I have a question regarding SFP pin requirements. The SFP pin descriptions can be found in the standard document found here.
I'm currently designing a high speed LED transmitter and PIN-TIA receiver with SFP interface. This is meant to be used with a typical simple SFP media converter like the one shown found here. I do not design the media converter, only the SFP-interface transceiver.
In theory, referring to the SFP pins on the SFP host side, I'm only planning to use the Power pins, Ground pins, TD+ and TD- pins, and RD+ and RD- pins.
I do not intend to use the following pins:
- TX Fault
- TX Disable
- MOD-DEF1, MOD-DEF2, MOD-DEF3
- Rate Select
My question is, can I just leave the pins above floating? Examples of my concerns are:
- TX Fault & Disable: If they are floating, would it somehow affect the output of the TD+ and TD- pins? These pins are normally connected to a typical laser driver chip, which I'm not using. I just have an LED (in-house developed) as s transmitter.
- MOD-DEF: I understand this is meant to connect to an EEPROM for transceiver module details etc, which I'm not interested in in this simple media converter. Does that mean I can just leave it open.
- LOS: This is normally connected to a LOS pin on the limiting amplifier on a ROSA. But my TIA has a built-in amplifier and does not have a LOS pin. Can i leave this pin floating?
- Rate Select: Do I simply tie this high to get a 'full bandwidth'? What does 'reduced bandwidth' even mean? Is it 100Mbps vs 1000Mbps kinda thing?