FN-TRAN-SFP28-LR-FL Fortinet FN-TRAN-SFP28-LR Compatible 25GBASE-LR SFP28 Transceiver, 1310nm, 10km, SMF, Duplex LC

1. Measured at 25.78125Gb/s, ER > 3.5dB, PRBS 2³¹−1, BER better than or equal to 5×10⁻⁵.

Plug Seq.: Pin engagement sequence during hot plugging.

1. TX Fault is an open-collector/drain output, which should be pulled up with a 4.7–10 kΩ resistor on the host board. Pull-up voltage between 2.0V and VccT + 0.3V. When high, the output indicates a laser fault of some kind. Low indicates normal operation. In the low state, the output will be pulled to < 0.4V.
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 4.7–10 kΩ resistor. Its states are: Low (−0.3 to 0.8V): Transmitter on · (> 0.8V, < 2.0V): Undefined · High (2.0V to VccT + 0.3V): Transmitter disabled · Open: Transmitter disabled.
3. MOD_ABS shall be pulled up with a 4.7–10 kΩ resistor on the host board. The pull-up voltage shall be VccT or VccR.
4. LOS (Loss of Signal) is an open-collector/drain output, which should be pulled up with a 4.7–10 kΩ resistor. Pull-up voltage between 2.0V and VccR + 0.3V. When high, this output indicates the received optical power is below the worst-case receiver sensitivity (as defined by the standard in use). Low indicates normal operation. In the low state, the output will be pulled to < 0.4V.
5. VeeR and VeeT may be internally connected within the SFP module.
6. RD-/+: These are the differential receiver outputs. They are AC-coupled 100Ω differential lines which should be terminated with 100Ω (differential) at the user SerDes. The AC coupling is done inside the module and is thus not required on the host board.
7. VccR and VccT are the receiver and transmitter power supplies. They are defined as 3.3V ±5% at the SFP connector pin. Inductors with DC resistance of less than 1Ω should be used in the host board power supply filter in order to maintain the required voltage at the SFP input pin with a 3.3V supply. When the recommended supply filtering network is used, hot plugging of the SFP transceiver module will result in an inrush current of no more than 30mA greater than the steady-state value. VccR and VccT may be internally connected within the SFP transceiver module.
8. TD-/+: These are the differential transmitter inputs. They are AC-coupled differential lines with 100Ω differential termination inside the module. The AC coupling is done inside the module and is thus not required on the host board.
9. Internally pulled down per SFF-8431 Rev 4.1.