matched or
balanced (refer to the LXT973 Transceiver Design and Layout Guide – document number
249631). Refer to Table 11 for transformer requirements. Before committing to a specific
component, designers should contact the manufacturer for current product specifications,
and validate the magnetics for the specific application.
Table 11
Magnetics Requirements
Parameter
Min
Nom
Max
Units
Test Condition
Rx turns ratio
–
1:1
–
–
–
Tx turns ratio
–
1:1
–
–
–
Insertion loss
0.0
0.6
1.1
dB
–
Primary inductance
350
–
–
H
–
2
–
–
kV
–
40
–
–
dB
.1 to 60 MHz
35
–
–
dB
60 to 100 MHz
-16
–
–
dB
30 MHz
-10
–
–
dB
80 MHz
Transformer
isolation
Differential to
common mode
rejection
Return Loss
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4.2
4.2 Typical Application Circuits
Typical Application Circuits
Figure 12 through Figure 17 on page 50 show typical application circuits for the
LXT973 Transceiver.
Figure 12
Power and Ground Supply Connections
SGND
GNDR/GNDT
0.01 F
VCCR/VCCT
10 F
Analog Supply Plane
LXT973
Ferrite
Bead
Digital Supply Plane
VCCD
+
10 F
+2.5 V
0.01 F
GNDD
0.01 F
VCCIO
+ 2.5 V
or +3.3 V
VCCPECL
+2.5 V
or +3.3 V
GNDPECL
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Figure 13
4.2 Typical Application Circuits
Typical Twisted-Pair Interface
Notes:
1. The 100 transmit load termination resistor typically required is integrated in the LXT973 Transceiver.
2. The 100 receive load termination resistor typically required is integrated in the LXT973 Transceiver.
3. Recommended 0.1 F capacitor to improve EMI performance.
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Figure 14
4.2 Typical Application Circuits
Recommended LXT973 Transceiver Transceiver-to-3.3 V Fiber Transceiver
Interface Circuitry
Note:
1. Refer to the transceiver manufacturers’ recommendations for termination circuitry.
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Figure 15
4.2 Typical Application Circuits
Recommended LXT973 Transceiver-to-5 V Fiber Transceiver Interface Circuitry
Notes:
1. Refer to the transceiver manufacturers’ recommendations for termination circuitry.
2. See Figure 16 for recommended logic translator interface circuitry.
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Figure 16
4.2 Typical Application Circuits
ON Semiconductor* Triple PECL-to-LVPECL Logic Translator
5V
0.01 F
0.01 F
5V
3.3 V
ON Semiconductor*
82
PECL Input
Signal
(5 V Fiber
Txcvr)
130
1
Vcc
2
D0
__
D0
VBB PECL
3
4
5
6
7
8
9
10
Vcc
D1
__
D1
VBB PECL
20
Q0 19
__
Q0 18
LVCC
17
130
82
3.3 V
Q1 16
__
Q1 15
LVCC
14
D2
__
D2
Q2
__
Q2
13
GND
Vcc 11
12
LVPECL Output
Signal
(LXT973)
0.01 F
3.3 V
130
MC100LVEL92
82
Figure 17
Typical MII Interface
TXEN
TXER
TXD
TXCLK
MAC
RXDV
RXER
RXD
LXT973
Transformer
RXCLK
RJ-45
CRS
COL
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4.3
4.3 Initialization
Initialization
At power-up or reset, the LXT973 Transceiver performs the initialization as shown in
Figure 18 on page 51. When the MDDISn pin is High, the LXT973 Transceiver enters
Manual Control Mode for that port. When MDDISn is Low, MDIO Control Mode is enabled
for that port. Mode control selection is provided via the MDDISn pin as shown in Table 12
on page 52.
4.4
MDIO Control Mode
In the MDIO Control mode, the LXT973 Transceiver uses the Hardware Control Interface to
set up initial (default) values of the MDIO registers. Once initial values are set, bit control
reverts to the MDIO interface.
4.5
Manual Control Mode
In the Manual Control Mode, LXT973 Transceiver disables direct write operations to the
MDIO registers on the MDIO interface. The Hardware Control Interface is monitored during
Reset to set up the MDIO registers.
Figure 18
Initialization Sequence
Power-up or Reset
Read H/W Control
Interface
Initialize MDIO
Registers
MDIO Control Mode
MDDISn = 0
Manual Control Mode
MDDISn = 1
MDDIS
Pass Control to
MDIO Interface
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Disable MDIO
Writes
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Table 12
4.5 Manual Control Mode
Mode Control Settings
MDDISn
RESET
PWRDWN
Mode
Low
High
Low
MDIO Control
High
High
Low
Manual Control
-
Low
Low
Reset - Latch default configuration
-
-
High
Low Power and reset mode
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5.0
5.0 Configuration
Configuration
When the LXT973 Transceiver is first powered on, reset, or encounters a link-down state, it
must determine the line speed and operating conditions to use for the network link. The
LXT973 Transceiver first checks the MDIO registers (initialized via the Hardware Control
interface or written by software) for operating instructions. Using these mechanisms, the
user can command the LXT973 Transceiver to do one of the following:
• Forced 100BASE-FX operation
• Forced twisted-pair link operation to:
— 100BASE-TX, full-duplex
— 100BASE-TX, half-duplex
— 10BASE-T, full-duplex
— 10BASE-T, half-duplex
• Allow auto-negotiation/parallel-detection.
In forced twisted-pair link operation, the LXT973 Transceiver immediately begins operating
the network interface as commanded. In the last case, the LXT973 Transceiver begins the
auto-negotiation/parallel-detection process.
Several pins are used to configure the LXT973 Transceiver device. Table 13 summarizes
the available manual configurations to the port. Usually these pins are decodes of chip pins.
This is useful for manual configuration.
Table 13
Configuration Settings (Hardware Control Interface) (Sheet 1 of 2)
FIBER_TPn
AUTO_NEGx
SPEEDx
Low
–
–
Low
100BASE-FX is enabled in half-duplex mode.
Auto-negotiation is disabled
Low
–
–
High
100BASE-FX is enabled in full-duplex mode.
Auto-negotiation is disabled.
High
High
High
High
AUTO_NEG is enabled. All capabilities are
advertised.
Register bits 4.8, 4.7, 4.6 and 4.5 are all set to 1.
Low
AUTO_NEG is enabled. Only 100 Mbps
capabilities are advertised.
Register bits 4.8 and 4.7are set to 1. Register bits
4.6 and 4.5 are cleared to 0.
High
High
High
DUPLEXx
Mode
High
High
Low
High
AUTO_NEG is enabled. Only 10 Mbps
capabilities are advertised.
Register bits 4.8 and 4.7 are cleared to 0.
Register bits 4.6 and 4.5 are set to 1.
High
High
Low
Low
AUTO_NEG is enabled. Only half-duplex
capabilities are advertised.
Register bits 4.7 and 4.5 are set 1. Register bits
4.8 and 4.6 are cleared to 0.
High
Low
High
High
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 100 Mbps full-duplex operation.
1. These pins also set the default values for Registers 0 and 4 accordingly.
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Datasheet
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23 August 2011
Table 13
5.0 Configuration
Configuration Settings (Hardware Control Interface) (Sheet 2 of 2)
FIBER_TPn
AUTO_NEGx
SPEEDx
DUPLEXx
Mode
High
Low
High
Low
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 100 Mbps half-duplex operation.
High
Low
Low
High
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 10 Mbps full-duplex operation.
High
Low
Low
Low
AUTO_NEG is disabled. LXT973 Transceiver port
x is forced to 10 Mbps half-duplex operation.
1. These pins also set the default values for Registers 0 and 4 accordingly.
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Datasheet
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23 August 2011
6.0
6.0 Auto Negotiation
Auto Negotiation
The LXT973 Transceiver PHY supports the IEEE 802.3u auto-negotiation scheme with
Next Page capability. Next Page exchange utilizes Register 7 to send information and
Register 8 to receive them. Next Page exchange can only occur if both ends of the link
advertise their ability to exchange Next Pages.
The LXT973 Transceiver is configured to make Next Page exchange easier for software.
When a Base Page or Next Page is received, the Page Received Register bit 6.1 remains
set until read. When Register bit 6.2 (Next Page Able) is received, it stays set until read.
This bit is cleared whenever a new negotiation occurs. This prevents the user from reading
an old value in Register 6 and assuming there is valid information in Registers 5 and 8.
Additionally, Register 6 contains a new bit (Register bit 6.5) that indicates when the current
Received Page is the Base Page. This information is useful for recognizing when next
pages must be re-sent due to the start of a new negotiation process. Register bit 16.1 and
the Page Received bit (Register bit 6.1) are also cleared upon reading Register 6.
.
Next Page
Encoding
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
OUI tagged
Message
1
a
1
0
t
0
0
0
0
0
0
0
0
1
0
1
user page 1
1
a
0
0
t
3.10
3.11
3.12
3.13
3.14
3.15
2.0
2.1
2.2
2.3
2.4
user page 2
1
a
0
0
t
2.5
2.6
2.7
2.8
2.9
2.10
2.11
2.12
2.13
2.14
2.15
user page 3
1
a
0
0
t
0
0
L.8
L.7
L.6
L.5
L.4
L.3
L.2
L.1
L.0
user page 4
1
a
0
0
t
L.10
L.9
L.8
L.7
L.6
L.5
L.4
L.3
L.2
L.1
L.0
1. a is the acknowledge bit; t is the toggle bit; L is the LFSR.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
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23 August 2011
7.0
7.0 Auto-MDI/MDIX
Auto-MDI/MDIX
Twisted-pair Ethernet PHYs must be correctly configured for MDI or MDIX operation to inter
operate. This has historically been accomplished using special patch cables, magnetics
pinouts, or PCB wiring.
The LXT973 Transceiver PHY supports the automatic MDI/MDIX configuration originally
developed for 1000BASE-T and standardized in IEEE 802.3u, section 40. A manual
configuration (for example, non-automatic) is still possible using configuration register bits.
The automatic MDI/MDIX function is not intended for fiber applications.
The automatic MDI/MDIX state machine facilitates switching of the twisted-pair input signals
(DIFBP/N_0 and DIFBP/N_1) with the twisted-pair output signals (DIFAP/N_0 and
DIFAP/N_1), respectively, prior to the auto-negotiation mode of operation. This is done so
that FLPs can be transmitted and received in compliance with Clause 28, Auto-Negotiation
specifications.
The correct polarization of the crossover circuit is determined by an algorithm that controls
the switching function. This algorithm uses an 11-bit Linear Feedback Shift Register (LFSR)
to create a pseudo-random sequence that each end of the link uses to determine its
proposed configuration.
After selecting MDI or MDIX, the node waits for a specified amount of time, while evaluating
its receive channel, to determine whether the other end of the link is sending link pulses or
PHY-dependent data. If link pulses or PHY-dependent data are detected, it remains in that
configuration. If link pulses or PHY-dependent data are not detected, it increments its LFSR
and makes a decision to switch based on the value of the next bit. The state machine does
not move from one state to another while link pulses are being transmitted.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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23 August 2011
8.0
8.0 100 Mbps Operation
100 Mbps Operation
The MAC passes data to the LXT973 Transceiver over the MII. The LXT973 Transceiver
encodes and scrambles the data, then transmits it using MLT-3 (for
100BASE-TX-over-copper), or NRZI signaling (for 100BASE-FX-over-fiber). The LXT973
Transceiver descrambles and decodes MLT-3 data received from the network. When the
MAC is not actively transmitting data, the
LXT973 Transceiver sends out IDLE symbols on the line.
As shown in Figure 19 on page 57, the MAC starts each transmission with a preamble
pattern. When TXEN is asserted, the LXT973 Transceiver transmits a /J/K/ symbol to the
network (Start of Stream Delimiter or SSD). It then encodes and transmits the rest of the
packet, including the balance of the preamble, the SFD (Start of Frame Delimiter), packet
data, and CRC. Once the packet ends, the LXT973 Transceiver transmits the /T/R/symbol
(End-of-Stream Delimiter (ESD)) and then returns to transmitting IDLE symbols.
The encoder translates the 4-bit nibbles into 5-bit symbols, which are sent over the
100BASE-TX connection. A fifth bit is provided on pins TXER0 and TXER1 during symbol
mode to allow a 5-bit symbol to be sent across the MII interface. The 5B encoder is
bypassed in symbol mode.
Figure 20 on page 57 shows the data conversion flow from nibbles to symbols.
8.1
Displaying Symbol Errors
The PHY provides the MAC with an indication of errors that occur during the receive
process. This output is called RXER. It is possible to map the symbol error detection output
to the RXER pin using Register bit 26.9. In normal mode (Register bit 26.9 = 0), the RXER
output is active per the IEEE 802.3 standard. When this register bit = 1, the RXER output
goes active only when a symbol error is detected. This provides a quick measure of bit error
rate.
Figure 19
100BASE-TX Frame Format
64-Bit Preamble
(8 Octets)
P0
P1
Replaced by
/J/K/ code-groups
Start-of-Stream
Delimiter (SSD)
Figure 20
P6
Destination and Source
Address (6 Octets each)
SFD
DA
DA
SA
Packet Length
(2 Octets)
SA
L1
Data Field
Frame Check Field InterFrame Gap / Idle Code
(Pad to minimum packet size)
(4 Octets)
(> 12 Octets)
L2
D0
D1
Dn
CRC
IFG
I0
Replaced by
/T/R/ code-groups
End-of-Stream Delimiter (ESD)
Start-of-Frame
Delimiter (SFD)
100BASE-TX Data Path
Standard MII Mode Data Flow
D0
D1
+1
Parallel
to
Serial
D0 D1 D2 D3
D2
D3
Serial
to
Parallel
4B/5B
5B/4B
0
Scramble
S0
S1
S2
S3
S4
DeScramble
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
MLT3
0
0
-1
Transition = 1.
No Transition = 0.
All transitions must follow
pattern: 0, +1, 0, -1, 0, +1...
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23 August 2011
8.1.1
8.1 Displaying Symbol Errors
Scrambler Seeding
Once the transmit data (or IDLE symbols) are properly encoded, they are scrambled to
further reduce EMI and to spread the power spectrum using an 11-bit scrambler seed.
Five-seed bits are determined by global PHY address, and six-seed bits are selected by the
port number. One of the 11 bits must be a “1”.
8.1.2
Scrambler Bypass
The scrambler can be bypassed by setting Register bit 16.12 = 1. Scrambler Bypass is
provided for diagnostic and test support.
The descrambler cannot be bypassed. The 100BASE-TX receiver in the LXT973
Transceiver will not converge to unscrambled idle, so a descrambler bypass is useless.
8.1.3
100BASE-T Link Failure Criteria and Override
The LXT973 Transceiver normally transmits 100Mbps data packets only if it detects the link
is up, and transmits only Idle symbols or FLP bursts if the link is not up. Setting Register bit
16.14 = 1 overrides this function, allowing the LXT973 Transceiver to transmit data packets
even when the link is down. This feature is provided as a diagnostic tool. Note that
auto-negotiation must be disabled to transmit data packets in the absence of link. If
auto-negotiation is enabled, the
LXT973 Transceiver automatically begins transmitting FLP bursts if the link goes down.
8.1.4
Baseline Wander Correction
The LXT973 Transceiver provides a baseline wander correction function which makes the
device robust under all network operating conditions. The MLT3 coding scheme used in
100BASE-TX is by definition “unbalanced”. This means that the DC average value of the
signal voltage can “wander” significantly over short time intervals (tenths of seconds). This
wander can cause receiver errors, particularly at long line lengths (160 meters). The exact
characteristics of the wander are completely data dependent. “Killer Packets” have been
created that exhibit worst case baseline wander characteristics. The LXT973 Transceiver
baseline wander correction characteristics allow the LXT973 Transceiver to recover
error-free data, even at long line lengths.
8.1.5
Programmable Tx Slew Rate
The LXT973 Transceiver device supports a slew rate mechanism where one of four
pre-selected slew rates can be used, set either through the input pins or through Register
27.
Figure 21
100BASE-TX Reception with no Errors
RXCLK
RXDV
RXD
preamble SFD SFD
DA
DA
DA
DA
CRC
CRC
CRC
CRC
RXER
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23 August 2011
Figure 22
8.1 Displaying Symbol Errors
100BASE-TX Reception with Invalid Symbol
RXCLK
RXDV
RXD
preamble SFD SFD
DA
DA
XX
XX
XX
XX
XX
XX
XX
XX
XX
XX
RXER
Figure 23
100BASE-TX Transmission with no Errors
TXCLK
TXEN
TXD
P
R
E
A
M
B
L
E
DA
DA DA DA DA
DA DA DA
DA
CRS
COL
Figure 24
100BASE-TX Transmission with Collision
TXCLK
TXEN
TXD
P
R
E
A
M
B
L
E
JAM
JAM
JAM
JAM
CRS
COL
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23 August 2011
9.0
9.0 Fiber Interface
Fiber Interface
The fiber ports of the LXT973 Transceiver are designed to connect to common industry
standard fiber modules. The fiber ports incorporate LVPECL receivers and drivers, allowing
for seamless integration. The LXT973 Transceiver provides a separate pin for the signal
detect function. If designers wish to implement this feature, they need to provide a
separate signal for this function. If the signal quality starts to degrade, this pin is essentially
used to detect a remote fault condition and signals it accordingly. Loss of signal quality also
blocks any fiber data from being received and causes a loss of link.
The remote fault code consists of 84 consecutive ones followed by a single zero. This
pattern must be repeated at least three times. The LXT973 Transceiver transmits the
remote fault code a minimum of three times if all the following conditions are true:
1. Signal Detect indicates no signal
2. Far End Fault Enable bit (Register bit 16.2 Test Register) is set
3. Auto-negotiation is not enabled
4. Fiber mode is selected
The remote fault (Register bit 1.4) is set when the LXT973 Transceiver is either actively
transmitting a remote fault or if the LXT973 Transceiver has received a remote fault from its
link partner. The transmitted remote fault can come from the above conditions if
auto-negotiation is not enabled. If auto-negotiation is enabled, the transmitted remote fault
condition is indicated by Register bit 4.13 in the Auto-Negotiation Advertisement Register.
Likewise, a remote fault can be set by the LXT973 Transceiver link partner in two ways. If
auto-negotiation is enabled, Register bit 5.13 is set in the Auto-Negotiation Link Partner
Ability Register. If auto-negotiation is disabled, the remote fault condition is set by the
remote fault code being received on the fiber inputs.
A register bit has been provided that either selects normal, unscrambled fiber data, or
scrambles the transmitted fiber data (Register bit 26.10).
When in loopback mode, the remote fault condition is not transmitted.
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23 August 2011
10.0
10.0 10 Mbps Operation
10 Mbps Operation
The LXT973 Transceiver operates as a standard 10 Mbps transceiver. Data transmitted by
the MAC as a 4-bit nibble is serialized, Manchester-encoded, and transmitted on the
twisted-pair outputs
(DIFAP/N_0 and DIFAP/N_1). Received data is decoded, de-serialized into 4-bit nibbles,
and passed on RXD[3:0] to the MAC across the MII. The LXT973 Transceiver supports all
the standard 10 Mbps functions.
10.1
Link Test
In 10 Mbps mode, the LXT973 Transceiver always transmits link pulses. If the Link Test
Function is enabled, it monitors the connection for link pulses. Once it detects two to seven
link pulses, data transmission is enabled and remains enabled as long as the link pulses or
data reception continues. If the link pulses stop, the data transmission is disabled.
If the Link Test function is disabled, the LXT973 Transceiver may transmit packets
regardless of detected link pulses. The Link Test function can be disabled by setting Port
Configuration Register bit 16.14.
10.2
10Base-T Link Failure Criteria and Override
Link failure occurs if Link Test is enabled and link pulses stop being received. If this
condition occurs, the LXT973 Transceiver returns to the auto-negotiation phase if
auto-negotiation is enabled. If the Link Integrity Test function is disabled by setting the Port
Configuration Register bit 16.14, the LXT973 Transceiver transmits packets, regardless of
link status.
10.3
SQE (Heartbeat)
By default, the SQE (heartbeat) function is disabled on the LXT973 Transceiver. To enable
this function, set Register bit 16.9 = 1. When this function is enabled, the LXT973
Transceiver asserts its COL output for
5 - 15 bit times after each packet. See Figure 35 on page 87 for SQE timing parameters.
10.4
Jabber
If the MAC begins a transmission that exceeds the jabber timer, the LXT973 Transceiver
disables the transmit and loopback functions and enables the COL pin. The LXT973
Transceiver automatically exits jabber mode after 250 - 750 ms. This function can be
disabled by setting Register bit 16.10 = 1. See Figure 36 on page 87 for jabber timing
parameters.
10.5
Polarity Correction
The LXT973 Transceiver automatically detects and corrects for the condition where the
receive signal (DIFBP/N_0 and DIFBP/N_1) is inverted. Reversed polarity is detected if 8
inverted link pulses, or 4 inverted end-of-frame markers, are received consecutively. If link
pulses or data are not received for 96-130 ms, the polarity state is reset to a non-inverted
state.
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23 August 2011
10.6
10.6 Dribble Bits
Dribble Bits
The LXT973 Transceiver device handles dribbles bits. If one to four dribble bits are
received, the nibble is passed across the interface. The data passed across is padded with
ones, if necessary. If five to seven dribble bits are received, the second nibble is not sent to
the MII bus. This ensures that dribble bits one through seven will not cause a MAC to
discard the frame due to a CRC error. (In 10 Mbps serial mode, all bits are simply passed
across the interface unmodified.)
10.7
Transmit Polarity Control
The LXT973 Transceiver allows control over 10BASE-T transmit signal polarity for
simplified integration. In combination with selectable MDI/MDIX mode and automatic
polarity detection, this allows maximum flexibility in pinout definition. (Either of the twisted
pairs may be transmit or receive, and either side of each twisted pair may be set to positive
or negative.)
10.8
PHY Address
The LXT973 Transceiver provides four bits to set the PHY address.The least significant bit
is fixed internally with Port 1 always being one address higher than Port 0.
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23 August 2011
11.0 Clock Generation
11.0
Clock Generation
11.1
External Oscillator
Figure 25 through Figure 27 on page 64 illustrate the different frequencies of clock for
10BASE-T and 100BASE-TX in the LXT973 Transceiver.
Figure 25
MII 10BASE-T DTE Mode Auto-Negotiation
2.5 MHz Clock During Auto-Negotiation and 10BASE-T Data / Idle
TXCLK
(Sourced by LXT973)
2.5 MHz Clock During Auto-Negotiation and 10BASE-T Data / Idle
RXCLK
(Sourced by LXT973)
REFCLK
(25 MHz Oscillator Clock)
Figure 26
100BASE-T DTE Mode Auto-Negotiation
2.5 MHz Clock During Auto-Negotiation
25 MHz During 100BASE-T Mode
TXCLK
(Sourced by LXT973)
2.5 MHz Clock During Auto-Negotiation
25 MHz During 100BASE-T Mode
RXCLK
(Sourced by LXT97)
REFCLK
(25 MHz Oscillator Clock)
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
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23 August 2011
Figure 27
11.1 External Oscillator
Link Down Clock Transition
Link Down condition/Auto Negotiate Link Up
RXCLK
TXCLK
Any Clock
2.5 MHz Clock
Clock transition time will not exceed
2.5x the destination clock period.
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LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
12.0
12.0 Register Definitions
Register Definitions
The LXT973 Transceiver register set includes 16 registers per port. Refer to Table 14 for a
complete register listing.
Base Registers 0 through 8 are defined in accordance with the “Reconciliation Sublayer and
Media Independent Interface” and “Physical Layer Link Signaling for 10/100 Mbps
Auto-Negotiation” sections of the IEEE 802.3 specification.
Additional registers are defined in accordance with the IEEE 802.3 specification for adding
unique chip functions.
Table 14
Common Register Set
Address
Table 15
Register Name
Bit Definitions
0
Control Register
Refer to Table 16 on page 66
1
Status Register
Refer to Table 17 on page 67
2
PHY Identification Register 1
Refer to Table 18 on page 68
3
PHY Identification Register 2
Refer to Table 19 on page 68
4
Auto-Negotiation Advertisement Register
Refer to Table 20 on page 69
5
Auto-Negotiation Link Partner Base Page Ability Register Refer to Table 21 on page 70
6
Auto-Negotiation Expansion Register
Refer to Table 22 on page 71
7
Auto-Negotiation Next Page Transmit Register
Refer to Table 23 on page 71
8
Auto-Negotiation Link Partner Received Next Page
Register
Refer to Table 24 on page 72
16
Port Configuration Register
Refer to Table 25 on page 72
27
Special Function Register
Refer to Table 26 on page 73
Register Bit Descriptions
Bit Type
R/W
Description
Read and Write capable
RO
Read Only
WO
Write Only
AC
Auto Clear on Read
LHR
Latched from external pins on reset
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
249426, Revision 7.0
23 August 2011
Table 16
12.0 Register Definitions
Control Register (Address 0)
Bit
Name
Description
Type1,2
Default
0.15
RESET
1 = PHY reset
0 = Normal operation
R/W
AC
0
Note 2
0.14
Loopback
1 = Enable loopback mode
0 = Disable loopback mode
R/W
0
0.13
Speed Selection
(LSB)
0.6
1
1
0
0
0.13
1 = Reserved
0 = 1000 Mbps (not allowed)
1 = 100 Mbps
0 = 10 Mbps
R/W
LHR
Note 3
0.12
Auto-Negotiation
Enable
1 = Enable Auto-Negotiation Process
0 = Disable Auto-Negotiation Process
R/W
LHR
Note 3
0.11
Power-Down
1 = Power-Down
0 = Normal operation
R/W
0
0.10
Isolate
1 = Electrically isolate PHY from MII
0 = normal operation
R/W
0
Note 4
0.9
Restart
Auto-Negotiation
1 = Restart Auto-Negotiation Process
0 = Normal operation
R/W
AC
0
0.8
Duplex Mode
1 = Full-duplex
0 = Half-duplex
R/W
LHR
Note 3
0.7
Collision Test
1 = Enable COL signal test
0 = Disable COL signal test
R/W
0
Speed Selection
(MSB)
0.6
1
1
0
0
R/W
00
Reserved
Write as 0, ignore on Read
R/W
000000
0.6
0.5:0
0.13
1 = Reserved
0 = 1000 Mbps (not allowed)
1 = 100 Mbps
0 = 10 Mbps
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. During a hardware reset, all LHR information is latched in from the pins. During a software reset (Register
bit 0.15), the LHR information is not re-read from the pins. This information reverts back to the information
that was read in during the hardware reset. During a hardware reset, register information is unavailable for
1 ms after de-assertion of the reset. During a software reset (Register bit 0.15) the registers are available
for reading. The reset bit should be polled to see when the part has completed reset.
3. LHR = Latched on Hardware Reset. Register bits 0.12, 0.13 and 0.8 are initialized based on the pin
configuration value.
4. The Isolate function (Register bit 0.10) three-states all port MAC interface outputs. On the input side,
TXEN and TXER are ignored.
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Datasheet
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23 August 2011
Table 17
12.0 Register Definitions
Status Register (Address 1)
Bit
Name
Description
Type1,2
Default
1.15
100BASE-T4
1=
0=
PHY able to perform 100BASE-T4
PHY not able to perform 100BASE-T4
RO
0
1.14
100BASE-X
Full- Duplex
1=
0=
PHY able to perform full-duplex 100BASE-X
PHY not able to perform full-duplex 100BASE-X
RO
1
1.13
100BASE-X
Half- Duplex
1=
0=
PHY able to perform half-duplex 100BASE-X
PHY not able to perform half-duplex
100BASE-X
RO
1
1.12
10 Mbps
Full-Duplex
PHY able to operate at 10 Mbps in full-duplex
mode
PHY not able to operate at 10 Mbps full-duplex
mode
RO
1
PHY able to operate at 10 Mbps in half-duplex
mode
PHY not able to operate at 10 Mbps in
half-duplex
RO
1
1.11
10 Mbps
Half-Duplex
1=
0=
1=
0=
1.10
100BASE-T2
Full- Duplex
1=
0=
PHY able to perform full-duplex 100BASE-T2
PHY not able to perform full-duplex
100BASE-T2
RO
0
1.9
100BASE-T2
Half- Duplex
1=
0=
PHY able to perform half-duplex 100BASE-T2
PHY not able to perform half-duplex
100BASE-T2
RO
0
1.8
Extended Status
1=
0=
Extended status information in Register 15
No extended status information in Register 15
RO
0
1.7
Reserved
0=
Write as 0, ignore on read
RO
0
1=
PHY accepts management frames with
preamble
suppressed
RO
0
0=
PHY will not accept management frames with
preamble suppressed
RO
0
RO/LH
Note 2
0
RO
1
1.6
MF Preamble
Suppression
1.5
Auto-Negotiation
complete
1=
0=
Auto-Negotiation process completed
Auto-Negotiation process not completed
1.4
Remote Fault
1=
0=
Remote fault condition detected
No remote fault condition detected
1.3
Auto-Negotiation
Ability
1=
0=
PHY is able to perform Auto-Negotiation
PHY is not able to perform Auto-Negotiation
1.2
Link Status
1=
0=
Link is up
Link is down
RO/LL
Note 2
0
1.1
Jabber Detect
1=
0=
Jabber condition detected
Jabber condition not detected
RO/LH
Note 2
0
1.0
Extended
Capability
1=
0=
Extended register capabilities
Basic register set capabilities only
RO
1
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Bits that Latch High (LH) or Latch Low (LL) automatically clear when read.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
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23 August 2011
Table 18
12.0 Register Definitions
PHY Identification Register 1 (Address 2)
Bit
Name
2.15:0
Type1
Description
PHY ID Number
The PHY identifier composed of bits 3 through
18 of the OUI
Default
RO
0013
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
Table 19
PHY Identification Register 2 (Address 3)
Bit
Name
3.15:10
3.9:4
Default
PHY ID number
The PHY identifier composed of bits 19 through
24 of the OUI
RO
011110
Manufacturer’s model
number
6 bits containing manufacturer’s part number
RO
100001
RO
xxxx
(See the
LXT973
Transceiv
er
Transceiv
er
Specificati
on
Update)
Manufacturer’s
revision number
3.3:0
Type1
Description
4 bits containing manufacturer’s revision
number
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
Figure 28
PHY Identifier Bit Mapping
a
Organizationally Unique Identifier
b c
r s
x
PHY ID Register #2 (Address 3)
PHY ID Register #1 (address 2) = 0013
15
0 15
10 9
4
3
0
0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 1 0 1 1 1 1 0 X X X X X X X X X X
00
20
7B
5
0
3
0
The Cortina OUI is 00207B hex
Manufacturer’s
Model Number
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Revision
Number
Page 68
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 20
12.0 Register Definitions
Auto-Negotiation Advertisement Register (Address 4)
Bit
Name
Description
Type1
Default
4.15
Next Page
1 = PHY is capable of Next Page exchanges
0 = PHY is not capable of Next Page exchanges
R/W
0
4.14
Reserved
Write as 0, ignore on read
RO
0
4.13
Remote Fault
1 = Remote fault.
0 = No remote fault.
R/W
0
4.12
Reserved
Write as 0, ignore on read
R/W
0
4.11
Asymmetric Pause
Pause operation defined in Clause 40 and 27
R/W
0
4.10
Pause
Pause operation defined per IEEE 802.3x
standard
R/W
0
4.9
100BASE-T4
1 = 100BASE-T4 capability is available.
0 = 100BASE-T4 capability is not available.
(The LXT973 Transceiver does not support
100BASE-T4 but allows this bit to be set to
advertise in the auto-negotiation sequence for
100BASE-T4 operation. An external
100BASE-T4 transceiver may be switched in, if
this capability is desired.)
R/W
0
4.8
100BASE-TX
Full-Duplex
1 = DTE is 100BASE-TX full-duplex capable.
0 = DTE is not 100BASE-TX full-duplex
capable.
R/W
0
Note 2
4.7
100BASE-TX
1 = DTE is 100BASE-TX capable.
0 = DTE is not 100BASE-TX capable.
R/W
0
Note 2
4.6
10BASE-T
Full-Duplex
1 = DTE is 10BASE-T full-duplex capable.
0 = DTE is not 10BASE-T full-duplex capable.
R/W
0
Note 2
4.5
10BASE-T
1 = DTE is 10BASE-T capable.
0 = DTE is not 10BASE-T capable.
R/W
0
Note 2
Selector Field,
S
= IEEE 802.3
= IEEE 802.9 ISLAN-16T
= Reserved for future auto-negotiation
development
= Reserved for future auto-negotiation
development
Unspecified or reserved combinations should
not be transmitted.
Note: The selector field can be programmed to
any value. In order for auto-negotiation to
complete, the link partner’s received selector
field must match the value programmed in this
register.
R/W
00001
4.4:0
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Register bits 4.10 and 4.8:5 are initialized based on the pin configuration value.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
249426, Revision 7.0
23 August 2011
Table 21
12.0 Register Definitions
Auto-Negotiation Link Partner Base Page Ability Register (Address 5)
Type1
Default
Next Page
1 = Link Partner has ability to send multiple
pages.
0 = Link Partner has no ability to send multiple
pages.
RO
0
5.14
Acknowledge
1 = Link Partner has received Link Code Word
from LXT973 Transceiver.
0 = Link Partner has not received Link Code
Word from LXT973 Transceiver.
RO
0
5.13
Remote Fault
1 = Remote fault.
0 = No remote fault.
RO
0
5.12
Reserved
Write as 0, ignore on read.
RO
0
Asymmetric Pause
Pause operation defined in IEEE 802.3, Clauses
40 and 27
RO
0
5.10
Pause
Pause operation defined as of IEEE 802.3x
RO
0
5.9
100BASE-T4
1 = Link Partner is 100BASE-T4 capable.
0 = Link Partner is not 100BASE-T4 capable.
RO
0
5.8
100BASE-TX
Full-Duplex
1 = Link Partner is 100BASE-TX full-duplex
capable.
0 = Link Partner is not 100BASE-TX full-duplex
capable.
RO
0
5.7
100BASE-TX
1 = Link Partner is 100BASE-TX capable.
0 = Link Partner is not 100BASE-TX capable.
RO
0
5.6
10BASE-T
Full-Duplex
1 = Link Partner is 10BASE-T full-duplex
capable.
0 = Link Partner is not 10BASE-T full-duplex
capable.
RO
0
5.5
10BASE-T
1 = Link Partner is 10BASE-T capable.
0 = Link Partner is not 10BASE-T capable.
RO
0
Selector Field
S[4:0]
= IEEE 802.3
= IEEE 802.9 ISLAN-16T
= Reserved for future auto-negotiation
development
= Reserved for future auto-negotiation
development
Unspecified or reserved combinations shall not
be transmitted.
RO
00000
Bit
5.15
5.12:11
5.4:0
Name
Description
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
Note: Per IEEE revised standard November 1997, this register is no longer used to store Link Partner Next
Pages. Register 8 is now used for this purpose.
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Datasheet
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23 August 2011
Table 22
12.0 Register Definitions
Auto-Negotiation Expansion Register (Address 6)
Bit
6.15:6
Name
Description
Type1
Default
Reserved
Write as 0, ignore on read
RO
0
6.5
Base Page
This bit indicates the status of the
auto-negotiation variable, Base Page. It also
flags synchronization with the auto-negotiation
state diagram, allowing detection of interrupted
links. This bit is only used if Register bit 16.1
(Alternate Next Page feature) is set.
1 = base_page = true
0 = base_page = false
RO/LH
Note 2
0
6.4
Parallel Detection
Fault
1 = Parallel Detection Fault has occurred.
0 = Parallel Detection Fault has not occurred.
RO/LH
Note 2
0
6.3
Link Partner Next
Page Able
1 = Link partner is Next Page able.
0 = Link partner is not Next Page able.
RO
0
6.2
Next Page Able
1 = Local device is Next Page able
0 = Local device is not Next Page able
RO
1
6.1
Page Received
Indicates that a new page has been received
and the received code word has been loaded
into Register 5 (Base Pages) or Register 8 (Next
Pages) as specified in clause 28 of IEEE 802.3.
This bit is cleared on read. If Register bit 16.1 is
set, the Page Received bit is also cleared when
mr_page_rx = false, or transmit_disable = true.
RO/LH
Note 2
0
6.0
Link Partner AutoNeg Able
1 = Link partner is auto-negotiation able.
0 = Link partner is not auto-negotiation able.
RO
0
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Bits that Latch High (LH) or Latch Low (LL) automatically clear when read.
Note: This table contains modifications that are selectable in Cortina PHYs. These modifications are used
to ease the implementation of software Next Page. See separate Cortina tutorial/white-paper on the
usage of Next Pages.
Table 23
Auto-Negotiation Next Page Transmit Register (Address 7)
Bit
Name
Description
Type1
Default
7.15
Next Page
(NP)
1 = Additional Next Pages follow
0 = Last page
R/W
0
7.14
Reserved
Write as 0, ignore on read
RO
0
7.13
Message Page
(MP)
1 = Message Page
0 = Unformatted page
R/W
1
7.12
Acknowledge 2
(ACK2)
1 = Complies with message
0 = Does not comply with message
R/W
0
7.11
Toggle
(T)
1 = Previous value of the transmitted Link Code
Word was equal to logic zero
0 = Previous value of the transmitted Link Code
Word was equal to logic one
R/W
0
7.10:0
Message/Unformatted
Code Field
See Appendix C of the IEEE 802.3 standards for
Next Page descriptions
R/W
00000000
001
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
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Datasheet
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23 August 2011
Table 24
12.0 Register Definitions
Auto-Negotiation Link Partner Next Page Ability Register (Address 8)
Description
Type1
Default
8.15
Next Page
(NP)
1 = Link Partner has additional Next Pages to
send
0 = Link Partner has no additional Next Pages to
send
RO
0
8.14
Acknowledge
(ACK)
1 = Link Partner has received Link Code Word
from LXT973 Transceiver
0 = Link Partner has not received Link Code
Word from LXT973 Transceiver
RO
0
8.13
Message Page
(MP)
1 = Page sent by the Link Partner is a Message
Page
0 = Page sent by the Link Partner is an
Unformatted Page
RO
0
8.12
Acknowledge 2
(ACK2)
1 = Link Partner complies with the message
0 = Link Partner cannot comply with the
message
RO
0
8.11
Toggle
(T)
1 = Previous value of the transmitted Link Code
Word was equal to logic zero
0 = Previous value of the transmitted Link Code
Word equalled logic one
RO
0
Message/Unformatted
Code Field
See Appendix C of the IEEE 802.3 standards for
Next Page descriptions
RO
00000000
000
Type1
Default
Bit
8.10:0
Name
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
Table 25
Port Configuration Register (Address 16) (Sheet 1 of 2)
Bit
Name
Description
16.15
Reserved
Write as 0, ignore on read
R/W
0
16.14
Link Test Disable
1 = Force Link pass (sets appropriate registers
and LEDs to pass)
0 = Normal operation
R/W
0
16.13
Transmit Disable
1 = Disable twisted-pair transmitter
0 = Normal operation
R/W
0
16.12
Bypass Scramble
(100BASE-TX)
1 = Bypass Scrambler and De-scrambler
0 = Normal operation
R/W
0
16.11
Bypass 4B/5B
(100BASE-TX)
1 = Bypass 4B/5B encoder and decoder
0 = Normal Operation
R/W
0
16.10
Jabber
(10BASE-T)
1 = Disable Jabber
0 = Normal operation
R/W
0
16.9
SQE
(10BASE-T)
1 = Enable Heart Beat
0 = Disable Heart Beat
R/W
0
16.8
TP Loopback
(10BASE-T)
1 = Disable twisted-pair loopback during halfduplex operation
0 = Normal Operation - loopback in 10BASE-T,
half-duplex
R/W
0
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Register bit 16.0 is latched in from FIBER_TPn on hardware reset.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
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23 August 2011
Table 25
12.0 Register Definitions
Port Configuration Register (Address 16) (Sheet 2 of 2)
Bit
Name
Description
Type1
Default
16.7
CRS Select
(10BASE-T)
1 = CRS de-assert extends to RXDV de-assert
0 = Normal operation
R/W
1
16.6
Reserved
Write as 0, ignore on read
R/W
0
16.5
PRE_EN
Preamble Enable.
0 = Set RXDV High coincident with SFD
1 = Set RXDV High and RXD = preamble when
CRS is asserted.
R/W
0
16.4
Reserved
Write as 0, ignore on read
R/W
0
16.3
10M Serial
1 = 10BASE_T serial mode. 10 Mbps data is
driven serially on RXD in this mode.
0 = Utilize normal MII mode-nibble.
R/W
0
16.2
Far End Fault
Transmission Enable
1 = Enable Far End Fault transmission.
0 = Disable Far End Fault transmission.
R/W
1
16.1
Alternate NP Feature
1 = Enable Alternate auto-negotiation Next
Page feature.
0 = Disable Alternate auto-negotiation Next
Page feature.
R/W
0
16.0
Fiber Select
1 = Select fiber mode for this port.
0 = Select twisted-pair mode for this port.
R/W
LHR
Note 2
Type1
Default
RO
000
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Register bit 16.0 is latched in from FIBER_TPn on hardware reset.
Table 26
Special Function Register (Address 27) (Sheet 1 of 2)
Bit
Name
Description
Line Length Indication
27.15:13
Line Length
Indicator
111 = Longest
110 =
101 =
100 =
011 =
010 =
001 =
000 = Shortest
Approximate
line-length
corresponding to
each value will be
determined at
design verification
(Not valid when
agcset (Register
bit 30.13 = 1)
Special Functions
27.12
27.11:10
27.9
Reserved
Write as 0, ignore on read
R/W
0
Per-Port Rise
time Control
00 = 3.3 ns (default pins TxSLEW)
01 = 3.6 ns
10 = 3.9 ns
11 = 4.2 ns
R/W
LHR
Note 2
Auto MDIX enable
0 = Disable Auto-MDIX
1 = Enable Auto-MDIX
R/W
1
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Register bits 27.11:10 are latched in from hardware pins on hardware reset.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
249426, Revision 7.0
23 August 2011
Table 26
12.0 Register Definitions
Special Function Register (Address 27) (Sheet 2 of 2)
Bit
Name
Description
Type1
Default
27.8
Auto MDIX
MDI/MDIX selection
0 = MDI, transmit on pair A and receive on pair B
1 = MDIX, transmit on pair B and receive on pair A
R/W
1
27.7
Analog Loopback
1 = Enable Analog Loopback (transmits on
twisted-pair)
0 = Disable Analog Loopback
R/W
0
27.6
Loopback Detect
Enable
1 = Enable automatic loopback detection.
0 = Disable automatic loopback detection
R/W
0
27.5
Loopback SpeedUp Enable
1 = Enable automatic loopback detection speed-up
0 = Disable automatic loopback detection speed-up
R/W
0
27.4
Loopback
Detected
1 = Loopback detected
0 = No loopback detected
RO
0
27.3:0
Reserved
Write as 0, ignore on read
R/W
00
1. Refer to Table 15 on page 65 for Register Bit Descriptions.
2. Register bits 27.11:10 are latched in from hardware pins on hardware reset.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
249426, Revision 7.0
23 August 2011
13.0
13.0 Magnetics Information
Magnetics Information
The LXT973 Transceiver requires a 1:1 ratio for both the receive and transmit path. Refer to
Table 30 for transformer requirements. Transformers meeting these requirements are
available from various manufacturers. Designers should test and validate all magnetics
before using them in production.
Table 27
Magnetics Requirements
Parameter
Min
Nom
Max
Units
Test Condition
–
1:1, 1:1
–
–
–
Insertion Loss
0.0
–
0.6
dB
–
Primary Inductance
350
–
–
H
–
Transformer Isolation
2
–
–
kV
–
Differential to common mode
rejection
40
–
–
dB
.1 to 60 MHz
35
–
–
dB
60 to 100 MHz
17
–
–
dB
.1 to 60 MHz
15
–
–
dB
60 to 100 MHz
2.0
–
3.5
ns
10% to 90%
Turns Ratio
Return Loss
Rise Time
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Datasheet
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23 August 2011
14.0 Test Specifications
14.0
Test Specifications
Note:
Table 28 on page 76 through Table 51 on page 91 and Figure 29 on page 81 through
Figure 42 on page 90 represent the performance specifications of the LXT973 Transceiver.
These specifications are guaranteed by test except where noted “by design.” Minimum and
maximum values listed in Table 30 on page 77 through Table 51 on page 91 apply over the
recommended operating conditions specified in Table 29.
Table 28
Absolute Maximum Ratings
Parameter
Min
Max
Units
VCCA, Vcc3
-0.3
3.0
V
Supply Voltage
VCCPECL,
VCCIO3
-0.3
4.0
V
Storage Temperature
TST
-65
+150
ºC
1,2
Caution:
Sym
Exceeding these values may cause permanent damage.
Functional operation under these conditions is not implied.
Exposure to maximum rating conditions for extended periods may affect
device reliability.
1. The voltage setting for VCCIO must be equal to or greater than the voltage setting for VCC core.
2. VCCIO and VCC core must be run at the same voltage extremes (for example, do not run VCCIO at
maximum voltage and VCC core at minimum voltage.
3. VCCA = VCCR plus VCCT
VCC = VCCD (Digital Core)
VCCIO = Digital I/O Ring
VCCPECL = PECL supply for fiber
Table 29
Operating Conditions (Sheet 1 of 2)
Sym
Min
Typ1
Max
Units
Commercial Operating Temperature
TA
0
–
+70
ºC
Extended Operating Temperature
TA
+85
ºC
Parameter
Analog & Digital
Recommended
Supply Voltage2
2.38
2.5
2.63
V
I/O @ 3.3 V
3
VCCIO
3.14
3.3
3.45
V
I/O @ 2.5 V
VCCIO3
2.38
2.5
2.63
V
3
3.14
3.3
3.45
V
3
VCCPECL
2.38
2.5
2.63
V
100BASE-TX
ICC
–
–
150
mA
10BASE-T
ICC
–
–
80
mA
I/O @ 3.3 V
I/O @ 2.5 V
Vcc Current
-40
3
VCCA, Vcc
VCCPECL
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Voltages are with respect to ground unless otherwise specified.
3. VCCA = VCCR plus VCCT
VCC = VCCD (digital core)
VCCIO = digital I/O ring
VCCPECL = PECL supply for fiber
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
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23 August 2011
Table 29
14.0 Test Specifications
Operating Conditions (Sheet 2 of 2)
Parameter
VCC Current
Sym
Min
Typ1
Max
Units
100BASE-FX
ICC
105
mA
Power-Down Mode
ICC
–
–
12
mA
Auto-Negotiation
ICC
–
–
85
mA
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Voltages are with respect to ground unless otherwise specified.
3. VCCA = VCCR plus VCCT
VCC = VCCD (digital core)
VCCIO = digital I/O ring
VCCPECL = PECL supply for fiber
Table 30
Digital Input/Output Characteristics2
Parameter
Max
Units
Test
Conditions
0.8
V
–
Min
Input Low voltage
VIL
–
Input High voltage
VIH
2.0
–
–
V
–
II
-10
–
10
A
0.0 < VI < VCC
Output Low voltage
VOL
–
–
0.4
V
IOL = 4 mA
Output High voltage
VOH
2.4
–
–
V
IOH = -4 mA
Input Current
Typ
1
Symbol
–
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Applies to all pins except SD, MII, REFCLK, and LED pins. Refer to Table 32 for MII I/0 Characteristics.
Table 31
Digital Input/Output Characteristics - SD Pins
Parameter
Symbol
Min
Typ
1
Max
Units
Test
Conditions
2.5 V Operation2
Input Low Voltage
Vil
0.69
0.8
1.03
V
VCCPECL =
2.5 V
Input High Voltage
Vih
1.34
1.6
1.62
V
VCCPECL =
2.5 V
3.3 V Operation3
Input Low Voltage
Vil
1.49
1.6
1.83
V
VCCPECL =
3.3 V
Input High Voltage
Vih
2.14
2.4
2.42
V
VCCPECL =
3.3 V
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. For 2.5 V operation, SD_2P5V = VCCPECL and VCCPECL=2.5 V.
3. For 3.3 V operation, SD_2P5V = GNDPECL or Floating and VCCPECL=3.3 V.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
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Datasheet
249426, Revision 7.0
23 August 2011
Table 32
14.0 Test Specifications
Digital Input/Output Characteristics - MII Pins
Parameter
Max
Units
Test
Conditions
–
0.8
V
–
2.0
–
–
V
–
Symbol
Min
Input Low voltage
VIL
–
Input High voltage
VIH
Input Current
Output Low voltage
Typ
1
II
-10
–
10
A
0.0 < VI < VCC
VOL
–
–
0.4
V
IOL = 4 mA
VOH
2.4
–
–
V
IOH = -4 mA,
VCCIO = 3.3 V
VOH
2.0
–
–
V
IOH = -4 mA,
VCCIO = 2.5 V
Output High voltage
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Parameter is guaranteed by design and not subject to production testing.
Table 33
REFCLK Characteristics
Parameter
Symbol
Min
Typ
1
Max
Units
Test
Conditions
Input Low voltage
VIL
–
–
0.8
V
–
Input High voltage
VIH
2.0
–
–
V
–
Input Clock Frequency
Tolerance2
f
–
–
+50
ppm
–
Input Clock Duty Cycle2
Tdc
40
–
60
%
–
CIN
–
3.0
–
pF
–
2
Input Capacitance
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Parameter is guaranteed by design: not subject to production testing.
Table 34
LED Pin Characteristics
Symbol
Min
Typ1
Max
Units
Test
Conditions
Output Low Voltage
VOL
–
–
0.4
V
IOL = 10 mA
Output High Current
IOH
–
–
10
A
VOH = VCC max
II
-10
–
10
A
0 < VI < VCCIO
Parameter
Input Leakage Current
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 78
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 35
14.0 Test Specifications
100BASE-TX Transceiver Characteristics
Parameter
Max
Units
Test
Conditions
1.0
1.05
V
Note 2
100
102
%
Note 2
Sym
Min
Typ
Peak differential output voltage
VP
0.95
Signal amplitude symmetry
Vss
98
1
Signal rise/fall time
TRF
3.0
3.5
5.0
ns
Note 2
Rise/fall time symmetry
TRFS
–
.25
0.5
ns
Note 2
Duty cycle distortion
DCD
35
50
65
%
Offset from
16 ns pulse
width at 50% of
pulse peak
Overshoot/Undershoot
VOS
–
–
5
%
–
–
–
0.75
1.4
ns
–
Jitter (measured differentially)
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Measured at the line side of the transformer, line replaced by 100(+/-1%) resistor.
Table 36
10BASE-T Transceiver Characteristics
Parameter
Sym
Min
Typ
1
Max
Units
Test
Conditions
Transmitter
Peak differential output voltage
VOP
2.2
2.5
2.8
V
Note 2
Jitter magnitude added by the
MAU and PLS sections 3, 4
ttx-jit
–
3.2
11
ns
–
500
585
mV
Peak
5 MHz square
wave input
Receiver
Differential squelch threshold
VDS
300
1. Typical values are at 25°C and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Parameter is guaranteed by design; not subject to production testing.
3. IEEE 802.3 specifies maximum jitter addition at 1.5 ns for the AUI cable, 0.5 ns from the encoder, and
3.5 ns from the MAU.
4. After line model specified by IEEE 802.3 for 10BASE-T MAU.
Table 37
100BASE-FX Transceiver Characteristics (Sheet 1 of 2)
Parameter
Sym
Min
Typ
1
Max
Units
Test
Conditions
Transmitter
Peak-to-peak differential output
voltage
Vdiffp-p
0.6
1.3
1.5
V
–
Signal rise/fall time
Trf
–
1.2
1.9
ns
20% 80 %
2.0 pF load
Jitter (measured differentially)
–
–
0.5
1.4
ns
–
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 79
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 37
14.0 Test Specifications
100BASE-FX Transceiver Characteristics (Sheet 2 of 2)
Parameter
Sym
Min
VIP
0.55
VCMIR
–
Max
Units
Test
Conditions
–
1.5
V
–
–
VCC 0.7
V
–
Typ
1
Receiver
Peak differential input voltage
Common mode input range
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Table 38
10BASE-T Link Integrity Timing Characteristics
Parameter
Max
Units
Test
Conditions
–
150
ms
–
2
–
7
Link
Pulses
–
Sym
Min
Time Link Loss Receive
TLL
50
Link Detection
TLP
Typ
1
Link Min Receive Timer
TLR MIN
2
–
7
ms
–
Link Max Receive Timer
TLR MAX
50
–
150
ms
–
Tlt
8
–
24
ms
–
Tlpw
60
114
150
ns
–
Link Transmit Period
Link Pulse Width
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Table 39
Twisted-Pair Pins
Parameter
Sym
Min
Receive input impedance2
ZIN
–
Driver output impedance2
(Line driver output enabled)
RO
–
Max
Units
Test
Conditions
100
–
Between RX+
and RX-
100
–
Between TX+
and TX-
Typ
1
1. Typical values are at 25°C and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. Parameter is guaranteed by design; not subject to production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 80
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
15.0
15.0 Timing Diagrams
Timing Diagrams
The LXT973 Transceiver device meets all timings for MII per the IEEE 802.3u standard.
Figure 29 through Figure 34 on page 86 refer to MII timings.
Figure 29
100BASE-TX Transmit Timing - 4B Mode
0ns
250ns
t1
TXCLK
TXEN
t2
TXD
t5
Twisted-Pair
Output
t4
t3
CRS
Note:
Table 40
Twisted-pair output default pins are as follows: DIFAP/N_0 and
DIFAP/N_1.
MII - 100BASE-TX Transmit Timing Parameters - 4B Mode
Max
Units
Test
Conditions
–
–
ns
–
0
–
–
ns
–
t3
2
4
5
BT
–
t4
2
4
5
BT
–
t5
–
5
–
BT
–
Parameter
Sym
Min
TXD, TXEN, TXER setup to
TXCLK High
t1
12
TXD, TXEN, TXER hold
from TXCLK High
t2
TXEN sampled to CRS asserted
TXEN sampled to CRS
de-asserted
TXEN sampled to twisted-pair
output (Tx latency)
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 81
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 30
15.0 Timing Diagrams
100BASE-TX Receive Timing - 4B Mode
0ns
250ns
Twisted-Pair
Input
t4
t5
CRS
t3
RXDV
t1
t2
RXD
RXCLK
t6
t7
COL
Note:
Table 41
Twisted-pair input default pins are as follows: DIFBP/N_0 and
DIFBP/N_1.
MII - 100BASE-TX Receive Timing Parameters - 4B Mode
Max
Units
Test
Conditions
–
–
ns
–
10
–
–
ns
–
t3
3
4
5
BT
–
Receive start of
“J” to CRS asserted
t4
11
–
16
BT
–
Receive start of “T” to CRS
de-asserted
t5
10
14
17
BT
–
Receive start of “J” to COL
asserted
t6
10
–
15
BT
–
Receive start of “T” to COL
de-asserted
t7
14
17
20
BT
–
Parameter
Sym
Min
RXD, RXDV, RXER setup
to RXCLK High
t1
10
RXD, RXDV, RXER hold
from RXCLK High
t2
CRS asserted to RXD,
RXDV
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 82
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 31
15.0 Timing Diagrams
100BASE-FX Transmit Timing
QV
QV
W
7;&/.
7;(1
W
7;'!
W
',)$31
W
W
&56
Table 42
100BASE-FX Transmit Timing Parameters
Max
Units
Test
Conditions
–
–
ns
–
0
–
–
ns
–
t3
2
–
5
BT
–
TXEN sampled to CRS
de-asserted
t4
1
–
5
BT
–
TXEN sampled to fiber output (Tx
latency)
t5
–
4
–
BT
–
Parameter
Sym
Min
TXD, TXEN, TXER setup to
TXCLK High
t1
12
TXD, TXEN, TXER hold
from TXCLK High
t2
TXEN sampled to CRS asserted
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 83
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 32
15.0 Timing Diagrams
100BASE-FX Receive Timing
QV
QV
',)%31
W
W
&56
W
5;'9
W
5;'!
W
5;&/.
W
&2/
Table 43
W
100BASE-FX Receive Timing Parameters
Max
Units
Test
Conditions
–
–
ns
–
10
–
–
ns
–
t3
3
–
5
BT
–
Receive start o “J” to CRS
asserted
t4
9
–
14
BT
–
Receive start of “T” to CRS
de-asserted
t5
13
–
17
BT
–
Receive start of “J” to COL
asserted
t6
10
–
14
BT
–
Receive start of “T” to COL
de-asserted
t7
13
–
18
BT
–
Parameter
Sym
Min
RXD, RXDV, RXER setup
to RXCLK High
t1
10
RXD, RXDV, RXER hold
from RXCLK High
t2
CRS asserted to RXD,
RXDV
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 84
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 33
15.0 Timing Diagrams
10BASE-T Transmit Timing (Parallel Mode)
TXCLK
t1
TXD,
TXEN,
TXER
t2
t3
t4
CRS
t5
Twisted-Pair
Output
Note:
Table 44
Twisted-pair output default pins are as follows: DIFAP/N_0 and DIFAP/N_1.
MII - 10BASE-T Transmit Timing Parameters (Parallel Mode)
Max
Units
Test
Conditions
–
–
ns
–
0
–
–
ns
–
t3
–
5.5
–
BT
–
TXEN sampled to CRS
de-asserted
t4
–
5
–
BT
–
TXEN sampled to twisted-pair
output (Tx latency)
t5
–
575
–
ns
–
Parameter
Sym
Min
TXD, TXEN, TXER setup to
TXCLK High
t1
10
TXD, TXEN, TXER hold from
TXCLK High
t2
TXEN sampled to CRS asserted
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 85
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 34
15.0 Timing Diagrams
10BASE-T Receive Timing (Parallel Mode)
RXCLK
t1
t3
RXD,
RXDV,
RXER
t2
t5
t4
CRS
t6
t7
Twisted-Pair
Input
t9
COL
Note:
Table 45
t8
Twisted-pair input default pins are as follows: DIFBP/N_0 and DIFBP/N_1.
MII - 10BASE-T Receive Timing Parameters (Parallel Mode)
Max
Units
Test
Conditions
–
–
ns
–
10
–
–
ns
–
t3
–
64
–
BT
–
CRS asserted to RXD, RXDV,
RXER asserted2
t4
–
62
–
BT
–
RXD, RXDV, RXER de-asserted
to CRS de-asserted3
t5
–
0.5
–
BT
–
Twisted-pair input to CRS
asserted
t6
–
4
–
BT
–
Twisted-pair input quiet to CRS
de-asserted
t7
–
4
–
BT
–
Twisted-pair input to COL
asserted
t8
–
4
–
BT
–
Twisted-pair input quiet to COL
de-asserted
t9
–
4
–
BT
–
Parameter
Sym
Min
RXD, RXDV, RXER setup to
RXCLK High
t1
10
RXD, RXDV, RXER hold from
RXCLK High
t2
Twisted-pair input to RXD out (Rx
latency)
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. CRS is asserted. RXD/RXDV are driven at the start of SFD (64 BT) unless Register bit 16.5 is set.
3. If Register bit 16.7 is set, CRS extends to RXDV de-assert.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 86
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 35
15.0 Timing Diagrams
10BASE-T SQE (Heartbeat) Timing
TXCLK
TXEN
t1
t2
COL
Table 46
10BASE-T SQE (Heartbeat) Timing Parameters
Parameter
Max
Units
Test
Conditions
1.2
1.6
s
–
.95
1.5
s
–
Sym
Min
Typ
COL (SQE) delay after TXEN
de-asserted
t1
0.65
COL (SQE) pulse duration
t2
0.5
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Figure 36
10BASE-T Jab and Unjab Timing
TXEN
t1
TXD
t2
COL
Table 47
10BASE-T Jab and Unjab Timing Parameters
Parameter
Sym
Min
Maximum transmit time
t1
20
Unjab time
t2
250
Max
Units
Test
Conditions
–
150
ms
–
–
750
ms
–
Typ
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 87
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 37
15.0 Timing Diagrams
Fast Link Pulse Timing
Clock Pulse
Twisted-Pair
Output
Data Pulse
t1
t1
t2
Note:
Figure 38
Clock Pulse
t3
Twisted-pair output default pins are as follows: DIFAP/N_0 and DIFAP/N_1.
FLP Burst Timing
FLP Burst
FLP Burst
Twisted-Pair
Output
t4
t5
Note:
Table 48
Twisted-pair output default pins are as follows: DIFAP/N_0 and DIFAP/N_1.
Fast Link Pulse Timing Parameters
Max
Units
Test
Conditions
116
118
ns
–
55.5
63
69.5
s
–
t3
111
126
139
s
–
FLP burst width
t4
–
2.0
–
ms
–
FLP burst to FLP burst
t5
8
10
24
ms
–
Clock/Data pulses per burst
–
17
–
33
ea
–
Parameter
Sym
Min
Typ
Clock/Data pulse width
t1
115
Clock pulse to Data pulse
t2
Clock pulse to Clock pulse
1
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 88
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 39
15.0 Timing Diagrams
MDIO Input Timing
MDC
t4
t2
t1
MDIO
Figure 40
MDIO Output Timing
MDC
t3
MDIO
Table 49
MDIO Timing Parameters
Test
Conditions
Sym
Min
Typ1
Max
Units
MDIO setup before MDC
t1
10
–
–
ns
When sourced
by STA
MDIO hold after MDC
t2
10
–
–
ns
When sourced
by STA
MDC to MDIO output delay
t3
10
–
3002
ns
When sourced
by PHY
MDC Clock Speed
t4
–
–
20
MHz
Parameter
–
1. Typical values are at 25°C, and are for design aid only, are not guaranteed, and are not subject to
production testing.
2. When operated at 2.5 MHz.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 89
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 41
15.0 Timing Diagrams
Power-Up Timing
v
t
VCC
MDIO,etc.
Table 50
Power-Up Timing Parameters
Parameter
Voltage threshold
Power-up delay
2
Sym
Min
Typ1
Max
Units
Test
Conditions
v1
2.9
–
–
V
–
t1
–
–
300
s
–
o
1. Typical values are at 25 C and are for design aid only; not guaranteed and not subject to producing
testing.
2. Power-up delay is specified as a maximum value because it refers to the guaranteed performance of the
PHY. The PHY comes out of reset after a delay of no more than 300 S. System designers should
consider this as a minimum value. After threshold V1 is reached, the MAC should delay no less than
300 S before accessing the MDIO port.
Figure 42
RESET Pulse Width and Recovery Timing
RESET
t1
t2
MDIO,etc.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 90
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Table 51
15.0 Timing Diagrams
RESET Pulse Width and Recovery Timing Parameters
Parameter
RESET pulse width
2
RESET recovery delay
Sym
Min
Typ1
Max
Units
Test
Conditions
t1
10
–
–
s
–
t2
–
–
300
s
–
o
1. Typical values are at 25 C and are for design aid only; not guaranteed and not subject to producing
testing.
2. Reset recovery delay is specified as a maximum value because it refers to the PHY’s guaranteed
performance. - the PHY comes out of reset after a delay of no more than 300 S. System designers
should consider this as a minimum value. After de-asserting RESET, the MAC should delay no less than
300 S before accessing the MDIO port.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 91
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
16.0 Mechanical Specifications
16.0
Mechanical Specifications
Figure 43
Mechanical Specifications
100-Pin Plastic Quad Flat Pack
• Part Number: LXT973QC & LXT973QE
• Temperature Range:
— Commercial: 0 to 70C &
— Extended: -40 to +85C.
D
D1
D3
Inches
Millimeters
Dim
E1
E3
E
1
D Side pin count = 30 pins
E Side pin count = 20 pins
e
e/
for sides with even
number of pins
A1
L
B
3
Max
A
–
0.134
–
3.40
0.010
–
0.25
–
A2
0.100
0.120
2.55
3.05
B
0.009
0.015
0.22
0.38
D
0.931
0.951
23.65
24.15
D1
0.783
0.791
19.90
20.10
0.742 REF
18.85 REF
E
0.695
0.715
17.65
18.15
E1
0.547
0.555
13.90
14.10
E3
0.486 REF
12.35 REF
e
0.026 BSC (nominal)
0.65 BSC (nominal)
0.026
L1
A2
Min
A1
L
3
A
Max
D3
2
for sides with odd
number of pins
L1
Min
0.037
0.65
0.077 REF
0.95
1.95 REF
q3
5°
16°
5°
16°
q
0°
7°
0°
7°
BSC: Basic Spacing Between Centers
16.1
Top Label Marking
Figure 45 shows a sample PQFP package for the LXT973 Transceiver.
Notes:
1. In contrast to the Pb-Free (RoHS-compliant) PQFP package, the non-RoHS-compliant
packages do not have the “e3” symbol in the last line of the package label.
2. Further information regarding RoHS and lead-free components can be obtained from
your local Cortina representative.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 92
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 44
16.1 Top Label Marking
Example of Top Marking Information Labeled as Cortina Systems, Inc.
AAAOOOAAA
AywwX00a
Country of Origin
Figure 45
Device Name
FPO Traceability Code
Sample PQFP Package (marked as Intel*) – LXT973QC Transceiver
Pin 1
LXT973QC A3
XXXXXXXX
Part Number
FPO Number
BSMC
FV
Bottom Side Mark Code
B5437-01
Figure 46 shows a sample Pb-free RoHS-compliant PQFP package for the LXT973
Transceiver.
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 93
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 46
16.1 Top Label Marking
Sample Pb-Free (RoHS-Compliant) PQFP Package (marked as Intel*) –
Intel* EGLX973QC Transceiver
Pin 1
EGLXT973C A3
Part Number
XXXXXXXX
FPO Number
BSMC
e3
Pb-Free Indication
FV
Bottom Side Mark Code
B5438-01
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 94
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
17.0
17.0 Product Ordering Information
Product Ordering Information
Table 52 lists the LXT973 Transceiver product ordering information. Figure 47 provides the
ordering information matrix.
Table 52
Product Ordering Information
Number
Revision
Package Type
Pin Count
RoHS Compliant
SLXT973QC.A3V
A3
PQFP
100
No
EGLXT973QC.A3V
A3
PQFP
100
Yes
SLXT973QE.A3V
A3
PQFP
100
No
EGLXT973QE.A3V
A3
PQFP
100
Yes
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 95
LXT973 Transceiver
Datasheet
249426, Revision 7.0
23 August 2011
Figure 47
17.0 Product Ordering Information
Ordering Information – Sample
S
LXT
973
QP
C
A3
Product Revision
xn = 2 Alphanumeric characters
Temperature Range
A = Ambient (0 – 550 C)
C = Commercial (0 – 700 C)
E = Extended (-40 – 850 C)
Internal Package Designator
L = LQFP
P = PLCC
N = DIP
Q = PQFP
H = QFP
T = TQFP
B = BGA
C = CBGA
E = TBGA
K = HSBGA (BGA with heat slug
Product Code
xxxxx = 3-5 Digit alphanumeric
IXA Product Prefix
LXT = PHY layer device
IXE = Switching engine
IXF = Formatting device (MAC/Framer)
IXP = Network processor
Intel Package Designator
Pb-Free
Package
Leaded
WB
WJ
HQFP
LQFP
HB
DJ
BJ
TQFP
FA
JA
TQFP
FA
WD
PQFP
HD
QU
PQFP
KU
EG
PQFP
S
WG
QFN
HG
UB
QFN
LB
UC
PDIP
PD
EP
SSOP
PA
EE
PLCC
N
RU
MMAP
HZ
PC
MMAP
RC
EL
PBGA
FL
PR
PBGA
FW
LU
PBGA
GD
EW
PBGA
GW
WF
CBGA
HF
JP
FCBGA
HL
SC
TBGA
TL
B5436-01
Cortina Systems® LXT973 10/100 Mbps Dual-Port Fast Ethernet PHY Transceiver
Page 96
TM
For additional product and ordering information:
www.cortina-systems.com
~ End of Document ~