78Q2120C
10/100BASE-TX
Transceiver
DATA SHEET
January 2009
DESCRIPTION
FEATURES
The 78Q2120C is a 10BASE-T/100BASE-TX Fast
Ethernet transceiver. It includes integrated MII,
ENDECs, scrambler/descrambler, dual-speed clock
recovery, and full-featured auto-negotiation function.
The transmitter includes an on-chip pulse-shaper and
a low-power line driver. The receiver has an adaptive
equalizer and a baseline restoration circuit required
for accurate clock and data recovery. The transceiver
interfaces to Category-5 unshielded twisted pair (Cat5 UTP) cabling for 100BASE-TX/10BASE-T and
Category-3 unshielded twisted pair for 10BASE-T.
Connection to the line media is via 1:1 isolation
transformers. No external filter is required. Interface
to the MAC is accomplished through an IEEE-802.3
compliant Media Independent Interface (MII). The
product is fabricated in an advanced CMOS process
for high performance and low power operation.
•
10BASE-T/100BASE-TX IEEE-802.3 compliant
TX and RX functions requiring a dual 1:1
isolation transformer interface to the line
•
Integrated MII, 10BASE-T/100BASE-TX ENDEC,
100BASE-TX scrambler/descrambler, and fullfeatured auto-negotiation function
•
Full duplex operation capable
•
PCS Bypass supports 5-bit symbol interface
•
Register-programmable transmit amplitude
•
Dual speed digital clock recovery
•
Automatic polarity correction during autonegotiation and 10BASE-T signal reception
•
Power-saving and power-down
including transmitter disable
•
LED indicators: LINK, TX, RX, COL, 100, 10,
FDX
•
User programmable Interrupt pin
•
64-Pin TQFP (JEDEC LQFP) package
•
Single 3.3 V ± 0.3V Supply
modes
BLOCK DIAGRAM
100M
4B/5B Encoder,
Scrambler,
Parallel/Serial
NRZ/NRZI
MLT3 Encoder
TXOP/N
RX_CLK
TX_CLK
RXD[3:0]
MII
Registers
&
Interface
Logic
Pulse
Pulse Shaper
Shaper
and Filter
TX CLK GEN
10M
MDI
Parallel/Serial,
Manchester
Manchester Encoder
Encoder
TXD[3:0]
Manchester Decoder,
Parallel/Serial
Serial/Parallel
Descrambler,
5B/4B Decoder
RXIP/N
Carrier Sense,
Collision Detect
Detect
Collision
Auto
Negotiation
10M
CLK
Recovery
Clock
Clock Reference
Reference
100M
Adaptive EQ,
Baseline Wander Correct,
MLT3
MLT3 Decode,
Decode, NRZI/NRZ
NRZI/NRZ
LEDs
PS
VCC
Page: 1 of 35
GND
CKIN
25MHz
LEDL
LEDBTX
LEDTX LEDCOL
LEDBT
LEDFX
LEDRX
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
•
Chip Power-Down
mode of operation, a 25MHz crystal should be
connected between the XTLP and XTLN pins.
Alternatively, an external 25MHz clock signal can be
connected to the CKIN pin. The chip senses activity
on the CKIN pin, and will automatically configure itself
to use the external clock. In this mode of operation, a
crystal is not required and the XTLP and XTLN pins
should be left floating or connected together.
•
Receive Power Management
•
Transmit Clock Generation
Transmit High Impedance Mode
FUNCTIONAL DESCRIPTION
GENERAL
Power Management
The 78Q2120C has three power saving modes:
Chip power-down is activated by setting the PWRDN
bit in MII register MR0.11 or pulling high the PWRDN
pin. When the chip is in the power-down mode, all
on-chip circuitry is shut off, and the device
consumes minimum power. While in the powerdown state, the 78Q2120C still responds to
management transactions.
Receive power management (RXCC mode) is
activated by setting the RXCC bit in MII register
MR16.0. In this mode of operation, the adaptive
equalizer, the clock recovery phase lock loop (PLL),
and all other receive circuitry will be powered down
when no valid MLT-3 signal is present at the UTP
receive line interface. As soon as a valid signal is
detected, all circuits will automatically be powered
up to resume normal operation. During this mode of
operation, RX_CLK will be inactive when there is no
data being received. Note that the RXCC mode is
not supported during 10BASE-T operation.
The transmitter uses an on-chip frequency
synthesizer to generate the transmit clock. In
100BASE-TX operation, the synthesizer multiplies the
reference clock by 5 to obtain the internal 125MHz
serial transmit clock.
In 10BASE-T mode, it
generates an internal 20MHz transmit clock by
multiplying the 25MHz reference clock by 4/5. The
synthesizer references either the local 25 MHz crystal
oscillator, or the externally applied clock, depending
on the selected mode of operation.
Receive Signal Qualification
Transmit high impedance mode is activated by
setting the TXHIM bit in MII register MR16.12. In this
mode of operation, the transmit UTP drivers are in a
high impedance state and TX_CLK is tri-stated. A
weak internal pull-up is enabled on TX_CLK. The
receive circuitry remains fully operational. The
default state of MR16.12 is a logic low for disabling
the transmit high impedance mode. The transmitter
is fully functional when MR16.12 is cleared.
The integrated signal qualifier has separate squelch
and unsquelch thresholds. It also includes a built-in
timer to ensure fast and accurate signal detection and
line noise rejection. Upon detection of two or more
valid 10BASE-T or 100BASE-TX pulses on the line
receive port, signal detect is indicated. The signal
detect threshold is then lowered by about 40%. All
adaptive circuits are released from their initial states
and allowed to lock onto the incoming data. In
100BASE-TX operation, signal detect is de-asserted
when no signal is presented for a period of about
1.2us. In 10BASE-T operation, signal detect is deasserted whenever no Manchester data is received. In
either case, the signal detect threshold will return to the
squelched level whenever the signal detect indication
is de-asserted. Signal detect is also used to control the
operation of the clock/data recovery circuit to assure
fast acquisition.
Analog Biasing and Supply Regulation
Receive Clock Recovery
The 78Q2120C requires no external component to
generate on-chip bias voltages and currents. High
accuracy is maintained through a closed-loop
trimmed biasing network.
In 100BASE-TX mode, the 125MHz receive clock is
extracted using a digital DLL-based loop. When no
receive signal is present, the CDR is directed to lock
onto the 125MHz transmit serial clock. When signal
detect is asserted, the CDR will use the received MLT3 signal as the clock reference. The recovered clock is
used to re-time the data signal and for conversion of
the data to NRZ format.
On-chip digital logic runs off an internal voltage
regulator. Hence only a single Vcc supply is
required to power-up the device. The on-chip
regulator is not affected by the power-down mode.
Clock Selection
The 78Q2120C will use the on-chip crystal oscillator
as the clock source if the CKIN pin is tied low. In this
Page: 2 of 35
In 10BASE-T mode, the 10MHz receive clock is
recovered digitally from the Manchester data using a
DLL locked to the reference clock.
When
Manchester-coded preambles are detected, the
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
CDR immediately re-aligns the phase of the clock to
synchronize with the incoming data. Hence clock
acquisition is fast and immediate.
100BASE-TX OPERATION
100BASE-TX Transmit
The 78Q2120C contains all of the necessary
circuitry to convert the transmit MII signaling from a
MAC to an IEEE-802.3 compliant data-stream
driving Cat-5 UTP cabling.
The internal PCS
interface maps 4 bit nibbles from the MII to 5 bit
code groups as defined in Table 24-1 of IEEE-802.3.
These 5 bit code groups are then scrambled and
converted to a serial stream before being sent to the
MLT-3 pulse shaping circuitry and line driver. The
pulse-shaper uses current modulation to produce
the desired output waveform. Controlled rise/fall
time in the MLT-3 signal is achieved using an
accurately controlled voltage ramp generator. The
line driver requires an external 1:1 isolation
transformer to interface with the line media. The
center-tap of the primary side of the transformer
must be connected to the Vcc supply.
100BASE-TX Receive
The 78Q2120C receives a 125MBaud MLT-3 signal
through a 1:1 transformer. The signal then goes
through a combination of adaptive offset adjustment
(baseline wander correction) and adaptive
equalization. The effect of these circuits is to sense
the amount of dispersion and attenuation caused by
the cable and transformer, and restore the received
pulses to logic levels. The amount of gain and
equalization applied to the pulses varies with the
detected attenuation and dispersion and, therefore,
with the length of the cable. The 78Q2120C can
compensate for cable loss of up to 10dB at 16 MHz.
This loss is represented as test-chan 5 in Annex A of
the ANSI X3.263:199X specification. The equalized
MLT-3 data signal is bi-directionally sliced and the
resulting NRZI bit-stream is presented to the CDR
where it is re-timed and decoded to NRZ format.
The re-timed serial data passes through a serial to
parallel converter, then is descrambled and aligned
into 5 bit code groups. The receive PCS interface
maps these code groups to 4 bit data for the MII as
outlined in Table 24-1 in Clause 24 of IEEE-802.3.
PCS Bypass Mode (Auto-negotiate must be off)
The PCS Bypass mode is entered by pulling PCSBP
high or by setting register bit MR 16.1. In this mode
the 78Q2120C accepts scrambled 5 bit code words
at the TX_ER and TXD[3:0] pins, TX_ER being the
Page: 3 of 35
MSB of the data input. The 5 bit code groups are
converted to MLT-3 signal for transmission.
The received MLT-3 signal is converted to 5 bit NRZ
code groups and output from the RX_ER and
RXD[3:0] pins, RX_ER being the MSB of the data
output. The RX_DV and TX_EN pins are unused in
PCS Bypass mode.
10BASE-T OPERATION
10BASE-T Transmit
The 78Q2120C takes 4-bit parallel NRZ data via the
MII interface and passes it through a parallel to
serial converter. The data is then passed through a
Manchester encoder, pre-emphasis pulse-shaper,
media filter, and finally to the twisted-pair line driver.
The pulse-shaper and filter ensure the output
waveforms meet the voltage template and spectral
content requirements detailed in Clause 14 of IEEE802.3. Interface to the twisted-pair media is through
a center-tapped 1:1 transformer.
No external
filtering is required. During auto-negotiation and
10BASE-T idle periods, link pulses are transmitted.
The 78Q2120C employs an onboard timer to
prevent the MAC from capturing a network through
excessively long transmissions. When this timer
expires, the chip enters the jabber state and
transmission is halted. The jabber state is exited
after the MII goes idle for 500±250ms.
10BASE-T Receive
The 78Q2120C receives Manchester-encoded
10BASE-T data through the twisted pair inputs and
re-establishes logic levels through a slicer with a
smart squelch function. The slicer automatically
adjusts its level after detection of valid data with the
appropriate levels. Data is passed on to the CDR
where the clock is recovered, and the data is retimed and decoded. From there, data enters the
serial-to-parallel converter for transmission to the
MAC via the Media Independent Interface. Interface
to the twisted-pair media is through an external 1:1
transformer. Polarity information is detected and
corrected within internal circuitry.
Polarity Correction
The 78Q2120C is capable of either automatic or manual
polarity reversal for 10BASE-T and auto-negotiation
functions. Register bits MR16.5 and MR16.4 control this
feature. The default is automatic mode where MR16.5
is low and MR16.4 indicates if the detection circuitry
has inverted the input signal. To enter manual
mode, MR16.5 should be set high and MR16.4 will
then control the signal polarity.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
SQE TEST
The 78Q2120C supports the Signal Quality Error
(SQE) function detailed in IEEE-802.3.
At an
interval of 1µs after each negative transition of the
TXEN pin in 10BASE-T mode, the COL pin will go
high for a period of 1µs. SQE is not signaled during
transmission after collision is detected. SQE is
automatically disabled when repeater mode is
enabled. This function can be disabled through
register bit MR16.11.
Natural Loopback
When enabled, whenever the 78Q2120C is
transmitting and not receiving on the twisted pair
media (10BASE-T Half Duplex mode), data on the
TXD[3:0] pins is looped back onto the RXD[3:0] pins.
During a collision, data from the RXI pins is routed to
the RXD[3:0] pins. The natural loopback function is
enabled through register bit MR16.10.
Repeater Mode
When the RPTR pin is high or register bit MR16.15
is set, the 78Q2120C is placed in repeater mode. In
this mode, full duplex operation is prohibited, CRS
responds only to receive activity and, in 10BASE-T
mode, the SQE test function is disabled.
will look for either 10BASE-T idle, 100BASE-TX idle,
or fast link pulses from its link partner. If either idle
pattern is detected, the 78Q2120C configures itself
in half-duplex mode at the appropriate speed. If it
detects fast link pulses, it decodes and analyzes the
link code transmitted by the link partner. When
three identical link code words are received (ignoring
the acknowledge bit) the link code word is stored in
register MR5. Upon receiving three more identical
link code words, with the acknowledge bit set, the
78Q2120C configures itself to the highest priority
technology common to the two link partners. The
technology priorities are, in descending order:
100BASE-TX, Full Duplex
100BASE-TX, Half Duplex
10BASE-T, Full Duplex
10BASE-T, Half Duplex
Once auto-negotiation is complete, register bits
MR18.11:10 will reflect the actual speed and duplex
that was chosen.
If auto-negotiation fails to establish a link for any
reason, register bit MR18.12 will reflect this and auto
negotiation will restart from the beginning. Writing a
‘1’ to bit MR0.9(RANEG) will also cause autonegotiation to restart.
MEDIA INDEPENDENT INTERFACE
AUTO-NEGOTIATION
MII Transmit and Receive Operation
The 78Q2120C supports the auto-negotiation
functions of Clause 28 of IEEE-802.3 for 10/100
Mbps operation over copper wiring. This function
can be enabled via a pin selection or register
settings. If the ANEGA pin is tied high, the autonegotiation function defaults to ON and bit MR0.12
(ANEGEN) is high after reset. Software can disable
the auto-negotiation function by writing to bit
MR0.12. If the ANEGA pin is tied low, the function
defaults to OFF and bit MR0.12 is set low after reset
and cannot be written to.
The MII interface on the 78Q2120C provides
independent transmit and receive paths for both
10Mb/s and 100Mb/s data rates as described in
Clause 22 of the IEEE-802.3 standard.
The contents of register MR4 are sent to the
78Q2120C’s link partner during auto-negotiation
using fast link pulse coding. Bits MR4.8:5 reflect the
state of the TECH[2:0] pins after reset. If TECH[2:0]
= ‘111’, then all 4 bits are high. If TECH[2:0] = ‘001’,
then only bit 5 is high. After reset, software can
change any of these bits from a ‘1’ to a ‘0’; but not
from a ‘0’ to a ‘1’. Therefore, a technology permitted
by the setting of the TECH pins can be disabled, but
cannot be enabled through register selection.
With auto-negotiation enabled, the 78Q2120C will
start sending fast link pulses at power on, loss of link
or upon a command to restart. At the same time, it
Page: 4 of 35
The transmit clock, TX_CLK, provides the timing
reference for the transfer of TX_EN, TXD[3:0], and
TX_ER signals from the MAC to the 78Q2120C.
TXD[3:0] is captured on the rising edge of TX_CLK
when TX_EN is asserted. TX_ER is also captured
on the rising edge of TX_CLK and is asserted by the
MAC to request that an error code group is to be
transmitted. The assertion of TX_ER is ignored
when the 78Q2120C is operating in 10BASE-T
mode.
The receive clock, RX_CLK, provides the timing
reference to transfer RX_DV, RXD[3:0], and RX_ER
signals from the 78Q2120C to the MAC. RX_DV
transitions synchronously with respect to RX_CLK
and is asserted when the 78Q2120C is presenting
valid data on RXD[3:0]. RX_ER is asserted and is
synchronous to RX_CLK when a code group
violation has been detected in the current receive
packet.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
Station Management Interface
The station management interface consists of
circuitry which implements the serial protocol as
described in Clause 22.2.4.5 of IEEE-802.3. A 16bit shift register receives serial data applied to the
MDIO pin at the rising-edge of the MDC clock signal.
Once the preamble is received, the station
management control logic looks for the start-offrame sequence and a read or write op-code,
followed by the PHYAD and REGAD fields. For a
read operation, the MDIO port becomes enabled as
an output and the register data is loaded into a shift
register for transmission. The 78Q2120C can work
with a one bit preamble rather than the 32 bits
prescribed by IEEE-802.3. This allows for faster
programming of the registers. If a register does not
exist at an address indicated by the REGAD field or
if the PHYAD field does not match the 78Q2120C
PHYAD indicated by the PHYAD pins, a read of the
MDIO port will return all ones. For a write operation,
the data is shifted in and loaded into the appropriate
register after the sixteenth data bit has been
received.
When the PHYAD field is all zeros, the Station
Management Entity (STA) is requesting a broadcast
data transaction.
All PHYs sharing the same
Management Interface must respond to this
broadcast request. The 78Q2120C will respond to
the broadcast data transaction.
ADDITIONAL FEATURES
78Q2120C. There is an LED pin that indicates the
link is up (LEDL), others that indicate the 78Q2120C
is either transmitting (LEDTX) or receiving (LEDRX),
one that signals a collision event (LEDCOL), two
more that reflect the data rate (LEDBTX and LEDBT),
and one that reflects full duplex mode of operation
(LEDFDX).
Interrupt Pin
The 78Q2120C has an Interrupt pin (INTR) that is
asserted whenever any of the eight interrupt bits of
MR17.7:0 are set. These interrupt bits can be
disabled via the MR17.15:8 Interrupt Enable bits.
The Interrupt Polarity bit, MR16.14, controls the
active level of the INTR pin. When the INTR pin is
not asserted, this pin is held in a high impedance
state. An external pull-up or pull-down resistor may
be required for use with the INTR pin.
APPLICATIONS REQUIREMENTS
RXIP/N Termination Connection
The input circuitry of the TERIDIAN 78Q2120C has
changed for continuing performance improvements.
Device revision C09 requires that the RXIP/N
termination resistors and transformer center tap
connections be directly connected to VCC for proper
receiver operation.
Refer to Figure 1: Typical
Applications Circuit for the schematic showing the
required RXIP/N termination resistors and
transformer center tap connections to VCC for
revision 78Q2120C.
LED Indicators
There are seven LED pins that can be used to
indicate various states of operation of the
Page: 5 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
PIN DESCRIPTION
LEGEND
TYPE
A
DESCRIPTION
TYPE
Analog Pin
CI
DESCRIPTION
TTL-level Input (5V compatible)
CIU
TTL-level Input w/ Pull-up (5V compatible)
CIO
TTL-compatible Bi-directional Pin (5V compatible)
CID
TTL-level Input w/ Pull-down
COZ
Tristate-able CMOS output
(5V compatible)
CIS
TTL-level Input w/ Schmitt Trigger
G
Ground
S
Supply
(5V compatible)
CO
CMOS Output
MII (MEDIA INDEPENDENT INTERFACE)
NAME
PIN
TYPE
DESCRIPTION
TX_CLK
27
COZ
TX_EN
28
CI
32-29
CI
TX_ER
26
CI
CRS
34
COZ
COL
33
COZ
RX_CLK
24
COZ
RX_DV
23
COZ
19-22
COZ
TRANSMIT CLOCK: TX_CLK is a continuous clock, which provides a timing
reference for the TX_EN, TX_ER and TXD[3:0] signals from the MAC. The
clock frequency is 25MHz in 100BASE-TX mode and 2.5MHz in 10BASE-T
mode. This pin is tristated in the isolate mode and the TXHIM mode.
TRANSMIT ENABLE: TX_EN is asserted by the MAC to indicate that valid
data for transmission is present on the TXD[3:0] pins.
TRANSMIT DATA: TXD[3:0] receives data from the MAC for transmission on
a nibble basis. This data is captured on the rising edge of TX_CLK when
TX_EN is high.
TRANSMIT ERROR: TX_ER is asserted high by the MAC to request that an
error code-group be transmitted when TX_EN is high. In PCS bypass mode
this pin becomes the MSB of the transmit 5-bit code group.
CARRIER SENSE: When the 78Q2120C is not in repeater mode, CRS is high
whenever a non-idle condition exists on either the transmitter or the receiver.
In repeater mode, CRS is only active when a non-idle condition exists on the
receiver. This pin is tristated in the isolate mode.
COLLISION: COL is asserted high when a collision has been detected on the
media. In 10BASE-T mode, COL is also used for the SQE test function. This
pin is tristated in the isolate mode. During half duplex operation, the rising
edge of COL will occasionally occur upon the rising edge of TX_CLK.
RECEIVE CLOCK: RX_CLK is a continuous clock, which provides a timing
reference to the MAC for the RX_DV, RX_ER and RXD[3:0] signals. The
clock frequency is 25MHz in 100BASE-TX mode, and 2.5MHz in 10BASE-T
mode. To reduce power consumption in 100BASE-TX mode, the 78Q2120C
provides an optional mode, enabled through MR16.0, in which RX_CLK is
held inactive (low) when no receive data is detected. This pin is tristated in
the isolate mode.
RECEIVE DATA VALID: RX_DV is asserted high to indicate that valid data is
present on the RXD[3:0] pins. In 100BASE-TX mode, it transitions high with
the first nibble of the preamble and is pulled low when the last data nibble has
been received. In 10BASE-T mode, it transitions high when the start-of-frame
delimiter (SFD) is detected. This pin is tristated in the isolate mode.
RECEIVE DATA: Received data is provided to the MAC via RXD[3:0]. These
pins are tristated in the isolate mode.
TXD[3:0]
RXD[3:0]
Page: 6 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MII (continued)
NAME
PIN
TYPE
DESCRIPTION
RX_ER
25
COZ
RECEIVE ERROR: RX_ER is asserted high when an error is detected during a
frame reception. In PCS bypass mode, this pin becomes the MSB of the receive
5-bit code group. This pin is tristated in the isolate mode.
MDC
18
CIS
MANAGEMENT DATA CLOCK: MDC is the clock used for transferring data
via the MDIO pin.
MDIO
17
CIO
MANAGEMENT DATA INPUT/OUTPUT: MDIO is a bi-directional port used to
access management registers within the 78Q2120C. This pin requires an
external pull-up resistor as specified in IEEE-802.3.
PIN
TYPE
12-16
CI
PHY ADDRESS
NAME
PHYAD[4:0]
DESCRIPTION
PHY ADDRESS: Allows 31 configurable PHY addresses. The 78Q2120C
always responds to broadcast data transactions via the MII interface when the
PHYAD bits are all zero, independent of the logic levels of the PHYAD pins.
PMA (PHYSICAL MEDIA ATTACHMENT) INTERFACE
NAME
PIN
TYPE
PCSBP
64
CID
DESCRIPTION
PCS BYPASS: When high, the 100BASE-TX PCS is bypassed, as well as
the scrambler and descrambler functions. Scrambled 5-bit code groups for
transmission are applied to the TX_ER, TXD[3:0] pins and received on the
RX_ER, RXD[3:0] pins. The RX_DV and TX_EN signals are not valid in this
mode. PCS bypass mode is only valid when 100BASE-TX is enabled and
auto-negotiation is disabled. This mode can also be entered by setting
MR16.1.
CONTROL AND STATUS
NAME
RST
PWRDN
Page: 7 of 35
PIN
TYPE
6
CIU
7
CID
DESCRIPTION
ACTIVE-LOW RESET: When pulled low, the pin resets the chip. The reset
pulse must be long enough to guarantee stabilization of the supply voltage
and startup of the oscillator. Refer to the Electrical Specifications for the
reset pulse requirements. There are 2 other ways to reset the chip:
i)
through the internal power-on-reset (activated when the chip is
being powered up)
ii)
through the MII register bit (MR0.15)
POWER-DOWN: The 78Q2120C may be placed in a low power consumption
state by setting this signal to logic high. While in the power-down state, the
78Q2120C still responds to management transactions. This power-down
state can also be activated using the PWRDN bit in the MII register (MR0.11).
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
CONTROL AND STATUS (CONTINUED)
NAME
PIN
TYPE
ISO
2
CI
ISOLATE: When set to logic one, the 78Q2120C will present a high
impedance on its MII output pins. This allows for multiple chips to be
attached to the same MII interface. When the 78Q2120C is isolated, it still
responds to management transactions. This high impedance state can also
be achieved using the ISO bit in the MII register (MR0.10).
ISODEF
1
CI
ISOLATE DEFAULT: This pin determines the power-up/reset default of the
ISO bit (MR0.10). If it is connected to VCC, the ISO bit will have a default
value of ‘1’. Otherwise, the bit defaults to ‘0’. When this signal is tied to VCC,
it allows multiple chips to be connected to the same MII interface.
ANEGA
47
CI
AUTO-NEGOTIATION ABILITY: Connect to logic high to enable the autonegotiation function. When connected to logic low, the auto-negotiation logic
is disabled and manual technology selection is done through TECH[2:0] pins.
This pin is reflected as the ANEGA bit in MR1.3.
44-46
CI
TECHNOLOGY ABILITY/SELECT: TECH[2:0] sets the technology ability of
the chip which is reflected in MR0.13,8, MR1.14:11 and MR4.12:5.
TECH[2:0]
DESCRIPTION
TECH[2:0]
111
Both 10BASE-T and 100BASE-TX, and
Both half and full duplex
None
10BASE-T, half duplex
100BASE-TX, half duplex
Both 10BASE-T and 100BASE-TX, half duplex only
None
10BASE-T Both half and full duplex
100BASE-TX Both half and full duplex
000
001
010
011
100
101
110
RPTR
50
CID
Technology Ability
REPEATER MODE: When pulled high, this pin puts the chip into repeater
mode. In this mode, full duplex is prohibited, CRS responds to receive activity
only. In 10BASE-T mode, the SQE test function is disabled. This mode can
also be enabled by setting bit MR16.15
MDI (MEDIA DEPENDENT INTERFACE)
NAME
PIN
TYPE
TXOP/N
61,62
A
TRANSMIT OUTPUT POSITIVE/NEGATIVE: Transmitter differential outputs
for both 10BASE-T and 100BASE-TX operation.
RXIP/N
52,51
A
RECEIVE INPUT POSITIVE/NEGATIVE: Receiver differential inputs for
both 10BASE-T and 100BASE-TX operation.
Page: 8 of 35
DESCRIPTION
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
LED INDICATORS
The LED pins use standard logic drivers. They output a logic low when the LED is meant to be on and a logic
high when it is meant to be off. The LED should be connected in series with a resistor between the output pin and
the power supply.
NAME
PIN
TYPE
DESCRIPTION
LEDL
40
CO
LED LINK: ON for link up.
LEDTX
39
CO
LED TRANSMIT: ON when there is a transmission (normally OFF).
LEDRX
38
CO
LED RECEIVE: ON when there is a reception (normally OFF).
LEDCOL
37
CO
LED COLLISION: In half duplex mode, this is a collision indicator and turns ON
when a collision occurs. In full duplex mode, this LED is held OFF.
LEDBTX
36
CO
LED 100BASE-TX: ON for 100BASE-TX connection and OFF for other
connections. LEDBTX is OFF during auto-negotiation.
LEDBT
48
CO
LED 10BASE-T: ON for 10BASE-T connection and OFF for other
connections. LEDBT is OFF during auto-negotiation.
LEDFDX
49
CO
LED FULL DUPLEX: ON when in full duplex mode and OFF when in half
duplex mode.
OSCILLATOR/CLOCK
NAME
CKIN
XTLP/N
PIN
TYPE
DESCRIPTION
4
CIS
CLOCK INPUT: Connects to a 25 MHz TTL compatible clock source. This
pin should be held low when XTLP and XTLN are being used as the 25 MHz
clock source.
59,58
A
CRYSTAL PINS: Should be connected to a 25 MHz crystal. When CKIN is
being used as the 25 MHz clock source, these pins should be left floating or
connected together.
MISCELLANEOUS PIN
NAME
INTR
NC
PIN
TYPE
DESCRIPTION
35
COZ
INTERRUPT PIN: This pin is used to signal an interrupt to the media access
controller. The pin is held in the high impedance state when an interrupt is
not indicated. The pin will be forced high or low to signal an interrupt
depending upon the value of the INPOL bit (MR16.14). The events which
trigger an interrupt can be programmed via the Interrupt Control Register
located at address MR17.
54,56
--
No Connect. Do not connect to ground or supply.
POWER SUPPLY AND GROUND
NAME
PIN
TYPE
DESCRIPTION
VCC
8,11,41,
43,57,63
S
3.3V SUPPLY
GND
3,5,9,10,
42,53,55,60
G
GROUND
Page: 9 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
REGISTER DESCRIPTION
The 78Q2120C implements 11 16-bit registers, which are accessible via the MDIO and MDC pins. The supported
registers are shown below in the following table. Attempts to read unsupported registers will be ignored and the
MDIO pin will not be enabled as an output, as per the IEEE 802.3 specification. All of the registers except those
which are unique to the 78Q2120C, will respond to the broadcast PHYAD value of ‘00000’. The registers specific
to the 78Q2120C occupy address space MR16-22.
ADDRESS
0
1
2
3
4
5
6
7
8-14
15
16
17
18
19
20-22
SYMBOL
MR0
MR1
MR2
MR3
MR4
MR5
MR6
MR7
MR8-14
MR15
MR16
MR17
MR18
MR19
MR20-MR22
NAME
Control
Status
PHY Identifier 1
PHY Identifier 2
Auto-Negotiation Advertisement
Auto-Negotiation Link Partner Ability
Auto-Negotiation Expansion
Not Implemented
Reserved
Not Implemented
Vendor Specific
Interrupt Control/Status Register
Diagnostic Register
Transceiver Control
Reserved
DEFAULT (HEX)
(3100)
(7809)
000E
70C9
(01E1)
0000
0000
0000
0000
0000
(0140)
0000
0000
4XXX
0000
Legend:
TYPE
R
SC
0/1
Page: 10 of 35
DESCRIPTION
Readable by management.
Writeable by management. Self
Clearing.
Default value upon power up or
reset.
TYPE DESCRIPTION
W
Writeable by management.
RC
Readable by management.
Cleared upon a read operation.
(0/1) Default value dependent on pin
settings. The value in bracket
indicates typical case.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR0: Control Register
BIT
0.15
SYMBOL
RESET
TYPE
R/SC
0.14
LOOPBK
R/W
0
Loopback: When this bit is set to ‘1’, no transmission of data on the
network medium occurs and any receive data on the network
medium is ignored. The loopback signal path will encompass most
of the digital circuitry.
0.13
SPEEDSL
R/W
(1)
Speed Selection: This bit determines the speed of operation of the
78Q2120C. Setting this bit to ‘1’ indicates 100Base-TX operation
and a ‘0’ indicates 10Base-T mode. This bit will default to a ‘1’ upon
reset. If the TECH[2:0] pins are all logic zero and auto-negotiation is
not enabled, this bit will be writeable. If auto-negotiation is not
enabled and the TECH[2:0] pins are set to indicate that only
10Base-T is supported, this bit will be forced to logic zero and will
not be writeable. If auto-negotiation is not enabled and the
TECH[2:0] pins are set to indicate that only 100Base-TX is
supported, this bit will be forced to logic one and will not be
writeable. When auto-negotiation is enabled, this bit will not be
writeable and will have no effect on the 78Q2120C. If the
TECH[2:0] pins are brought to zero from another value, this bit will
retain its original value until it is overwritten.
0.12
ANEGEN
R/W
(1)
Auto-Negotiation Enable: Setting this bit to ‘1’ enables the autonegotiation process. This bit can only be set if the ANEGA pin is a
logic one and will default to ‘1’ upon reset. If this bit is cleared to ‘0’,
manual speed and duplex mode selection is accomplished through
bits 0.13 (SPEEDSL) and 0.8 (DUPLEX) of the Control Register or
the TECH[2:0] pins according to the table shown in the section
describing the TECH[2:0] pins. If the ANEGA pin is brought from ‘0’
to ‘1’ and reset is not asserted, this bit will remain at ‘0’ until a ‘1’ is
written.
0.11
PWRDN
R/W
0
Power-Down:
The device may be placed in a low power
consumption state by setting this bit to ‘1’. While in the power-down
state, the device will still respond to management transactions.
Setting the PWRDN pin high also activates the power-down state.
0.10
ISO
R/W
(0)
Isolate: When set to ‘1’, the device presents a high-impedance on
its MII output pins. This allows for multiple PHY’s to be attached to
the same MII interface. When the device is isolated, it still responds
to management transactions. The default value of this bit depends
on the ISODEF pin. When ISODEF pin is tied high, the ISO bit
defaults to high. Otherwise, it defaults to low. The Isolate mode can
also be activated using the ISO pin.
0.9
RANEG
R/SC
0
Restart Auto-Negotiation: Normally, the Auto-Negotiation process is
started at power up. The process can be restarted by setting this bit
to ‘1’. This bit is self-clearing.
Page: 11 of 35
DEFAULT DESCRIPTION
0
Reset: Setting this bit to ‘1’ resets the device and sets all registers
to their default states. This bit is self-clearing.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR0: Control Register (continued)
BIT
0.8
SYMBOL
DUPLEX
TYPE
R/W
DEFAULT DESCRIPTION
(1)
Duplex Mode: This bit determines whether the device supports fullduplex or half-duplex. A ‘1’ indicates full-duplex operation and a ‘0’
indicates half-duplex. This bit will default to ‘0’ upon reset and will
be writeable if the TECH[2:0] pins are all logic zero and autonegotiation is not enabled. If auto-negotiation is not enabled and
the TECH[2:0] pins are set to indicate that only full-duplex is
supported, this bit will be forced to ‘1’ and will not be writeable. If
auto-negotiation is not enabled and the TECH[2:0] pins are set to
indicate that only half-duplex is supported, this bit will be forced to
‘0’ and will not be writeable. When auto-negotiation is enabled, this
bit will not be writeable and will have no effect on the device. If the
TECH[2:0] pins are brought to zero from another value, this bit will
retain its original value until it is overwritten.
0.7
COLT
R/W
0
Collision Test: When this bit is set to ‘1’, the device will assert the
COL signal in response to the assertion of the TX_EN signal.
Collision test is disabled if the PCSBP pin is high. Collision test can
be activated regardless of the duplex mode of operation.
0.6:0
RSVD
R
0
Reserved
MR1: Status Register
Bits 1.15 through 1.11 reflect the ability of the 78Q2120C as configured by the TECH[2:0] pins. They do not
reflect any ability changes made via the MII Management interface to bits 0.13 (SPEEDSL) , 0.12 (ANEGEN) and
0.8 (DUPLEX).
BIT
1.15
SYMBOL
100T4
TYPE
R
1.14
100X_F
R
DEFAULT DESCRIPTION
0
100BASE-T4 Ability: Reads ‘0’ to indicate the 78Q2120C does not
support 100Base-T4 mode.
(1)
100BASE-TX Full Duplex Ability:
0 : Not able
1 : Able
1.13
100X_H
R
(1)
100BASE-TX Half Duplex Ability:
0 : Not able
1 : Able
1.12
10T_F
R
(1)
10BASE-T Full Duplex Ability:
0 : Not able
1 : Able
1.11
10T_H
R
(1)
10BASE-T Half Duplex Ability:
0 : Not able
1 : Able
1.10
100T2_F
Page: 12 of 35
R
0
100BASE-T2 Full Duplex Ability:
Reads ‘0’ to indicate the
78Q2120C does not support 100Base-T2 full duplex mode.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR1: Status Register
BIT
1.9
SYMBOL
100T2_H
TYPE
R
DEFAULT DESCRIPTION
0
100BASE-T2 Half Duplex Ability:
Reads ‘0’ to indicate the
78Q2120C does not support 100Base-T2 full duplex mode.
1.8
EXTS
R
0
Extended Status Information Availability: Reads ‘0’ to indicate the
78Q2120C does not support Extended Status information on MR15.
1.7
RSVD
R
0
Reserved
1.6
MFPS
R
0
Management Frame Preamble Suppression Support:
A “0”
indicates that the 78Q2120C can read management frames with a
preamble.
1.5
ANEGC
R
0
Auto-Negotiation Complete: A logic one indicates that the AutoNegotiation process has been completed, and that the contents of
registers MR4,5,6 are valid.
1.4
RFAULT
RC
0
Remote Fault: A logic one indicates that a remote fault condition
has been detected and remains set until it is cleared. This bit can
only be cleared by reading this register (MR1) via the management
interface.
1.3
ANEGA
R
(1)
Auto-Negotiation Ability: When set, this bit indicates the device’s
ability to perform Auto-Negotiation. The value of this bit is
determined by the ANEGEN bit (MR0.12).
1.2
LINK
R
0
Link Status: A logic one indicates that a valid link has been
established. If the link status should transition from an OK status to
a NOT-OK status, this bit will become cleared and remains cleared
until it is read.
1.1
JAB
RC
0
Jabber Detect: In 10Base-T mode, this bit is set during a jabber
event. After a jabber event, the bit remains set until cleared by a
read operation.
1.0
EXTD
R
1
Extended Capability: Reads ’1’ to indicate the 78Q2120C provides
an extended register set (MR2 and beyond).
MR2: PHY Identifier Register 1
BIT
2.15:0
SYMBOL
OUI
[23:6]
TYPE
R
VALUE
000Eh
DESCRIPTION
Organizationally Unique Identifier: This value is 00-C0-39 for
TERIDIAN Semiconductor Corporation. This register contains the
first 16-bits of the identifier.
MR3: PHY Identifier Register 2
BIT
3.15:10
TYPE
R
VALUE
1Ch
3.9:4
SYMBOL
OUI
[5:0]
MN
R
0Ch
Model Number: The last 2 digits of the model number 78Q2120C are
encoded into the 6 bits.
3.3:0
RN
R
9h
Revision Number: The value ‘1001’ corresponds to the ninth revision
of the silicon.
Page: 13 of 35
DESCRIPTION
Organizationally Unique Identifier: Remaining 6 bits of the OUI.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR4: Auto-Negotiation Advertisement Register
BIT
4.15
SYMBOL
NP
4.14
RSVD
R
0
Reserved
4.13
RF
R/W
0
Remote Fault: Setting this bit to ‘1’ allows the device to indicate to
the link partner a Remote Fault Condition.
4.12:5
TAF
R/W
(0Fh)
Technology Ability Field: The default value of this field is dependent
upon the MR1.15:11 register bits. This field can be overwritten by
management to auto-negotiate to an alternate common technology.
Writing to this register has no effect until auto-negotiation is reinitiated.
4.12
A7
R
0
Reserved for future technology.
4.11
A6
R/W
0
Reserved
4.10
A5
R/W
0
Reserved.
4.9
A4
R
0
100BASE-T4:
operation.
4.8
A3
R/W
(1)
100BASE-TX Full Duplex: If the MR1.14 bit is ‘1’, this bit will be set
to ‘1’ upon reset and will be writeable. Otherwise, this bit cannot be
set to ‘1’ by the management.
4.7
A2
R/W
(1)
100BASE-TX: If the MR1.13 bit is ‘1’, this bit will be set to ‘1’ upon
reset and will be writeable. Otherwise, this bit cannot be set to ‘1’ by
the management.
4.6
A1
R/W
(1)
10BASE-T Full Duplex: If the MR1.12 bit is ‘1’, this bit will be set to
‘1’ upon reset and will be writeable. Otherwise, this bit cannot be set
to ‘1’ by the management.
4.5
A0
R/W
(1)
10BASE-T: If the MR1.11 bit is ‘1’, this bit will be set to ‘1’ upon reset
and will be writeable. Otherwise, this bit cannot be set to ‘1’ by the
management.
4.4:0
S4:0
R
01h
Selector Field: Hard coded with the value of ‘00001’ for IEEE 802.3.
Page: 14 of 35
TYPE DEFAULT DESCRIPTION
R
0
Next Page: Not supported. Reads logic zero.
The 78Q2120C does not support 100BASE-T4
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR5: Auto-Negotiation Link Partner Ability Register
BIT
5.15
SYMBOL
NP
TYPE DEFAULT DESCRIPTION
R
0
Next Page: When ‘1’ is read, it indicates the link partner wishes to
engage in Next Page exchange.
5.14
ACK
R
0
Acknowledge: When ‘1’ is read, it indicates the link partner has
successfully received at least 3 consecutive and consistent FLP
bursts.
5.13
RF
R
0
Remote Fault: When ‘1’ is read, it indicates the link partner has a
fault.
5.12:5
A7:0
R
0
Technology Ability Field: This field contains the technology ability of
the link partner. The bit definition is the same as MR4.12:5.
5.4:0
S4:0
R
00h
Selector Field: This field contains the type of message sent by the
link partner. For IEEE 802.3 compliant link partner, this field should
be ‘00001’.
MR6: Auto-Negotiation Expansion Register
BIT
6.15:5
SYMBOL
RSVD
6.4
PDF
RC
0
Parallel Detection Fault: When ‘1’ is read, it indicates that more than
one technology has been detected during link up. This bit is cleared
when read.
6.3
LPNPA
R
0
Link Partner Next Page Able: When ‘1’ is read, it indicates the link
partner supports the Next Page function.
6.2
NPA
R
0
Next Page Able: Reads ‘0’ since the 78Q2120C does not support
Next Page function.
6.1
PRX
RC
0
Page Received: Reads ‘1’ when a new link code word has been
received into the Auto-Negotiation Link Partner Ability Register. This
bit is cleared upon read.
6.0
LPANEG
A
R
0
Link Partner Auto-Negotiation Able: When ‘1’ is read, it indicates the
link partner is able to participate in the Auto-Negotiation function.
Page: 15 of 35
TYPE DEFAULT DESCRIPTION
R
0
Reserved
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR16: Vendor Specific Register
BIT
16.15
SYMBOL
RPTR
16.14
INPOL
R/W
0
When this bit is ‘0’, the INTR pin is forced low to signal an interrupt.
Setting this bit to ‘1’ causes the INTR pin to be forced high to signal
an interrupt.
16.13
RSVD
R
0
Reserved
16.12
TXHIM
R/W
0
Transmitter High-Impedance Mode: When set, the TXOP/TXON
transmit pins and the TX_CLK pin are put into a high-impedance
state. The receive circuitry remains fully functional.
16.11
SQEI
R/W
0
SQE Test Inhibit: Setting this bit to ‘1’ disables 10Base-T SQE
testing. By default, this bit is ‘0’ and the SQE test is performed by
generating a COL pulse following the completion of a packet
transmission.
16.10
NL10
R/W
0
10Base-T Natural Loopback: Setting this bit to ‘1’ causes transmit
data received on the TXD0-3 pins to be automatically looped back to
the RXD[0:3] pins when 10Base-T mode is enabled.
16.9
RSVD
R/W
0
Reserved
16.8
RSVD
R/W
1
Reserved
16.7
RSVD
R/W
0
Reserved
16.6
RSVD
R/W
1
Reserved
16.5
APOL
R/W
0
Auto Polarity: During auto-negotiation and 10BASE-T mode, the
78Q2120C is able to automatically invert the received signal due to a
wrong polarity connection. It does so by detecting the polarity of the
link pulses. Setting this bit to ‘1’ disables this feature.
16.4
RVSPOL
R/W
0
Reverse Polarity: The reverse polarity is detected either through 8
inverted 10Base-T link pulses (NLP) or through one burst of inverted
clock pulses in the auto-negotiation link pulses (FLP). When the
reverse polarity is detected and if the Auto Polarity feature is
enabled, the 78Q2120C will invert the receive data input and set this
bit to ‘1’. If Auto Polarity is disabled, then this bit is writeable. Writing
a ‘1’ to this bit forces the polarity of the receive signal to be reversed.
16.3:2
RSVD
R/W
0h
Reserved: Must set to ‘00’.
Page: 16 of 35
TYPE DEFAULT DESCRIPTION
R/W
(0)
Repeater Mode: When set, the 78Q2120C is put into Repeater mode
of operation. In this mode, full duplex is prohibited, CRS responds to
receive activity only and, in 10Base-T mode, the SQE test function is
disabled.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR16: Vendor Specific Register (continued)
Bit
16.1
Symbol
PCSBP
Type
R/W
Default
(0)
16.0
RXCC
R/W
0
Description
PCS Bypass Mode: When set, the 100Base-TX PCS and scrambling/
descrambling functions are bypassed. Scrambled 5-bit code groups
for transmission are applied to the TX_ER, TXD[3:0] pins and
received on the RX_ER, RXD[3:0] pins. The RX_DV and TX_EN
signals are not valid in this mode. PCSBP mode is valid only when
100Base-TX mode is enabled and auto-negotiation is disabled.
Receive Clock Control: This function is valid only in 100Base-TX
mode. When set to ‘1’, the RX_CLK signal will be held low when
there is no data being received (to save power). The RX_CLK signal
will restart 1 clock cycle before the assertion of RX_DV and be shut
off 64 clock cycles after RX_DV goes low. RXCC is disabled when
the loopback mode is enabled (MR0.14 is high). This bit should be
kept at logic zero when PCS Bypass mode is used.
MR17: Interrupt Control/Status Register
The Interrupt Control/Status Register provides the means for controlling and observing events which trigger an
interrupt on the INTR pin. This register can also be used in a polling mode via the MII Serial Interface as a means
to observe key events within the PHY via one register address. Bits 0 through 7 are status bits, which are each
set to logic one based upon an event. These bits are cleared after the register is read. Bits 8 through 15 of this
register, when set to logic one, enable their corresponding bit in the lower byte to signal an interrupt on the INTR
pin. The level of this interrupt can be set via the MR16.14 (INPOL) bit.
BIT
17.15
SYMBOL
JABBER_IE
17.14
RXER_IE
R/W
0
Receive Error Interrupt Enable
17.13
PRX_IE
R/W
0
Page Received Interrupt Enable
17.12
PDF_IE
R/W
0
Parallel Detect Fault Interrupt Enable
17.11
LP-ACK_IE
R/W
0
Link Partner Acknowledge Interrupt Enable
17.10
LS_CHG_IE
R/W
0
Link Status Change Interrupt Enable
17.9
RFAULT_IE
R/W
0
Remote Fault Interrupt Enable
17.8
R/W
0
Auto-Negotiation Complete Interrupt Enable
17.7
ANEGCOMP_IE
JAB_INT
RC
0
Jabber Interrupt: This bit is set high when a Jabber event is
detected by the 10Base-T circuitry.
17.6
RXER_INT
RC
0
Receive Error Interrupt: This bit is set high when the RX_ER signal
transitions high.
17.5
PRX_INT
RC
0
Page Received Interrupt: This bit is set high when a new page has
been received from the link partner during auto-negotiation.
17.4
PDF_INT
RC
0
Parallel Detect Fault Interrupt: This bit is set high by the autonegotiation logic when a parallel detect fault condition is indicated.
Page: 17 of 35
TYPE DEFAULT DESCRIPTION
R/W
0
Jabber Interrupt Enable
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR17: Interrupt Control/Status Register (continued)
BIT
17.3
SYMBOL
LP-ACK_INT
TYPE DEFAULT DESCRIPTION
RC
0
Link Partner Acknowledge Interrupt: This bit is set high by the
auto-negotiation logic when FLP bursts are received with the
acknowledge bit set.
17.2
LS_CHG_INT
RC
0
Link Status Change Interrupt: This bit is set when the link
transitions from an OK status to a FAIL status.
17.1
RFAULT_INT
RC
0
Remote Fault Interrupt: This bit is set when a remote fault
condition has been indicated by the link partner.
17.0
ANEGCOMP_INT
RC
0
Auto-Negotiation Complete Interrupt: This bit is set by the autonegotiation logic upon successful completion of auto-negotiation.
MR18: Diagnostic Register
BIT
18.15:13
SYMBOL
RSVD
TYPE
R
DEFAULT DESCRIPTION
00h
Reserved: Must set to ‘00h’.
18.12
ANEGF
RC
0
Auto-Negotiation Fail Indication: This bit is set when autonegotiation completes and no common technology was found. It
remains set until read.
18.11
DPLX
R
0
Duplex Indication: This bit indicates the result of the autonegotiation for duplex arbitration as follows:
0 : Half-duplex was the highest common denominator
1 : Full-duplex was the highest common denominator
18.10
RATE
R
0
Rate Indication: This bit indicates the result of the auto-negotiation
for data rate arbitration as follows:
0 : 10Base-T was the highest common denominator
1 : 100Base-TX was the highest common denominator
18.9
RXSD
R
0
Receiver Signal Detect Indication: In 10Base-T mode, this bit
indicates that Manchester data has been detected. In 100Base-TX
mode, it indicates that the receive signal activity has been detected
(but not necessarily locked on to).
18.8
RX_LOCK
R
0
Receive PLL Lock Indication: Indicates that the Receive PLL has
locked onto the receive signal for the selected speed of operation
(10Base-T or 100Base-TX).
18.7:0
RSVD
R
00h
Page: 18 of 35
Reserved: Must set to ‘00h’.
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MR19: Transceiver Control
BIT
19.15:12
SYMBOL
RSVD
TYPE
R
19.11:10
TXO[1:0]
R/W
DEFAULT DESCRIPTION
0100
Reserved
01
Transmit Amplitude Selection: Sets the transmit output amplitude
to account for transmit transformer insertion loss.
00 : Gain set for 0.0dB of insertion loss
01 : Gain set for 0.4dB of insertion loss
10 : Gain set for 0.8dB of insertion loss
11 : Gain set for 1.2dB of insertion loss
19.9:0
RSVD
R
XXXh
Reserved
MR20: Reserved
BIT
20.15:0
SYMBOL
Reserved
TYPE
na
DEFAULT DESCRIPTION
XXXXh
Reserved
TYPE
na
DEFAULT DESCRIPTION
XXXXh
Reserved
TYPE
na
DEFAULT DESCRIPTION
XXXXh
Reserved
MR21: Reserved
BIT
21.15:0
SYMBOL
Reserved
MR22: Reserved
BIT
22.15:0
SYMBOL
Reserved
Page: 19 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
ELECTRICAL SPECIFICATIONS
ABSOLUTE MAXIMUM RATINGS
Operation above maximum rating may permanently damage the device.
PARAMETER
RATING
DC Supply Voltage (Vcc)
-0.5 to 4.0 VDC
Storage Temperature
-65 to 150°C
Pin Voltage (CMOS inputs)
-0.3 to 5.5 VDC
Pin Voltage (CMOS outputs except TXOP/N)
-0.3 to (Vcc+0.6) VDC
Pin Voltage (TXOP/N only)
-0.3 to (Vcc+1.4) VDC
Pin Current
± 120 mA
RECOMMENDED OPERATING CONDITIONS
Unless otherwise noted, all specifications are valid over these temperatures and supply voltage ranges:
PARAMETER
RATING
DC Voltage Supply (Vcc)
3.3 ± 0.3 VDC
Ambient Operating Temperature (Ta)
0 to +70°C
Maximum Junction Temperature
125°C
Package Thermal Conductivity (θja)
45°C/W
DC CHARATERISTICS:
PARAMETER
SYMBOL
Supply Current
ICC
Supply Current
Page: 20 of 35
ICC
CONDITIONS
MIN
NOM
MAX
UNIT
Auto-Negotiation
48
56
mA
10BT (Idle)
26
32
10BT (Normal Activity)
88
110
100BTX
88
110
Vcc = 3.3V;
Power-down mode
© 2009 Teridian Semiconductor Corporation
5
mA
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
DIGITAL I/O CHARACTERISTICS:
Pins of type CI, CIU, CID, CIO:
PARAMETER
SYMBOL
CONDITIONS
MIN
NOM
MAX
UNIT
0.8
V
Input Voltage Low
Vil
Input Voltage High
Vih
2.0
5.5
V
Input Current
Iil, Iih
-1
1
µA
Pull-up Resistance
Rpu
Type CIU only
38
56
78
kΩ
Pull-down Resistance
Rpd
Type CID only
38
56
78
kΩ
Input Capacitance
Cin
8
pF
Pins of type CIS:
PARAMETER
SYMBOL
CONDITIONS
MIN
NOM
MAX
UNIT
Low-to-High Threshold
Vt+
1.3
1.7
V
High-to-Low Threshold
Vt-
0.80
1.20
V
Iil, Iih
-1
1
µA
Input Current
Input Capacitance
Cin
8
pF
Pins of type COZ:
PARAMETER
SYMBOL
CONDITIONS
Output Voltage Low
Vol
Iol = 4mA
Output Voltage High
Voh
Ioh = -4mA
Output Transition Time
Tt
CL = 20pF
Tristate Output Leakage
Current
Iz
MIN
NOM
MAX
UNIT
0.4
V
2.4
V
-1
6
ns
1
µA
MAX
UNIT
0.4
V
Pins of type CO:
PARAMETER
SYMBOL
CONDITIONS
Output Voltage Low
Vol
Iol = 8mA
Output Voltage High
Voh
Ioh = -8mA
Tt
CL = 20pF
Output Transition Time
MIN
NOM
2.4
V
6
ns
MAX
UNIT
0.4
V
Pins of type CIO:
PARAMETER
SYMBOL
CONDITIONS
Output Voltage Low
Vol
Iol = 4mA
Output Voltage High
Voh
Ioh = -4mA
Tt
CL = 20pF
Output Transition Time
Page: 21 of 35
© 2009 Teridian Semiconductor Corporation
MIN
NOM
2.4
V
6
ns
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
DIGITAL TIMING CHARACTERISTICS
RST Characteristics
VCC
Oscillator
RST
Treset
RST Pulse Duration
PARAMETER
RST Pulse Assertion
Page: 22 of 35
SYMBOL
Treset
CONDITIONS
VCC = 3.3V and
oscillator stabilized
© 2009 Teridian Semiconductor Corporation
MIN
30
NOM
MAX
UNIT
Oscillator
Clock
Cycles
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MII Transmit Interface
CHARACTERISTICS
SYMBOL
CONDITIONS
MIN
NOM
MAX
UNIT
Setup Time: TX_CLK to
TXD[3:0], TX_EN, TX_ER
TXSU
15
ns
Hold Time: TX_CLK to
TXD[3:0], TX_EN, TX_ER
TXHD
0
ns
CKIN-to-TX_CLK Delay
TCKIN
0
40
ns
40
60
%
MAX
UNIT
10
30
ns
40
60
%
TX_CLK Duty-Cycle
TCKIN
CKIN
TX_CLK
TXSU
TXHD
TXD[3:0]
TX_EN
or
TX_ER
Transmit Inputs to the 78Q2120C
MII Receive Interface
CHARACTERISTICS
SYMBOL
Receive Output Delay:
RX_CLK to RXD[3:0],
RX_DV, RX_ER
RXDLY
CONDITIONS
RX_CLK Duty-Cycle
MIN
NOM
RXDLY (MAX)
RX_CLK
RXDLY
RXD[3:0]
RX_DV
or
RX_ER
(MIN)
Receive Outputs from the 78Q2120C
Page: 23 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MDIO Interface Input Timing
CHARACTERISTICS
SYMBOL
CONDITIONS
MIN
NOM
MAX
UNIT
Setup Time: MDC to MDIO
MIOSU
10
ns
Hold Time: MDC to MDIO
MIOHD
10
ns
Max Frequency: MDC
Fmax
25
MHz
MAX
UNIT
MC2D
30
ns
MDIO output from high Z to
driven after MDC
MCZ2D
30
ns
MDIO output from driven to
high Z after MDC
MCD2Z
30
ns
MDC
MIOHD
MIOSU
MDIO
MDIO as an Input to the 78Q2120C
MDIO Interface Output Timing
CHARACTERISTICS
SYMBOL
MDC to MDIO data delay
CONDITIONS
MIN
NOM
MDC
MCZ2D
MC2D
MCD2Z
MDIO
MDIO as an Output from the 78Q2120C
Page: 24 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
Page: 25 of 35
1
1
Z
Z
© 2009 Teridian Semiconductor Corporation
1
Preamble
1
Preamble
1
1
1
0
Read
1
0
1
1
Write
0
Start of Operation
Frame
Code
0
Start of Operation
Frame
Code
A
A
A
A
A
A
A
PHY Address
A
PHY Address
A
A
R
R
R
R
R
R
R
R
R
R
0
1
0
Turnaround
Z
Turnaround
D D
D D
D
D
D
D
D
D
D
D
D
D
D
Data
D
Data
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
D
Z
Z
78Q2120C
10/100BASE-TX
Transceiver
MDIO Interface Output Timing
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
100BASE-TX System Timing
System timing requirements for 100BASE-TX operation are listed in Table 24-2 of Clause 24 of IEEE 802.3.
PARAMETER
CONDITION
NOM
UNIT
TX_EN Sampled to first bit of “J” on MDI
output
12
BT
First bit of “J” on MDI input to CRS assert
16
BT
First bit of “T” on MDI input to CRS
de-assert
23
BT
First bit of “J” on MDI input to COL assert
20
BT
First bit of “T” on MDI input to COL
de-assert
24
BT
TX_EN Sampled to CRS assert
RPTR = low
6
BT
TX_EN sampled to CRS de-assert
RPTR = low
6
BT
10BASE-T System Timing
PARAMETER
CONDITION
MIN
NOM
MAX
UNIT
TX_EN (MII) to TD Delay
6
BT
RD to RXD at (MII) Delay
6
BT
Collision delay
9
BT
SQE test wait
1
µs
SQE test duration
1
µs
Jabber on-time*
20
150
ms
Jabber off-time*
250
750
ms
* Guarantee by design. The specifications in the following table are included for information only.
Page: 26 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
ANALOG ELECTRICAL CHARACTERISTICS
100BASE-TX Transmitter
PARAMETER
Peak Output Amplitude (|Vp+|, |Vp-|)
(see note below)
CONDITION
MIN
Best-fit over 14 bit
times;
NOM
MAX
UNIT
950
1050
mVpk
0.98
1.02
0.5 dB Transformer
loss
Output Amplitude Symmetry
|Vp +|
|Vp -|
Output Overshoot
Percent of Vp+, Vp-
5
%
Rise/Fall time (tr, tf)
10-90% of Vp+, Vp-
5
ns
Rise/Fall time Imbalance
|tr - tf|
500
ps
Duty Cycle Distortion
Deviation from best-fit
time-grid;
±250
ps
1.4
ns
3
010101... Sequence
Jitter
Scrambled Idle
Note: Measured at the line side of the transformer.
Test Condition: Transformer P/N:
Line Termination:
TLA-6T103
100Ω ±1%
100BASE-TX Transmitter (Informative)
The specifications in the following table are included for information only. They are mainly a function of the
external transformer and termination resistors used for measurements.
PARAMETER
Return Loss
CONDITION
2 < f < 30 MHz
30 < f < 60 MHz
60 < f < 80 MHz
Open-Circuit Inductance
Page: 27 of 35
-8 < Iin < 8 mA
© 2009 Teridian Semiconductor Corporation
MIN
16
MAX
UNIT
dB
f
16 − 20 log
30 MHz
10
350
µH
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
100BASE-TX Receiver
PARAMETER
CONDITION
MIN
NOM
MAX
UNIT
Signal Detect Assertion Threshold
500
600
700
mVppd
Signal Detect De-assertion Threshold
275
350
425
mVppd
Differential Input Resistance
20
Jitter Tolerance (pk-pk)
Not tested in production
Baseline Wander Tracking
kΩ
4
ns
-75
+75
%
Signal Detect Assertion Time
Not tested
1000
µs
Signal Detect De-assertion Time
Not tested
4
µs
10BASE-T Transmitter
The Manchester-encoded data pulses, the link pulse and the start-of-idle pulse are tested against the templates
and using the procedures found in Clause 14 of IEEE 802.3.
PARAMETER
CONDITION
MIN
Peak Differential Output Signal
(see note below)
All data patterns
2.2
Harmonic Content
(dB below fundamental)
All ones data
27
NOM
MAX
UNIT
2.8
V
dB
Not tested
Link Pulse Width
Start-of-Idle Pulse Width
100
ns
Last bit 0
300
ns
Last bit 1
350
ns
Note: Measured at the line side of the transformer.
Test Condition:
Page: 28 of 35
Transformer P/N:
TLA-6T103
Line Termination:
100Ω ±1%
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
10BASE-T Transmitter (Informative)
The specifications in the following table are included for information only. They are mainly a function of the
external transformer and termination resistors used for measurements.
PARAMETER
CONDITION
MIN
Output return loss
Output Impedance Balance
1 MHz < freq < 20 MHz
NOM
MAX
UNIT
15
dB
f
29 − 17 log
10
dB
Peak Common-mode Output Voltage
50
mV
Common-mode rejection
15 Vpk, 10.1 MHz sine
wave applied to
transmitter commonmode. All data
sequences.
100
mV
Common-mode rejection jitter
15 Vpk, 10.1 MHz sine
wave applied to
transmitter commonmode. All data
sequences.
1
ns
MAX
UNIT
10BASE-T Receiver
PARAMETER
CONDITION
MIN
DLL Phase Acquisition Time
NOM
10
BT
Jitter Tolerance (pk-pk)
30
Input Squelched Threshold
500
600
700
mVppd
Input Unsquelched Threshold
275
350
425
mVppd
Differential Input Resistance
20
kΩ
10-10
Bit Error Ratio
Common-mode rejection
ns
Square wave
25
V
0 < f < 500 kHz
Not tested
Page: 29 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
VCC
C1
0.1
C2
0.1
GND
C3
0.1
GND
GND
C4
0.1
GND
VCC
C8
0.01
100
R7
R8
R9
R10
R11
R12
RXCLK
RXER
RXD3
RXD2
RXD1
RXD0
24
25
19
20
21
22
100
100
100
100
100
100
18
17
MDC
MDIO
R1
5.1K
6
RESET
VCC
7
47
44
45
46
VCC
64
2
1
1) Recommend to leave
pins 56 and 56 as NC for
78Q2120C09 device.
Connecting a resistor
between these pins as in
the 78Q2120C09 will have
no effect on this device
12
13
14
15
16
TXEN
TXCLK
TXER
TXD3
TXD2
TXD1
TXD0
TXOP
TXON
RXIP
RXIN
RXCLK
RXER
RXD3
RXD2
RXD1
RXD0
RPTR
CRS
COL
RXDV
LEDL
LEDTX
LEDRX
LEDCOL
LEDFDX
LEDBTX
LEDBT
MDC
MDIO
RST
PWRDN
ANEGA
TECH2
TECH1
TECH0
INTR
PCSBP
ISO
ISODEF
NC
NC
PHYAD4
PHYAD3
PHYAD2
PHYAD1
PHYAD0
GND
U1
78Q2120C09-CGT
TSC
LQFP64
CKIN
XTLP
XTLN
52
51
50
CRS
COL
RXDV
40
39
38
37
49
36
48
LEDL
LEDTX
LEDRX
LEDCOL
LEDFD
LED100
LED10
35
56
54
R4
49.9
1%
0603
R5
49.9
1%
0603
TD+
TDCT
TDNC1
NC2
RD+
RDCT
RD-
TX+
TXCT
TXRX+
RXCT
RX-
TLA-6T103
TDK
SMT16
VCC
C6
0.1
100 ohm
Impedance
Traces
T1
15
14
16
8
9
1
3
2
61
62
34
33
23
C12
0.1
R3
49.9
1%
0603
C5
0.01
11
12
10
R13
75
R14
75
R15
75
J1
1
2
3
4
5
6
7
8
9
10
7
5
6
R16
75
C11
0.01
1.5KV
1808
R17
75
R18
75
RJ45
CGND
Note 2: This application circuit is only
valid for the 78Q2120C09 revision.
Refer to Ordering Information for
revision identification.
INTERRUPT
Note 1
4
59
58
GND
Y1
GND
GND
GND
GND
GND
GND
GND
GND
R6
60
55
53
42
10
9
5
3
TXEN
TXCLK
TXER
TXD3
TXD2
TXD1
TXD0
28
27
26
32
31
30
29
VCC
VCC
VCC
VCC
VCC
VCC
68 ohm Impedance Traces
R2
49.9
1%
0603
100 ohm
Impedance
Traces
63
57
43
41
11
8
C7
0.01
C10
39pF
25.000MHZ
50ppm
GND
C9
39pF
GND
C9 and C10 must be calibrated
in actual application board for
25.000MHz +/-50ppm.
GND
FIGURE 1: TYPICAL APPLICATIONS CIRCUIT
Page: 30 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
ISOLATION TRANSFORMERS
Two simple 1:1 isolation transformers are required at the line interface. Transformers with integrated commonmode choke are recommended for exceeding FCC requirements. This table gives the recommended line
transformer characteristics:
NAME
VALUE
CONDITION
Turns Ratio
1 CT : 1 CT ± 5%
Open-Circuit Inductance
350 µH (min)
@ 10 mV, 10 kHz
Leakage Inductance
0.40 µH (max)
@ 1 MHz (min)
Inter-Winding Capacitance
25 pF (max)
D.C. Resistance
0.9 Ω (max)
Insertion Loss
0.4 dB (typ)
HIPOT
1500 Vrms
0 - 65 MHz
Note: The 100Base-TX amplitude specifications assume a transformer loss of 0.4 dB. For the transmit line
transformer with higher insertion losses, up to 1.2 dB of insertion loss can be compensated by selecting the
appropriate setting in the Transmit Amplitude Selection bits in register MR19.11:10.
REFERENCE CRYSTAL
If the internal crystal oscillator is to be used, a crystal with the following characteristics should be chosen:
NAME
VALUE
UNITS
Frequency
25.00000
MHz
Load Capacitance*
4**
pF
Frequency Tolerance
±50
PPM
±2
PPM/yr
±5
PPM
Aging
o
Temperature Stability ( 0 - 70 C)
Oscillation Mode
o
Parallel Resonance, Fundamental Mode
o
Parameters at 25 C ± 2 C ; Drive Level = 0.5 mW
Drive Level
50 - 100
µW
Shunt Capacitance (max)
8
pF
Motional Capacitance (min)
10
fF
Series Resistance (max)
60
Ω
Spurious Response (max)
> 5 dB below main within 500 kHz
* Equivalent differential capacitance across the XTLP/XTLN pins.
** If crystal with a larger load is used, external shunt capacitors to ground should be added to make up the
equivalent capacitance difference.
Page: 31 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
Tr
CKIN
Tf
Tclkper
Tclkhi
External CKIN Oscillator Characteristics
EXTERNAL CKIN OSCILLATOR CHARACTERISTICS
PARAMETER
CKIN Frequency
CKIN Period
SYMBOL
Absolute Jitter
MIN
NOM
MAX
UNIT
f
See Note 1
25.000
MHz
Tclkper
See Note 1
40
ns
CKIN Duty Cycle
Rise / Fall Time
CONDITION
Tclkhi / Tclkper
Tr, Tf
Input signaling
requirements = CI
45
55
%
4.0
ns
0.1
ns
Note 1: IEEE 802.3 frequency tolerance ±50 ppm
Page: 32 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
PACKAGE PIN DESIGNATIONS
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
RPTR
LEDFDX
GND
NC
GND
RXIP
RXIN
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
34
33
78Q2120C
LEDBT
ANEGA
TECH0
TECH1
TECH2
VCC
GND
VCC
LEDL
LEDTX
LEDRX
LEDCOL
LEDBTX
INTR
CRS
COL
Page: 33 of 35
© 2009 Teridian Semiconductor Corporation
TXD3
TXD0
TXD1
TXD2
TX_ER
TX_CLK
TX_EN
RX_DV
RX_CLK
RX_ER
RXD2
RXD1
RXD0
MDIO
MDC
RXD3
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
ISODEF
ISO
GND
CKIN
GND
RST
PWRDN
VCC
GND
GND
VCC
PHYAD4
PHYAD3
PHYAD2
PHYAD1
PHYAD0
54
53
52
VCC
NC
GND
XTLP
XTLN
VCC
TXON
TXOP
64
63
62
61
60
59
58
57
56
55
PCSBP
(Top View)
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
MECHANICAL SPECIFICATIONS
64-LQFP (Top View)
11.7 (0.460)
12.3 (0.484)
11.7 (0.460)
+
12.3 (0.484)
PIN No. 1 Indicator
9.8 (0.386)
10.2 (0.402)
0.50 (0.0197) Typ.
0.60 (0.024) Typ.
Page: 34 of 35
0.14 (0.006)
0.28 (0.011)
© 2009 Teridian Semiconductor Corporation
0.00 (0)
0.20 (0.008)
1.40 (0.055)
1.60 (0.063)
Rev 1.3
78Q2120C
10/100BASE-TX
Transceiver
ORDERING INFORMATION
PART DESCRIPTION
ORDER NUMBER
78Q2120C (Revision 9) 64-pin LQFP
78Q2120C (Revision 9) 64-pin LQFP - Lead Free
PACKAGE MARK
78Q2120C09-64CGT
78Q2120C-CGT
xxxxxxxxxxx9
78Q2120C09-64CGT/F
78Q2120C-CGT
xxxxxxxxxxx9F
REVISION HISTORY
Rev. #
1.0
1.1
1.2
1.3
Date
September 2004
January 2005
August 2005
January 2009
Comments
Final Data Sheet release
1. Revised ordering number (added 64)
2. Changed CKIN table title
Company name and logo change
Revised ordering number (deleted A)
No responsibility is assumed by Teridian Semiconductor Corporation for use of this product or for any
infringements of patents and trademarks or other rights of third parties resulting from its use. No license is granted
under any patents, patent rights or trademarks of Teridian Semiconductor Corporation, and the company reserves
the right to make changes in specifications at any time without notice. Accordingly, the reader is cautioned to
verify that the data sheet is current before placing orders.
Teridian Semiconductor Corporation, 6440 Oak Canyon Rd. Suite 100, Irvine, CA 92618
(714) 508-8800, FAX: (714) 508-8877, http://www.teridiansemiconductor.com
Page: 35 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3