Does the three SerDes Ports have AC coupling capacitors on board for Transmit Data Bus Positive lines or should we provide it on our custom carrier card? Do these have TVS diodes on board?
The three SerDes port don’t have any AC coupling capacitors on the data bus lines.
In general, the SFP specification (https://members.snia.org/document/dl/26184) defines that the AC capacitors should be included inside the SFP module, not on the host board (see the snippet from the standard below).
This is why we don’t put AC capacitors on either UbiSwitch Module, or the baseboard, because when using the baseboard with an SFP, the SFP that gets plugged in will contain the AC capacitors.
So, if you connecting the SERDES ports to an SFP module, you don’t need AC capacitors on the SERDES lines. However if you are connecting the SERDES ports directly to an ethernet PHY on your board, then you should add 0.1uF AC capacitors in series with the SERDES lines.
We don’t put TVS diodes on the SERDES ports; in general we wouldn’t recommend doing that as it can affect signal integrity.