Delta Electronics Network Device LCP-1250 Specification page 6

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.
Recommend Circuit Schematic
Protocol Vcc
Tx_Disable
Tx_Fault
Protocol IC
Rx_LOS
DELTA ELECTRONICS, INC.
VCC 3.3V
RES1
SerDes IC
100 Ohms*
3.3V
RES1
PLD / PAL
RES1 = 4.7k to 10k Ohms
* Depands on SerDes IC used
1uH
1uH
10uF 0.1uF
0.1uF
Tx_Disable
Tx_Fault
TD +
TD -
VeeT
RES1
10uF 0.1uF
RD +
RD -
Rx_LOS
VeeR
RES1 RES1
Mod_def 2
Mod_def 1
Mod_def 0
6
DELTA SFP Module
VccT
10k Ohms
0.01uF
Laser Driver
100 Ohms
0.01uF
VccR
Preamp &
0.01uF
Quantizer
0.01uF
EEPROM
Nov., 2006
www.deltaww.com
Laser Diode
Photo Diode
Rev. 6B