Table 2. 20-pin Connection Diagram Description
Pin
1
Name
Function/Description
MSA Notes
VEE
T
Transmitter Ground
2
TX Fault
Transmitter Fault Indication - High Indicates a Fault
Transmitter Disable - Module disables on high or open
Module Definition 2 - Two wire serial ID interface
Module Definition 1 - Two wire serial ID interface
Module Definition 0 - Grounded in module
Not Connected
Note 1
Note 2
Note 3
Note 3
Note 3
3
TX Disable
MOD-DEF2
MOD-DEF1
MOD-DEF0
Rate Select
LOS
4
5
6
7
8
Loss of Signal - High Indicates Loss of Signal
Receiver Ground
Note 4
9
VEE
VEE
VEE
R
R
R
10
11
12
13
14
15
16
17
18
19
20
Receiver Ground
Receiver Ground
RD-
Inverse Received Data Out
Received Data Out
Note 5
Note 5
RD+
VEE
R
Receiver Ground
VCC
VCC
R
T
Receiver Power - 3.3 V +/- 5%
Transmitter Power - 3.3 V +/- 5%
Transmitter Ground
Note 6
Note 6
VEE
T
TD+
TD-
Transmitter Data In
Note 7
Note 7
Inverse Transmitter Data In
Transmitter Ground
VEE
T
Notes:
1. TX Fault is not used and is always tied to ground through a 100 ohm resistor.
2. TX Disable as described in the MSA is not applicable to the 1000BASE-T module, but is used for convenience as an input to reset the internal
ASIC. This pin is pulled up within the module with a 4.7 K resistor.
Low (0 – 0.8 V):
Transceiver on
Between (0.8 V and 2.0 V): Undefined
High (2.0 – 3.465 V):
Open:
Transceiver in reset state
Transceiver in reset state
3. Mod-Def 0,1,2. These are the module definition pins. They should be pulled up with a 4.7-10 K resistor on the host board to a supply less than
T + 0.3 V or V R + 0.3 V.
V
CC
CC
Mod Def 0 is tied to ground through a 100 ohm resistor to indicate that the module is present.
Mod-Def 1 is clock line of two wire serial interface for optional serial ID
Mod-Def 2 is data line of two wire serial interface for optional serial ID
4. LOS (Loss of Signal) operation on the 1000BaseT SFP is different than for optical SFP applications. For models with RX_LOS enabled, RX_LOS
signal is a 1000BASE-T linkup/link-down indicator and not a peak (AC) or voltage (DC) detector. For models where RX_LOS is disabled, RX_LOS
is not used and is always tied to ground via 100-ohm resistor.
5. RD-/+: These are the differential receiver outputs. They are ac coupled 100 differential lines which should be terminated with 100 differential
at the user SerDes. The ac coupling is done inside the module and is thus not required on the host board. The voltage swing on these lines
will be between 370 and 2000 mV differential (185 – 1000 mV single ended) when properly terminated. These levels are compatible with CML
and LVPECL voltage swings.
6.
V R and V T are the receiver and transmitter power supplies. They are defined as 3.3 V 5% at the SFP connector pin. The maximum supply
CC CC
current is 317 mA and the associated in-rush current will typically be no more than 30 mA above steady state after 500 nanoseconds.
7. TD-/+: These are the differential transmitter inputs. They are ac coupled differential lines with 100 differential termination inside the module.
The ac coupling is done inside the module and is thus not required on the host board. The inputs will accept differential swings of 500 – 2400
mV (250 – 1200 mV single ended), though it is recommended that values between 500 and 1200 mV differential (250 – 600 mV single ended)
be used for best EMI performance. These levels are compatible with CML and LVPECL voltage swings.
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