Oplink Communications, Inc.

Application Notes

Electrical interface: All signal interfaces are compliant with

the SFP MSA specification. The high speed DATA interface

is differential AC-coupled internally with 0.1μF and can be

directly connected to a 3.3V SERDES IC. All low speed control

and sense output signals are open collector TTL compatible

and should be pulled up with a 4.7 - 10kΩ resistor on the

host board

Loss of Signal (LOS): The Loss of Signal circuit monitors

the level of the incoming optical signal and generates a logic

HIGH when an insufficient photocurrent is produced.

TX_Fault: The output indicates LOW when the transmitter

is operating normally, and HIGH with a laser fault including

laser end-of-life. TX Fault is an open collector/drain output

and should be pulled up with a 4.7 - 10kΩ resistor on the

host board.TX Fault in non-latching (automatically deasserts

when fault goes away).

TX_Disable: When the TX Disable pin is at logic HIGH, the

transmitter optical output is disabled (less than -45dBm).

Serial Identification and Monitoring: The module

definition of SFP is indicated by the three module definition

pins, MOD_DEF(0), MOD_DEF(1) and MOD_DEF(2).

Upon power up, MOD_DEF(1:2) appear as NC (no connection),

and MOD_DEF(0) is TTL LOW. When the host system detects

this condition, it activates the serial protocol (standard

signal (SCL). The positive edge clocks data into the EEPROM

segments of the SFP that are not write protected, and the

negative edge clocks data from the SFP.

The serial data signal (SDA) is for serial data transfer. The

host uses SDA in conjunction with SCL to mark the startand

end of serial protocol activation. The supported monitoring

functions are internal temperature, supply voltage, bias

current, transmitter power, average receiver signal, all alarms

and warnings and software monitoring of TX Fault/LOS. The

device is internally calibrated.

The data transfer protocol and the details of the mandatoryand

vendor specific data structures are defined in the SFPMSA, and

SFF-8472, Rev. 9.4

Power supply and grounding: The power supply line

shouldbe well-filtered. All 0.1μF power supply bypass

capacitors should be as close to the transceiver module

as possible.

Example of SFP host board schematic

Laser Safety: All transceivers are Class I Laser

products per FDA/CDRH and IEC-60825 stan-

dards. They must be operated under specified

operating conditions.

Oplink Communications, Inc.

DATE OF MANUFACTURE:

This product complies with

21 CFR 1040.10 and 1040.11

Meets Class I Laser Safety Requirements

TRPA48M Single Mode

RevC.2008.04.01

R: 4.7 to 10kΩ

4

TRPA48M