Delta Electronics Single Mode SFP Transceiver LCP-1250B4QDRx - Manual (Page 5)

DELTA ELECTRONICS, INC.
5 2008/1/23
Rev. 6G
www.deltaww.com
Notes:
1) TX Fault is an open collector/drain output, which should be pulled up with a 4.7K – 10KΩ resistor on
the host board. Pull up voltage between 2.0V and VccT, R+0.3V. When high, output indicates a laser
fault of some kind. Low indicates normal operation. In the low state, the output will be pulled to < 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 4.7 – 10 K Ω resistor. Its states are:
Low (0 – 0.8V):
Transmitter on
(>0.8, < 2.0V): Undefined
High (2.0 – 3.465V): Transmitter Disabled
Open:
Transmitter Disabled
3) Mod-Def 0,1,2. These are the module definition pins. They should be pulled up with a 4.7K –
10KΩresistor on the host board. The pull-up voltage shall be VccT or VccR (see Section IV for further
details). 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 Mod-Def 2 is the data line of two wire serial interface
for serial ID
4) LOS (Loss of Signal) is an open collector/drain output, which should be pulled up with a 4.7K – 10KΩ
resistor. Pull up voltage between 2.0V and VccT, R+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 < 0.8V.
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. The voltage swing on these lines will be between
370 and 2000 mV differential (185 – 1000 mV single ended) when properly terminated.
7) VccR and VccT are the receiver and transmitter power supplies. They are defined as 3.3V ±5% at the
SFP connector pin. Maximum supply current is 300mA. Recommended host board power supply
filtering is shown below. Inductors with DC resistance of less than 1 ohm should be used in order to
maintain the required voltage at the SFP input pin with 3.3V supply voltage. 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. 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.