1.25Gbps 40km Duplex LC SFP Transceiver
PSP12-3140
Primus IT Limited
Page 6
Pin Descriptions
Transmitter Fault Indication
Receiver Loss of Signal Indicator (Active
high, open-drain)
Notes:
Plug Seq.: Pin engagement sequence during hot plugging.
1. TX Fault is an open collector output, which should be pulled up with a 4.7k~10kΩ resistor on the host board
to a voltage between 2.0V and Vcc+0.3V. Logic 0 indicates normal operation; Logic 1 indicates a laser fault of
some kind. In the low state, the output will be pulled to less than 0.8V.
2. TX Disable is an input that is used to shut down the transmitter optical output. It is pulled up within the
module with a 4.7k~10kΩ resistor. Its states are:
Low (0 to 0.8V): Transmitter on;
Between (>0.8V, < 2.0V): Undefined;
High (2.0 to 3.465V): Transmitter Disabled;
Open: Transmitter Disabled.
3. Mod-Def0, 1, 2: These are the module definition pins. They should be pulled up with a 4.7k~10kΩ resistor on
the host board. The pull-up voltage shall be VccT or VccR.
MOD_DEF (0) is grounded by the module to indicate that the module is present.
MOD_DEF (1) is the clock line of two wire serial interface for serial ID SCL.
MOD_DEF (2) is the data line of two wire serial interface for serial ID SDA.
4. LOS is an open collector output, which should be pulled up with a 4.7k~10kΩ resistor. Pull up voltage
between 2.0V and Vcc+0.3V. Logic 1 indicates loss of signal; Logic 0 indicates normal operation. In the low
state, the output will be pulled to less than 0.8V.
5. RD-/+: These are the differential receiver outputs. They are internally AC-coupled 100 differential lines which
should be terminated with 100Ω (differential) at the user SERDES.
6. TD-/+: These are the differential transmitter inputs. They are internally AC-coupled, differential lines with
100Ω differential termination inside the module.