DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
DS32EL0421 , DS32ELX0421 125 - 312.5 MHz FPGA-Link Serializer with DDR LVDS
Parallel Interface
Check for Samples: DS32EL0421, DS32ELX0421
FEATURES
DESCRIPTION
•
•
•
•
•
•
The DS32EL0421/DS32ELX0421 is a 125 MHz to
312.5 MHz (DDR) serializer for high-speed serial
transmission over FR-4 printed circuit board
backplanes, balanced cables, and optical fiber. This
easy-to-use chipset integrates advanced signal and
clock conditioning functions, with an FPGA friendly
interface.
1
2
•
•
•
•
•
•
•
•
•
•
•
5-bit DDR LVDS Parallel Data Interface
Programmable Transmit De-emphasis
Configurable Output Levels (VOD)
Selectable DC-balanced Encoder
Selectable Data Scrambler
Remote Sense for Automatic Detection and
Negotiation of Link Status
On Chip LC VCOs
Redundant Serial Output (ELX device only)
Data Valid Signaling to Assist with
Synchronization of Multiple Receivers
Supports AC- and DC-coupled Signaling
Integrated CML and LVDS Terminations
Configurable PLL Loop Bandwidth
Programmable Output Termination (50Ω or
75Ω).
Built-in Test Pattern Generator
Loss of Lock and Error Reporting
Configurable via SMBus
48-pin WQFN Package with Exposed DAP
The DS32EL0421/DS32ELX0421 serializes up to 5
parallel input LVDS channels to create a maximum
data payload of 3.125 Gbps. If the integrated DCbalance encoding is enabled, the maximum data
payload achievable is 2.5 Gbps.
The DS32EL0421/DS32ELX0421 serializers feature
remote sense capability to automatically detect and
negotiate
link
status
with
its
companion
DS32EL0124/DS32ELX0124 deserializers without
requiring an additional feedback path.
The parallel LVDS interface reduces FPGA I/O pins,
board trace count and alleviates EMI issues, when
compared to traditional single-ended wide bus
interfaces.
The DS32EL0421/DS32ELX0421 is programmable
through a SMBus interface as well as through control
pins.
TARGET APPLICATIONS
•
•
•
•
•
•
Imaging: Industrial, Medical Security, Printers
Displays: LED Walls, Commercial
Video Transport
Communication Systems
Test and Measurement
Industrial Bus
KEY SPECIFICATIONS
•
•
•
•
•
1.25 to 3.125 Gbps Serial Data Rate
125 to 312.5 MHz DDR Parallel Clock
-40° to +85°C Temperature Range
>8 kV ESD (HBM) Protection
Low Intrinsic Jitter — 35ps at 3.125 Gbps
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2008–2013, Texas Instruments Incorporated
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
Typical Application
DS32ELX0421
5 LVDS
R0
D1
R1
Redundant
Driver
Redundant Link
Retimed
Output
LVDS Interface
D0
Serial to Parallel
Parallel to Serial
Encoder
LVDS
Interface
LVDS
Interface
LVDS
Interface
LVDS
Interface
3.125 Gbps Data Payload
RT0
LVDS
System Logic
5 LVDS
System Logic
FPGA
DS32ELX0124
LVDS Interface
FPGA
LVDS
PLL
Clock
Control
PLL
Control
Clock
Control
Control
SMBus
SMBus
VDD33
1
N/C
2
TXIN4-
TXIN4+
TXIN3-
TXIN3+
TXIN2-
TXIN2+
TXIN1-
TXIN1+
TXIN0-
TXIN0+
TXCLKIN-
TXCLKIN+
48
47
46
45
44
43
42
41
40
39
38
37
Connection Diagram
36
VDD33
35
VDD25
49 DAP = GND
GPIO0
3
34
SMB_CS
GPIO1
4
33
SCK
DC_B
5
32
SDA
RS
6
31
LOCK
30
RESET
DS32EL0421
23
24
N/C
VDD25
N/C
25
22
12
N/C
N/C
21
LF_REF
N/C
26
20
11
N/C
GPIO2
19
LF_CP
N/C
27
18
10
VDD25
DE_EMPH1
17
VDDPLL
TXOUT0-
28
16
9
TXOUT0+
DE_EMPH0
15
RSVD
VDD25
29
14
8
VOD_CTRL
N/C
13
7
N/C
VDD25
See Package Number RHS0048A
TOP VIEW
2
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
VDD33
1
N/C
2
TXIN4-
TXIN4+
TXIN3-
TXIN3+
TXIN2-
TXIN2+
TXIN1-
TXIN1+
TXIN0-
TXIN0+
TXCLKIN-
TXCLKIN+
47
46
45
44
43
42
41
40
39
38
37
SNLS282F – MAY 2008 – REVISED APRIL 2013
48
www.ti.com
36
VDD33
35
VDD25
49 DAP = GND
GPIO0
3
34
SMB_CS
GPIO1
4
33
SCK
DC_B
5
32
SDA
RS
6
31
LOCK
30
RESET
DS32ELX0421
23
24
N/C
VDD25
N/C
25
22
12
N/C
TXOUT1_EN
21
LF_REF
N/C
26
20
11
TXOUT1-
GPIO2
19
LF_CP
TXOUT1+
27
18
10
VDD25
DE_EMPH1
17
VDDPLL
TXOUT0-
28
16
9
TXOUT0+
DE_EMPH0
15
RSVD
VDD25
29
14
8
VOD_CTRL
N/C
13
7
N/C
VDD25
See Package Number RHS0048A
TOP VIEW
PIN DESCRIPTIONS
Pin Name
Pin Number
I/O, Type
Description
Power, Ground and Analog Reference
VDD33
VDD25
I, VDD
3.3V supply
7, 15, 18, 25, I, VDD
35
1, 36
2.5V supply
VDDPLL
28
I, VDD
3.3V supply
VOD_CTRL
14
Analog
VOD control. The serializer output amplitude can be adjusted by connecting this pin to a pulldown resistor. The value of the resistor determines the VOD. See CML LAUNCH AMPLITUDE
for more details.
LF_CP
27
Analog
Loop filter connection for PLL
LF_REF
26
Analog
Loop filter ground reference
Exposed Pad
49
GND
Exposed Pad must be connected to GND by 9 vias
TxOUT0+
TxOUT0-
16
17
O, CML
Inverting and non-inverting high speed CML differential outputs of the serializer. These outputs
are internally terminated.
TxOUT1+
TxOUT1-
19
20
O, CML
DS32ELX0421 ONLY. Redundancy output. Inverting and non-inverting high speed CML
differential outputs of the serializer. These outputs are internally terminated
CML I/O
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
3
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
PIN DESCRIPTIONS (continued)
Pin Name
Pin Number
I/O, Type
Description
37
38
I, LVDS
Serializer input clock. TxCLKIN+/- are the inverting and non-inverting LVDS transmit clock input
pins.
39, 40,
41, 42,
43, 44,
45, 46,
47, 48
I, LVDS
Serializer input data. TxIN[4:0]+/- are the inverting and non-inverting LVDS serializer input data
pins.
LVDS Parallel Data Bus
TxCLKIN+
TxCLKINTxIN[4:0]+/-
LVCMOS Control Pins
DC_B
RS
5
6
I,
LVCMOS
DC-balance and Remote Sense pins. See Device Configuration section DEVICE
CONFIGURATION for device behavior.
DE_EMPH0
DE_EMPH1
9
10
I,
LVCMOS
DE_EMPH0, DE_EMPH1 select the output de-emphasis level. These pins are internally pulldown.
00: Off
01: Low
10: Medium
11: Maximum
TXOUT1_EN
12
I,
LVCMOS
DS32ELX0421 ONLY. When held high, redundant output TxOUT1+/- is enabled. This pin must
be tied high when using TxOUT1+/-.
RESET
30
I,
LVCMOS
When held low, reset the device.
0 = Device Reset
1 = Normal operation
LOCK
31
O,
LVCMOS
Lock indication output. The input data on TxIN[0:4]+/- pins is ignored when LOCK pin is high.
SCK
33
I/O,
SMBus
SMBus compatible clock.
SDA
32
I/O,
SMBus
SMBus compatible data line.
SMB_CS
34
I, SMBus
SMBus chip select. When held high, SMBus management control is enabled.
GPIO0
3
I/O,
LVCMOS
Software configurable I/O pin.
GPIO1
4
I/O,
LVCMOS
Software configurable I/O pin.
GPIO2
11
I/O,
LVCMOS
Software configurable I/O pin.
2, 8, 12, 13,
19, 20, 21,
22, 23, 24,
29
Misc.
No Connect, for DS32EL0421
2, 8, 13, 21,
22, 23, 24,
29
Misc.
No Connect, for DS32ELX0421
SMBus Interface
Other
NC
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
4
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Absolute Maximum Ratings
(1) (2)
−0.3V to +4V
Supply Voltage (3.3V VDD33)
−0.3V to +3V
Supply Voltage (2.5V VDD25)
LVCMOS Input Voltage
−0.3V to (VDD + 0.3V)
LVCMOS Output Voltage
−0.3V to (VDD + 0.3V)
LVDS Input Voltage (IN+, IN-)
−0.3V to +3.6V
CML Output Voltage
−0.3V to +3.6V
Junction Temperature
+125°C
Storage Temperature Range
-65°C to +150°C
Lead Temperature Range
Soldering (4 sec.)
+260°C
Thermal Resistance, θJA
25°C/W
ESD Susceptibility
HBM
(1)
(2)
(3)
(3)
>8 kV
“Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of
device reliability and/or performance. Functional operation of the device and/or non-degradation at the Absolute Maximum Ratings or
other conditions beyond those indicated in the Recommended Operating Conditions is not implied. The Recommended Operating
Conditions indicate conditions at which the device is functional and the device should not be operated beyond such conditions.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/Distributors for availability and specifications.
Human Body Model, applicable std. JESD22-A114C
Recommended Operating Conditions
Min
Typ
Max
Units
Supply Voltage (VDD33 – GND)
3.135
3.3
3.465
V
Supply Voltage (VDD25 – GND)
2.375
2.5
2.625
V
100
mVP-P
-40
+25
+85
°C
Supply Noise Amplitude from 10 Hz to 50 MHz
Ambient Temperature (TA)
Power Supply Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
IDD25
Parameter
Condition
2.5V supply current
1 Output Enabled
2.5V supply current
2 Outputs Enabled
IDD33
3.3V supply current
1 Output Enabled
3.3V supply current
2 Outputs Enabled
(1)
(2)
(1) (2)
Min
Typ
Max
1.25 Gbps
87
94
2.5 Gbps
95
105
3.125 Gbps
101
112
1.25 Gbps
126
135
2.5 Gbps
136
145
3.125 Gbps
142
152
1.25 Gbps
74
85
2.5 Gbps
74
85
3.125 Gbps
74
85
1.25 Gbps
80
92
2.5 Gbps
80
92
3.125 Gbps
80
92
Unit
mA
mA
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
5
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
Power Supply Specifications (continued)
Over recommended operating supply and temperature ranges unless otherwise specified. (1) (2)
Symbol
PD
Parameter
Condition
Power Consumption
1 Output Enabled
Power Consumption
2 Output Enabled
Min
Typ
Max
1.25 Gbps
460
540
2.5 Gbps
485
560
3.125 Gbps
500
575
1.25 Gbps
580
670
2.5 Gbps
605
695
3.125 Gbps
620
710
Unit
mW
LVCMOS Electrical Specifications
Over recommended operating supply and temperature ranges unless otherwise specified. Applies to GPIO0, GPIO1, GPIO2,
RESET, LOCK, RS, and DC_BAL. (1) (2) (3)
Symbol
Parameter
Conditions
Min
Typ
Max
Units
VIH
High Level Input Voltage
2.0
VDD
V
VIL
Low Level Input Voltage
0
0.8
V
VOH
High Level Output Voltage
IOH = -2mA
VOL
Low Level Output Voltage
IOL = 2mA
VCL
Input Clamp Voltage
ICL = -18mA
IIN
Input Current
VIN = 0.4V, 2.5V, or VDD
IOS
Output Short Circuit Current
VOUT = 0V
(1)
(2)
(3)
(4)
2.7
3.3
V
0.3
-0.79
-35
V
35
μA
42
(4)
V
-1.5
mA
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD and ΔVOD.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Output short circuit current (IOS) is specified as magnitude only, minus sign indicates direction only.
SMBus Electrical Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
VSIL
Data, Clock Input Low Voltage
VSIH
Data, Clock Input High Voltage
VSDD
Nominal Bus Voltage
iSLEAKB
Input Leakage Per Bus Segment
CSI
Capacitance for SDA and SCLK
(1)
(2)
(3)
(4)
(5)
6
Conditions
See
(4) (5)
,
(1) (2) (3)
Min
Typ
Max
Units
0.8
V
2
VSDD
V
2.375
3.6
V
±200
μA
10
pF
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD and ΔVOD.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Recommended value, parameter is not tested.
Recommended maximum capacitance load per bus segment is 400 pF.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
SMBus Timing Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
(1) (2)
Conditions
Min
Typ
Max
Units
100
kHz
tSMB
Bus Operating Frequency
10
tBUF
Bus Free Time between Stop and Start Condition
4.7
μs
tHD:STA
Hold time after (repeated) start condition. After this
period, the first clock is generated.
4.0
μs
tSU:STA
Repeated Start Condition Setup Time
4.7
μs
tSU:STO
Stop Condition Setup Time
4.0
μs
tHD:DAT
Data Hold Time
300
ns
tSU:DAT
Data Setup Time
250
ns
tLOW
Clock Low Time
4.7
tHIGH
Clock High Time
4.0
tF
Clock/Data Fall Time
tR
Clock/Data Rise Time
tSU:CS
SMB_CS Setup Time
tPOR
Time in which the device must be operation after
power on
(1)
(2)
(3)
μs
20% to 80%
50
μs
300
ns
1000
ns
500
ms
30
See
(3)
ns
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Parameter is ensured by characterization and is not tested at production.
LVDS Electrical Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
Conditions
VTH
Differential Input High Threshold
VTL
Differential Input Low Threshold
VLVCM
LVDS Input Common Mode Voltage
VLVOS
LVDS Input Loss of Signal
LVDS input loss of signal level.
See (4)
RLVIN
Input Impedance
Internal LVDS input termination
between differential pairs.
(1)
(2)
(3)
(4)
(1) (2) (3)
Min
0.05V < VLVCM < VDD25 – 0.05V
Typ
Max
Units
+100
mV
-100
mV
0.05
VDD25 –
0.05
20
85
100
V
mVP-P
115
Ω
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD and ΔVOD.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
If input LVDS signal is below 20mVP-P, loss of signal (LOS) is detected. The device will flag a valid input signal if the signal level is
above 100mVP-P
LVDS Timing Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
Conditions
f
Input DDR Clock (TxCLKIN) Frequency Range
tCIP
TxCLKIN Period
(1)
(2)
(1) (2)
Min
Typ
125
See Figure 3
3.2
2T
Max
Units
312.5
MHz
8
ns
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
7
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
LVDS Timing Specifications (continued)
Over recommended operating supply and temperature ranges unless otherwise specified. (1) (2)
Symbol
Parameter
tCIT
TxCLKIN Transition Time
tXIT
TxIN Transition Time
tCIH
TxCLKIN High Time
tCIL
Conditions
See Figure 2
See (3)
Min
Typ
Max
Units
0.5
1.0
3.0
ns
3
ns
0.15
0.7T
T
1.3T
ns
TxCLKIN Low Time
0.7T
T
1.3T
ns
tSTC
TxIN Setup to TxCLKIN
-550
tHTC
TxIN Hold to TxCLKIN
900
tLVDLS
LVDS Input Clock Delay Step Size
(3)
See Figure 3
Programmable through the SMBus,
register 30'h
Default setting = 011'b [7:5]
ps
ps
100
ps
Parameter is ensured by characterization and is not tested at production.
CML Electrical Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
ROT
Output Terminations
ΔROT
Mismatch in Output Termination Resistors
VOD
Output Differential Voltage Swing
(1)
(2)
(3)
(1) (2) (3)
Conditions
Min
Typ
Max
Units
On chip termination from TxOUT0/1 +
and TxOUT0/1 - to VDD25
50Ω mode
40
50
60
Ω
75Ω mode
60
75
90
Ω
5
%
1450
mVP-P
Based on VOD_CTRL = 9.1 kΩ
1175
1350
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground
except VOD and ΔVOD.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
CML Timing Specifications
Over recommended operating supply and temperature ranges unless otherwise specified.
Symbol
Parameter
(1) (2)
Conditions
LR
Line Rate
Tested with alternating 1-0 pattern.
tOS
Output Overshoot
See
tR
Differential Low to High Transition Time
tF
Differential High to Low Transition Time
tRFMM
Mismatch in Rise/Fall Time
tDE
De-emphasis width
tBIT
Serializer Bit Width
tSD
Serializer Propagation Delay – Latency
(1)
(2)
(3)
8
See
See
Min
Typ
Max
Units
3.125
Gbps
10
%
60
90
ps
60
90
ps
15
ps
1.25
(3)
(3)
(3)
Measured from zero-crossing at rising
edge to 80% of VOD from zerocrossing at falling edge. TDE is
measured at the High setting during
test.
Depends on mode — see Table 3
1
UI
0.2 x
tCIP
ns
(10 –
14) T+
5.5
ns
The Electrical Characteristics tables list ensured specifications under the listed Recommended Operating Conditions except as
otherwise modified or specified by the Electrical Characteristics Conditions and/or Notes. Typical specifications are estimations only and
are not ensured.
Typical values represent most likely parametric norms for VCC = +3.3V and TA = +25°C, and at the Recommended Operation Conditions
at the time of product characterization and are not ensured.
Parameter is ensured by characterization and is not tested at production.
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
CML Timing Specifications (continued)
Over recommended operating supply and temperature ranges unless otherwise specified. (1) (2)
Symbol
tJIND
tJINR
tJINT
Parameter
Conditions
Serializer Output Deterministic Jitter
Serializer Output Random Jitter
Peak-to-peak Serializer Output Jitter
λTXBW
Jitter Transfer Function -3 dB Bandwidth
δTX
Jitter Transfer Function Peaking
(4)
(4)
Min
Typ
Max
Units
Serializer output intrinsic deterministic
jitter. Measure with PRBS-7 test
pattern De-emphasis disabled.
See (3)
1.25 Gbps
10
ps
2.5 Gbps
24
ps
3.125 Gbps
21
ps
Serializer output intrinsic random
jitter. Bit error rate ≥10-15.
Alternating–10 pattern. De-emphasis
disabled.
See (3)
1.25 Gbps
1.3
psRMS
2.5 Gbps
1.15
psRMS
3.125 Gbps
1.14
psRMS
Serializer output peak-to-peak jitter
includes deterministic jitter, random
jitter, and jitter transfer from serializer
input. Measure with PRBS-7 test
pattern. Bit error rate ≥10-15. Deemphasis disabled.
See (3)
1.25 Gbps
28
ps
2.5 Gbps
38
ps
3.125 Gbps
35
ps
1.25 Gbps
3.125 Gbps
100
300
kHz
kHz
0.5
dB
(4)
Parameter is ensured by characterization and is not tested at production.
Timing Diagrams
SMB_CS
tSU:CS
tLOW
tHIGH
tR
SCK
tHD:STA
tBUF
tF
tHD:DAT
tSU:STA
tSU:DAT
tSU:STO
SDA
SP
ST
SP
ST
Figure 1. SMBus timing parameters
80%
80%
TXCLK
20%
20%
tCIT
tCIT
Figure 2. Serializer Input Clock Transition Time
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
9
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
tCIP/2
+100 mV
TXCLK
0V
-100 mV
tCIL, tCIH
tSTC
tHTC
Hold
Setup
TXn
0V
Figure 3. Serializer (LVDS Interface) Setup/Hold and High/Low Times
tCIP/2
TxCLKIN
Clock Delay
(Programmable)
Programmable
Delay Clock
(Internal)
tHTC
tSTC
TxIN
Valid Data
Window
Figure 4. LVDS Input Clock Delay
TXN
Symbol N
Symbol N+1
Symbol N+2
Symbol N+3
Symbol N+4
tSD
TXCLK
Symbol N-4
Symbol N-3
Symbol N-1
Symbol N-2
Symbol N
TXOUT
Figure 5. Propagation Delay Timing Diagram
10
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Previous Cycle
Current Cycle
Next Cycle
Input Transmit Clock
LVDS Data-0
A0
A1
A2
A3
LVDS Data-1
B0
B1
B2
B3
LVDS Data-2
C0
C1
C2
C3
LVDS Data-3
D0
D1
D2
D3
LVDS Data-4
E0
E1
E2
E3
Last Bit Out
First Bit Out
E3
D3
B3
C3
A3
E2
D2
B2
C2
A2
E1
D1
B1
C1
A1
E0
D0
B0
C0
A0
Serialized CML Output
Figure 6. 5-Bit Parallel LVDS Inputs Mapped to CML Output
FUNCTIONAL DESCRIPTION
POWER SUPPLIES
The DS32EL0421 and DS32ELX0421 have several power supply pins, at 2.5V as well as 3.3V. It is important
that these pins all be connected and properly bypassed. Bypassing should consist of parallel 4.7μF and 0.1μF
capacitors as a minimum, with a 0.1μF capacitor on each power pin. A 22 μF capacitor is required on the
VDDPLL pin which is connected to the 3.3V rail.
These devices have a large contact in the center on the bottom of the package. This contact must be connected
to the system GND as it is the major ground connection for the device.
POWER UP
It is recommended, although not necessary, to bring up the 3.3V power supply before the 2.5V supply. If the 2.5V
supply is powered up first, an initial current draw of approximately 600mA from the 2.5V rail may occur before
settling to its final value. Regardless of the sequence, both power rails should monotonically ramp up to their final
values.
POWER MANAGEMENT
These devices have two methods to reduce power consumption. To enter the first power save mode, the on
board host FPGA or controlling device can cease to output the DDR transmit clock. To further reduce power
consumption, write 40'h to register 26'h and 10'h to register 01'h. This will put the device in its lowest power
consumption mode.
RESET
There are three ways to reset these devices. A reset occurs automatically during power-up. The device can also
be reset by pulling the RESET pin low, with normal operation resuming when the pin is driven high again. The
device can also be reset by writing to the reset register. This reset will put all of the register values back to their
default values, except it will not affect the address register value if the SMBus default address has been
changed.
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
11
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
LVDS INPUTS
The DS32EL0421 and DS32ELX0421 have standard 2.5V LVDS inputs which are compliant with ANSI/TIA/EIA644. These inputs have internal 100Ω termination resistors. It is recommended that the PCB trace between the
FPGA and the serializer be less than 40-inches. Longer PCB traces may degrade the quality of the input signal.
The connection between the host and the DS32EL0421 or DS32ELX0421 should be over a controlled
impedance transmission line with impedance that matches the termination resistor – usually 100Ω. Setup and
hold times are specified in the LVDS Timing Specifications, however the clock delay can be adjusted by writing
to register 30’h.
LOOP FILTER
The DS32EL0421 and DS32ELX0421 have an internal PLL which is used to generate the serialization clock from
the parallel clock input. The loop filter for this PLL is external; and for optimum results, a 100nF capacitor and a
1.5 kΩ resistor in series should be connected between pins 26 and 27. See typical interface circuit (Figure 11).
CML LAUNCH AMPLITUDE
The launch amplitude of the CML output(s) is controlled by placing a single resistor from the VOD_CTRL pin to
ground. Use the following equation to obtain the desired VOD by selecting the corresponding resistor value.
R = (1400 mV / VOD) x 9.1 kΩ
(1)
The CML output launch amplitude can also be adjusted by writing to SMBus register 69'h, bits 2:0. This register
is meant to assist system designers during the initial prototype design phase. For final production, it is
recommended that the appropriate resistor value be selected for the desired VOD and that register 69'h be left to
its default value.
REMOTE SENSE
The remote sense feature can be used when a DS32EL0421 or DS32ELX0421 serializer is directly connected to
a DS32EL0124 or DS32ELX0124 deserializer. Active components in the signal path between the serializer and
the deserializer may interfere with the back channel signaling of the devices.
When remote sense is enabled, the serializer will cycle through four states to successfully establish a link and
align the data. The state diagram for the serializer is shown in Figure 7. The serializer will remain in the low
power IDLE state until it receives an input clock. Once the PLL of the serializer has locked to the input clock, the
device will enter the LINK DETECT state. While in this state, the serializer will monitor the line to see if the
deserializer is present. If a deserializer is detected, the serializer will enter the LINK ACQUISITION state. The
serializer will transmit the entire training pattern and then enter the NORMAL state. If the deserializer is unable to
successfully lock or maintain lock it will break the link, sending the serializer back to the IDLE or LINK DETECT
states.
With the Remote Sense feature active, the serializer can be forced out of lock due to events on the high speed
serial line in two ways, a serial channel reset signal is sent upstream from the deserializer or the near end
termination detect circuit signals and open termination was detected. The upstream signal sent from the
deserializer that resets the serializer is called the link detect signal. Since the serializer and deserializer may
power up at different times, the deserializer will transmit this link detect signal periodically, once it detects that a
serializer is active on the other side of the high speed line. When a serializer receives the link detect signal, it will
return to the LINK DETECT state. The near end open termination detection circuit will trigger only for near end
open termination events, such as unplugging the cable on the serializer end of the line.
DC-BALANCE ENCODER
The DS32EL0421 and DS32ELX0421 have a built-in DC-balance encoder to support AC-coupled applications.
When enabled, the input signal on TXIN4+/- is treated as a data valid bit. If TXIN4+/- is low, then the four bit
nibbles from TXIN0-TXIN3 are taken to form a 16 bit word. This 16 bit word is processed as two 8 bit words and
converted to two 10 bit words by using the standard 8b/10b data coding scheme. The two 10 bit words are then
combined to create a 20 bit code. This 20 bit word is serialized and driven on the output. The nibble taken in on
the rising edge of the clock is the most significant nibble and the nibble taken in on the falling edge is the least
significant nibble. If TXIN4+/TXIN4- is high, then the inputs TXIN0 -TXIN3 are ignored and a programmable DCbalanced SYNC character is inserted in the output stream. The default character is a K28.5 code. In order to
send other K codes, they must first be programmed into the serializer via the SMBus. The SMBus registers
allows for only a single programmable character.
12
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Power-On/Reset
TxCLKIN does
not exist
IDLE
RS: 1, DC_B: 0
RS: 1, DC_B: 1
TxCLKIN exist
LINK
DETECT
Link Detect
fail
LINK
ACQUISITION
NORMAL
Figure 7. Serializer State Diagram
SCRAMBLER and NRZI Encoder
The CDR of the DS32EL0124 and the DS32ELX0124 expect a transition density of 20% for a period of 200 μs. If
the scrambler and NRZI encoder are enabled, the raw or DC-balanced serialized data is scrambled to improve
transition density. The scrambler accepts 20 bits of data and encodes it using the polynomial X9 + X4 + 1. The
data can then be sent to the NRZ-to-NRZI converter before being output.
Enabling the scrambler can help to lower EMI emissions by spreading the spectrum of the data. Scrambling also
creates transitions for the deserializer’s CDR to properly lock onto.
The scrambler and NRZI encoder are enabled or disabled by default depending on how the DC_B and RS pins
are configured. To override the default scrambler setting two register writes must be performed. First, write to
register 22’h and set bit 3 to unlock the scrambler register. Next write to register 21’h and change bit 4 to the
desired value. The NRZI encoder can be enabled or disabled independently of the scrambler by controlling bit 7
of register 21'h and bit 4 of register 22'h.
CML OUTPUT DATA INTERFACING
The serial outputs provide low-skew differential signals. Internal resistors connected from TxOUTn+ and
TxOUTn- to VDD25 terminate the outputs. The output level can be programmed by adjusting the pull-down
resistor to the VOD_CTRL pin. The output terminations can also be programmed to be either 50 Ω or 75 Ω.
The output buffer consists of a current mode logic (CML) driver with user configurable de-emphasis control,
which can be used to optimize performance over a wide range of transmission line lengths and attenuation
distortions resulting from low cost CAT(-5, -6, -7) cable or FR–4 backplane. Output de-emphasis is user
programmable through either device pins DE_EMPH0 and DE_EMPH1 or SMBus interface. Users can control
the strength of the de-emphasis to optimize for a specific system environment. Please see Table 1 for details.
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
13
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
Table 1. De-Emphasis Control Table
DE_EMPH[1:0]
Output De-Emphasis Level
00'b
Off
01'b
Low
10'b
Medium
11'b
High
The DS32ELX0421 provides a secondary serial output, supporting redundancy applications. The redundant
output driver can be enabled by setting TXOUT1_EN pin to HIGH or by activating it through the SMBus reigsters.
DEVICE CONFIGURATION
There are four ways to configure the DS32EL0421 and DS32ELX0421 serializers, these combinations are shown
in Table 2. Refer to Figure 7 to see how the combinations of the RS and DC_B pins change the link startup
behavior of the serializers. When connecting to a deserializer other than the DS32EL0124 or DS32ELX0124,
Remote Sense should be disabled. The scrambler and NRZI encoder shown in Table 2 can be enabled or
disabled through register programming.
When Remote Sense is enabled, with RS pin tied low, the serializer must be connected directly to a
DS32EL0124 or DS32ELX0124 deserializer without any active components between them. The Remote Sense
module features an upstream communication method for the serializer and deserializer to communicate. This
feature is used to pass link status information between the 2 devices. When Remote Sense is enabled the
serializer will send a training pattern to the deserializer to establish lock and lane alignment.
If DC-Balance is enabled, a maximum of 4 parallel LVDS lanes can be used to receive data. The fifth lane
(TXIN4±) is used for Data Valid signaling. Each time a serializer establishes a link to a deserializer with DCBalance enabled and Remote Sense disabled, the Data Valid input to the serializer must be held high for 110
LVDS clock periods. If the Data Valid input to the serializer is logic HIGH, then SYNC characters are transmitted.
If the deserializer receives a SYNC character, then the LVDS data outputs will all be logic low and the Data Valid
output will be logic high. If the deserializer detects a DC-Balance code error, the output data pins will be set to
logic high with the Data Valid output also set to logic high.
In the case where DC-Balance is enabled and Remote Sense is disabled, with RS set to high and DC_B set to
low, it is recommended that the host device periodically toggle the Data Valid input to the serializer, to transmit
SYNC symbols on the line, to ensure that the deserializer is and remains locked. In this configuration the
deserializer or receiving device does not have a way to directly notify the serializer if it has lost lock. Periodically
sending SYNC symbols will allow the receiving system to reacquire lock if a problem has occurred. With these
pin settings the DS32EL0421/DS32ELX0421 and DS32EL0124/DS32ELX0124 devices can interface with other
active component in the high speed signal path, such as fiber modules.
When both Remote Sense and DC-Balance are disabled, RS and DC_B pins set to high, the LVDS lane
alignment is not maintained. In this configuration, data formatting is handled by an FPGA or external source. This
pin setting combination also allows for the DS32EL0421/DS32ELX0421 devices to interface with active
components other than the DS32EL0124/DS32ELX0124 in the high speed signal path. In this configuration the
host device is responsible for DC balancing the data in an AC coupled application.
14
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Table 2. Device Configuration Table
Remote Sense Pin
(RS)
DC-Balance Pin (DC_B)
Configuration
0
0
Remote Sense enabled
DC-Balance enabled
Data Alignment
Scrambler and NRZI encoder disabled by default
0
1
Remote Sense enabled
DC-Balance disabled
Data Alignment
Scrambler and NRZI encoder enabled by default
1
0
Remote Sense disabled
DC-Balance enabled
Data Alignment
Scrambler and NRZI encoder enabled by default
1
1
Remote Sense disabled
DC-Balance disabled
No Data Alignment
Scrambler and NRZI encoder disabled by default
SMBus INTERFACE
The System Management Bus interface is compatible to SMBus 2.0 physical layer specification. The use of the
Chip Select signal is required. Holding the SMB_CS pin HIGH enables the SMBus port, allowing access to the
configuration registers. Holding the SMB_CS pin LOW disables the device's SMBus, allowing communication
from the host to other slave devices on the bus. In the STANDBY state, the System Management Bus remains
active. When communication to other devices on the SMBus is active, the SMB_CS signal for the serializer must
be driven LOW.
The address byte for all DS32EL0421 and DS32ELX0421 devices is AE'h. Based on the SMBus 2.0
specification, these devices have a 7-bit slave address of 1010111'b. The LSB is set to 0'b (for a WRITE), thus
the 8-bit value is 1010 1110 'b or AE'h.
The SCK and SDA pins are 3.3V LVCMOS signaling and include high-Z internal pull up resistors. External low
impedance pull up resistors maybe required depending upon SMBus loading and speed. Note, these pins are not
5V tolerant.
Transfer of Data via the SMBus
During normal operation the data on SDA must be stable during the time when SCK is HIGH.
There are three unique states for the SMBus:
START
A HIGH to LOW transition on SDA while SCK is HIGH indicates a message START condition
STOP
A LOW to HIGH transition on SDA while SCK is HIGH indicates a message STOP condition.
IDLE
If SCK and SDA are both high for a time exceeding tBUF from the last detected STOP condition or if they are HIGH for a total
exceeding the maximum specification for tHIGH then the bus will transfer to the IDLE state.
SMBus Transactions
The devices support WRITE and READ transactions. See Register Description Table for register address, type
(Read/ Write, Read Only), default value and function information.
Writing to a Register
To
1.
2.
3.
4.
5.
write a register, the following protocol is used (see SMBus 2.0 specification).
The Host (Master) selects the device by driving its SMBus Chip Select (SMB_CS) signal HIGH.
The Host drives a START condition, the 7-bit SMBus address, and a “0” indicating a WRITE.
The Device (Slave) drives the ACK bit (“0”).
The Host drives the 8-bit Register Address.
The Device drives an ACK bit (“0”).
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
15
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
6.
7.
8.
9.
The
The
The
The
www.ti.com
Host drive the 8-bit data byte.
Device drives an ACK bit (“0”).
Host drives a STOP condition.
Host de-selects the device by driving its SMBus CS signal Low.
The WRITE transaction is completed, the bus goes IDLE and communication with other SMBus devices may
now occur.
Reading a Register
To read a register, the following protocol is used (see SMBus 2.0 specification).
1. The Host (Master) selects the device by driving its SMBus Chip Select (SMB_CS) signal HIGH.
2. The Host drives a START condition, the 7-bit SMBus address, and a “0” indicating a WRITE.
3. The Device (Slave) drives the ACK bit (“0”).
4. The Host drives the 8-bit Register Address.
5. The Device drives an ACK bit (“0”).
6. The Host drives a START condition.
7. The Host drives the 7-bit SMBus Address, and a “1” indicating a READ.
8. The Device drives an ACK bit “0”.
9. The Device drives the 8-bit data value (register contents).
10. The Host drives a NACK bit “1”indicating end of the READ transfer.
11. The Host drives a STOP condition.
12. The Host de-selects the device by driving its SMBus CS signal Low.
The READ transaction is completed, the bus goes IDLE and communication with other SMBus devices may now
occur.
SMBus Configurations
Many different configurations of the SMBus are possible and depend upon the specific requirements of the
applications. Several possible applications are described.
Configuration 1
The deserializer SMB_CS may be tied High (always enabled) since it is the only device on the SMBus. See
Figure 8.
Configuration 2
Since the multiple SER devices have the same address, the use of the individual SMB_CS signals is required.
To communicate with a specific device, its SMB_CS is driven High to select the device. After the transaction is
complete, its SMB_CS is driven Low to disable its SMB interface. Other devices on the bus may now be selected
with their respective chip select signals and communicated with. See Figure 9.
Configuration 3
The addressing field is limited to 7-bits by the SMBus protocol. Thus it is possible that multiple devices may
share the same 7-bit address. An optional feature in the SMBus 2.0 specification supports an Address Resolution
Protocol (ARP). This optional feature is not supported by the DS32EL0421/DS32ELX0421 devices. Solutions for
this include: the use of the independent SMB_CS signals, independent SMBus segments, or other means.
16
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
SMBus
Device
FPGA
Host
3V3
SMB_CS
SDA
LVCMOS GPIO
SMBus Interface
SCK
3V3
Figure 8. SMBus Configuration 1
SMBus
Device
FPGA
Host
SMBus
Device
SMBus
Device
SMB_CS
SDA
SCK
SMB_CS
SDA
SCK
SMB_CS
SDA
LVCMOS GPIO
SMBus Interface
SCK
3V3
Figure 9. SMBus Configuration 2
SMBus
Device
SMBus
Device
3V3
SMB_CS
SDA
SCK
SMB_CS
3V3
SDA
SMB_CS
SDA
SCK
LVCMOS GPIO
SMBus Interface
SMBus
Device
3V3
3V3
SCK
FPGA
Host
Figure 10. SMBus Daisy Chained CS Configuration
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
17
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
PROPAGATION DELAY
Once the serializer is locked, the amount of time it takes for a bit to travel into the device through the DDR LVDS
inputs and out through the CML serial output is defined to be the propagation delay. The propagation delay
through the DS32EL0421/DS32ELX0421 due to the analog circuitry is considered negligible compared to the
time delay caused by the digital components. The information presented in this section allows system designers
to predict the propagation delay through the device in terms of clock cycles which are proportional to the high
speed serial line rate.
Each clock cycle shown in Table 3 is defined to be 1/2 tCIP. Note at 3.125Gbps, tCIP is 312.5MHz, T is 1/2 tCIP or
156.25MHz which is 6.40ns per clock..
Table 3. Serializer Propagation Delay
Config. Pins
(DC_B, RS)
LVDS
Interface
DC Balance
Encoder
Scrambler
NRZ
Encoder
CML
interface
Analog
Delay
Total
Propagation
Delay
Data Flow (left to right)
0, 0
3 clocks
1 clock
–
–
5 – 6 clocks
2 clocks
+ ~5.5ns
11 – 12 clocks
+ ~5.5ns
0, 1
3 clocks
1 clock
1 clock
1 clock
5 – 6 clocks
2 clocks
+ ~5.5ns
13 – 14 clocks
+ ~5.5ns
1, 0
3 clocks
–
1 clock
1 clock
5 – 6 clocks
2 clocks
+ ~5.5ns
12 – 13 clocks
+ ~5.5ns
1, 1
3 clocks
–
–
–
5 – 6 clocks
2 clocks
+ ~5.5ns
10 – 11 clocks
+ ~5.5ns
Application Information
GPIO PINS
The GPIO pins can be useful tools when debugging or evaluating the system. For specific GPIO configurations
and functions refer to registers 2, 3, 4, 5 and 6 in the device register map.
GPIO pins are commonly used when there are multiple serializers on the same SMBus. In order to program
individual settings into each serializer, they will each need to have a unique SMBus address. To reprogram
multiple serializers on a single SMBus, configure the first serializer such that the SMBus lines are connected to
the FPGA or host controller. The CS pin of the second serializer should be tied to GPIO0 of the first serializer,
with the CS pin of the next serializer tied to GPIO0 of its preceding serializer. By holding all of the GPIO0 pins
low, the first serializer’s address may now be reprogrammed by writing to register 0. The first serializer’s GPIO
pin can now be asserted and the second serializer’s address may now be reprogrammed.
HIGH SPEED COMMUNICATION MEDIA
Using the serializer’s integrated de-emphasis blocks in combination with the DS32EL0124 or DS32ELX0124’s
integrated equalization blocks allows data to be transmitted across a variety of media at high speeds. Factors
that can limit device performance include excessive input clock jitter, noisy power rails, EMI from nearby noisy
components and poor layout techniques. Although many cables contain wires of similar gauge and shielding,
performance can vary greatly depending on the quality of the connector.
REDUNDANCY APPLICATIONS
The DS32ELX0421 has two high speed CML serial outputs. SMBus register control allows the device to use a
single output exclusively, or both outputs simultaneously. This allows a single serializer to transmit data to two
independant receiving systems, a primary and secondary endpoint. Some applications require a redundancy
measure in case the primary signal path is compromised. The secondary output can be activated “on-the-go”, if a
problem is detected on the primary link. See the Redundancy / Fail Over Configuration section located under
Register Recipes.
18
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
LINK AGGREGATION
Multiple DS32EL0421/DS32ELX0421 serializers and D32EL0124/DS32ELX0124 deserializers can be
aggregated together if an application requires a data throughput of more than 3.125 Gbps. By utilizing the data
valid signal of each device, the system can be properly deskewed to allow for a single cable, such as CAT-6,
DVI-D, or HDMI, to carry data payloads beyond 3.125 Gbps.
Link aggregation configurations can also be implemented in applications which require longer cable lengths. In
these type of applications the data rate of each serializer and deserializer chipset can be reduced, such that the
applications' net data throughput is still the same. Since each high speed channel is now operating at a fraction
of the original data rate, the loss over the cable is reduced, allowing for greater lengths of cable to be used in the
system.
For more information regarding link aggregation please see SNLA109, Expanding the Payload with TI's FPGALink DS32ELX0421 and DS32ELX0124 Serializer and Deserializer.
LAYOUT GUIDELINES
It is important to follow good layout practices for high speed devices. The length of LVDS input traces should not
exceed 40 inches. In noisy environment the LVDS traces may need to be shorter to prevent data corruption due
to EMI. Noisy components should not be placed next to the LVDS or CML traces. The LVDS and CML traces
must have a controlled differential impedance of 100 Ω. Do not place termination resistor at the LVDS inputs or
CML outputs, the DS32EL0421 and DS32ELX0421 have internal termination resistors. It is recommended to
avoid using vias. Vias create an impedance mismatch in the transmission line and result in reflections, which can
greatly lower the maximum distance of the high speed data link. If vias are required, they should be placed
symmetrically on each side of the differential pair. For more tips and detailed suggestions regarding high speed
board layout principles, please consult the LVDS Owner’s Manual.
2.5V 3.3V
0.1 PF
0.1 PF
7, 15, 18,
25, 35
43
46
44
41
FPGA Host
42
39
40
37
38
1, 36
VCC33
48
45
+
TXIN4
-
VCC25
47
GND
49
TXOUT0
+
TXIN3
-
+
-
TXOUT1 +
-
16
17
19
20
+
TXIN2
-
3.3V
+
TXIN1
-
VDDPLL
1:
28
22 PF
+
TXIN0
-
DS32ELX0421
+
TXCLKIN
-
VOD_CTRL
14
27
9.1 k:
1.5 k:
LF_CP
30
31
LF_REF
RESET
26
100 nF
LOCK
32
GPIO0
3.3V
5
3
4
GPIO1
11
GPIO2
RS
DC_B
SDA
33
SCK
34
SMB_CS
6
3.3V
Figure 11. Typical Interface Circuit
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
19
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
Typical Performance Characteristics
The eye diagrams shown below illustrate the typical performace of the DS32ELX0421/DS32EL0421 configured with RS =
0,DC_B = 0, for the conditions listed below each figure. The PRBS-15 data was generated by a low cost FPGA, which used
an LMK03000C to generate the various clock frequencies.
20
Figure 12. CML Serial Differential Output 1.25 Gbps
Figure 13. CML Serial Differential Output 3.125 Gbps
Figure 14. CML Serial Singled Ended Output (+) 1.25 Gbps
Figure 15. CML Serial Single Ended Output (+) 3.125 Gbps
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Register Map
The register information for the serializer is shown in the table below. Some registers have been omitted or
marked as reserved; these are for internal testing and should not be written to. Some register bits require an
override bit to be set before they can be written to.
Addr
(Hex)
Name
00
Device ID
01
Reset
02
03
04
GPIO0 Config
GPIO1 Config
GPIO2 Config
Bits
Field
R/W
Default
Description
R/W
57'h
Some systems will use all 8 bits as the device ID. This will
shift the value from 57’h to AE’h
7:1
SMBus Address
0
Reserved
0
7:5
Reserved
0
4
Analog Disable
3:1
Reserved
0
0
Software Reset
0
1: Reset the device. Does not affect device ID.
7:4
GPIO0 Mode
R/W
0
0000: GP out register
0001: Link loss indicator
0011: TxCLKIN loss of signal
0100: TxCLKIN detect
All others: Reserved
3:2
GPIO0 R Enable
R/W
01'b
1
Input Enable
R/W
0
0
Output Enable
R/W
1'b
7:4
GPIO1 Mode
R/W
0
0000: Power on reset
0001: GP out register
0010: PLL lock indicator
0011: TxIN0 loss of signal
0100: TxIN1 loss of signal
0101: TxIN2 loss of signal
0110: TxIN3 loss of signal
0111: TxIN4 loss of signal
All others: Reserverd
3:2
GPIO1 R Enable
R/W
01'b
00: Pullup/down disabled
01: Pulldown enabled
10: Pullup enabled
11: Reserved
1
Input Enable
R/W
0
0
Output Enable
R/W
1'b
7:4
GPIO2 Mode
R/W
0
3:2
GPIO2 R Enable
R/W
01'b
1
Input Enable
R/W
0
0
Output Enable
R/W
1'b
R/W
0
1: Disables analog blocks. Power save feature
00: Pullup/down disabled
01: Pulldown enabled
10: Pullup enabled
11: Reserved
0: Input buffer disabled
1: Input buffer enabled
0: OutputTtri-State™
1: Output enabled
0: Input buffer disabled
1: Input buffer enabled
0: Output Tri-State™
1: Output enabled
0000: GP out register
0001: Always on clock out
0010: Parallel-to-serial clock out
0100: Digital clock out
All others: Reserverd
00: Pullup/down disabled
01: Pulldown enabled
10: Pullup enabled
11: Reserved
0: Input buffer disabled
1: Input buffer enabled
0: Output Tri-State™
1: Output enabled
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
21
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
Addr
(Hex)
Name
05
GP In
06
GP Out
Bits
www.ti.com
Field
R/W
Default
Description
7:3
Reserved
0
2
GP In 2
R
0
Input value on GPIO2
1
GP In 1
R
0
Input value on GPIO1
0
GP In 0
R
0
Input value on GPIO0
7:3
Reserved
2
GP Out 2
R/W
0
Output value on GPIO2
1
GP Out 1
R/W
0
Output value on GPIO1
0
GP Out 0
R/W
0
Output value on GPIO0
7:3
Reserved
2
Pin Override
R/W
0
0: Pin values determine setting
1: Register overrides pin values
1:0
De-emphasis
level
R/W
0
00:
01:
10:
11:
7
NRZI enable
R/W
0
1: Enable NRZI, if override bit is set
6
DV disable
R/W
0
1: Disable Data Valid
5
Reserved
R/W
0
4
Scrambler Enable
R/W
0
1: Scrambler enable, requires override bit to change
setting
3
DC Bal encoder
bypass
R/W
0
1: Bypass encoder, requires override bit to change setting
2
Training
Sequence Enable
R/W
0
1: Enable training sequence, requires override bit to
change setting
1:0
Device
Configuration
R/W
0
MSB: Remote Sense enable, active low
LSB: DC balance encoder enable, active low
Requires override bit to change settings through registers.
Normally controlled by pins. See Table 2 for more
information.
7:5
Reserved
4
NRZ bypass
override
R/W
0
1: Unlock reg 21’h bit 7
3
Scrambler bypass
override
R/W
0
1: Unlock reg 21’h bit 4
2
DC Bal encoder
bypass override
R/W
0
1: Unlock reg 21’h bit 3
1
Training
sequence enable
override
R/W
0
1: Unlock reg 21’h bit 2
0
Config pin
override
R/W
0
1: Unlock reg 21’h bits 1 and 0
TxCLKIN Delay
Bypass
R/W
0
0: TxCLKIN delay enable
1: Bypass TxCLKIN delay
0
07–1F Reserved
20
21
22
De-Emphasis
Device Config
Device Config
Override
0
No de-emphasis
Low
Medium
High
0
23 Reserved
24
LVDS Clock Delay 7
Enable
6:0
Reserved
0
25 Reserved
22
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
Addr
(Hex)
26
27
28
29
2A
SNLS282F – MAY 2008 – REVISED APRIL 2013
Name
Power Down
Event Disable
LVDS Operation
Loss of Signal
Status
Event Status
Bits
Field
R/W
Default
Description
7
Channel Reset
R/W
0
1: Reset high speed channel. Self-clearing bit.
6
Clock Powerdown
R/W
0
1: Power down parallel, parallel-to-serial, and always on
clock
5
LVDS Clock
enable
R/W
1'b
0: Disable TxCLKIN
1: Enable TxCLKIN
4
TxIN4 Enable
R/W
1'b
0: Disable TxIN4
1: Enable TxIN4
3
TxIN3 Enable
R/W
1'b
0: Disable TxIN3
1: Enable TxIN3
2
TxIN2 Enable
R/W
1'b
0: Disable TxIN2
1: Enable TxIN2
1
TxIN1 Enable
R/W
1'b
0: Disable TxIN1
1: Enable TxIN1
0
TxIN0 Enable
R/W
1'b
0: Disable TxIN0
1: Enable TxIN0
7:5
Reserved
R/W
0
4
PLL Lock Disable
R/W
0
0: Count clock errors
1: Clock error count disabled
3
FIFO Error
Disable
R/W
0
0: Count FIFO erros 1: FIFO error count disabled
2
Parallel Clock
Detect Disable
R/W
0
0: Count clock detect errors
1: Clock detect count disabled
1
Clock Loss of
Signal Disable
R/W
0
0: Count clock los of signal errors
1: Clock loss of signal count disabled
0
Data Loss of
Signal Disable
R/W
0
0: Count data los of signal errors
1: Clock data of signal count disabled
7:2
Reserved
1
LVDS Loss of
Signal Preset
R/W
0
1: Preset signal for LVDS loss of signal register
0
LVDS Loss of
Signal Reset
R/W
0
1: Clear signal for LVDS loss of signal register
7:6
Reserved
5
Clock Loss of
Signal
R
0
0: Clock present
1: No clock present on TxCLKIN
4:0
Data Loss of
Signal
R
0
0: Data present
1: No data present on TxIN4:0
7:4
Reserved
3
TxCLKIN Detect
2
Reserved
1:0
Link Detect 1:0
0
0
0
R/W
0
0: TxCLKIN not detected
1: TxCLKIN detected
0
R/W
0
0: Link not detected
1: Link detected
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
23
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
Addr
(Hex)
Name
2B
Event Config
Bits
www.ti.com
Field
R/W
Default
Description
7
Reserved
6
PLL Lock Event
R/W
0
0: Count PLL lock events
1: Do not count PLL lock events
5
Link Event
R/W
0
0: Count link events
1: Do not count link events
4
Loss of Signal
Event
R/W
0
0: Count loss of signal events
1: Do not count loss of signal events
3
Event Count
Select
R/W
0
0: Select PLL event count for reading
1: Select link event count for reading
2
Clear PLL Error
Count
R/W
0
1: Reset PLL error count. Self clearing bit.
1
Clear Link Error
Count
R/W
0
1: Reset link error count. Self clearing bit.
0
Enable Count
R/W
0
0: Disable event counters
1: Enable event counters
Event Count
7:0
Event Counter
R
0
Analog Driver
7
Reserved
6
Reverse Data
Order
R/W
0
5:2
Reserved
R/W
0
1
Link Detect 1
R/W
0
Link detect value for channel 1
0
Link Detect 0
R/W
0
Link detect value for channel 0
7:6
Reserved
5
Output
Termination
R/W
1'b
0: 75 Ω terminations
1: 50 Ω terminations
4
Link Start
R/W
1'b
0: Start when TxOUT0 or TxOUT1 link
1: Start when TxOUT0 and TxOUT1 linke
3
Link Stop
R/W
1'b
0: Stop when TxOUT0 and TxOUT1 both links invalid
1: Stop when TxOUT0 or TxOUT1 break link, either link is
invalid
2
TxOUT Override
R/W
0
0: TxOUT0 enabled by default, TxOUT1_en pin controls
channel1
1: Override enable of TxOUT0 and TxOUT1
1
TxOUT1 Enable
R/W
0
0: TxOUT1 disabled
1: TxOUT1 enabled
For proper operation of TxOUT1, the TxOUT1_EN pin
must be held high.
0
TxOOUT0 Enable
R/W
0
0: TxOUT0 disabled
1: TxOUT0 enabled
7:5
TxCLKIN Delay
R/W
011’b
4:0
Reserved
7:3
Reserved
2:0
Amplitude Adjust
2C
0
2D Reserved
2E
2F
30
Tx Config
Clock Delay
0
0: Normal
1: Reverse output data order
0
000: Min clock delay, 350 ps
011: 725 ps
111: Max clock delay, 1225 ps
00010’b
31–68 Reserved
69
24
Output Amplitude
Adjust
Submit Documentation Feedback
0
R/W
011’b
000:
001:
010:
011:
100:
101:
110:
111:
Level
Level
Level
Level
Level
Level
Level
Level
7
8 (Highest output)
5
6 (Normal output)
4
3
2
1 (Lowest output)
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
DS32EL0421, DS32ELX0421
www.ti.com
SNLS282F – MAY 2008 – REVISED APRIL 2013
Register Recipes
Many features of the serializer contained within the SMBus registers require multiple writes to configure and
enable. This methodology was implemented to prevent accidental register writes from causing undesired device
behavior. Several recipes for common features are listed below. When experimenting with other SMBus register
features, be sure to read through the register map for override and enable bits.
SCRAMBLER OVERRIDE CONTROL
The scrambler’s default settings are described in the DEVICE CONFIGURATION section. However, the
scrambler’s setting can be overridden if desired.
Reg 22’h, write 08’h
Reg 21’h, write to bit 3 to enable/disable
75Ω MODE
The serializer can be programmed to interface with 75Ω media by using the recipe shown below. The inverting
serial output should be terminated when interfacing with single ended media.
Reg 2F’h, write 0 to bit 5
OUTPUT CHANNEL MUX CONTROL
DS32ELX0421 only. TxOUT0 is the output channel enabled by default. By using the external pin TxOUT1_EN,
TxOUT1 will be activated along with TxOUT0. If an application requires that only one channel be active at a time,
the following recipe allows for each channel to be enabled or disabled independent of the other.
Reg 2F’h, write 1’b to bit 2
Reg 2F’h, write to bits 1 or 0 to control the output channels
OUTPUT THE SERIAL CLOCK ON GPIO2
It is very helpful to be able to monitor high speed communication systems and observe their signal integrity.
Generally, this is done with a high speed real time oscilloscope or a sampling oscilloscope. Sampling
oscilloscopes require a reference clock to trigger on. The following recipe can be used to bring out the serial
clock on GPIO2 to provide a trigger for sampling oscilloscopes.
Reg 04’h, write 21’h
Power Save Mode
When a system does not need to transmit high speed data from the DS32EL0421 or DS32ELX0421, the power
consumption of the device can be managed as described in the POWER MANAGEMENT section on the
Functional Description page. The following recipe powers down many of the analog and digital blocks in the
serializer, but leaves the SMBus module operational. Please note that in order to resume normal operation the
recipe below will have to be unwritten.
Reg 01'h, write 10'h
Reg 26'h, write 40'h
Redundancy / Fail Over Configuration
DS32ELX0421 only. Implementing a redundancy system with the DS32ELX0421 can be done in several ways.
One method would be to program the redundancy or fail over logic into the host device or FPGA. The recipe
below will describe a different method, for which a DS32ELX0421 will communicate to two different DS32EL0124
deserializers. The recipe below will configure the DS32ELX0421 serializer to automatically switch to the alternate
output when the current high speed link fails.
Configure all device with Remote Sense enabled either by pin or register control. Pull TxOUT1_EN pin high
reg 2F'h, write 2D'h
Reg 2F'h, write 28'h
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
Submit Documentation Feedback
25
DS32EL0421, DS32ELX0421
SNLS282F – MAY 2008 – REVISED APRIL 2013
www.ti.com
REVISION HISTORY
Changes from Revision E (April 2013) to Revision F
•
26
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 25
Submit Documentation Feedback
Copyright © 2008–2013, Texas Instruments Incorporated
Product Folder Links: DS32EL0421 DS32ELX0421
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
DS32EL0421SQ/NOPB
ACTIVE
WQFN
RHS
48
1000
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 85
32EL0421
DS32EL0421SQE/NOPB
ACTIVE
WQFN
RHS
48
250
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 85
32EL0421
DS32EL0421SQX/NOPB
ACTIVE
WQFN
RHS
48
2500
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 85
32EL0421
DS32ELX0421SQE/NOPB
ACTIVE
WQFN
RHS
48
250
RoHS & Green
SN
Level-3-260C-168 HR
-40 to 85
32ELX0421
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
