Sorry in advance I am fairly new to the electronics world and Ethernet signaling. I am a physics postgrad student doing some hardware work rather than an electronics engineering background.
I have to connect two ethernet modules on a backplane PCB over Ethernet. The modules are pre-made and I have no choice but to use them. Since they are on the same board and in very close proximity I am trying to eliminate the magnetics modules.
One of the devices uses a KSZ9031 ethernet PHY by Microchip for which there is lots of documentation and the other uses a BCM54210 ethernet PHY by Broadcom which unfortunately there is virtually no published information.
I have been researching capacitive coupling of Ethernet and dug out this:
So it seems that by luck this is a good choice as it has termination and voltage mode interfaces on board. So far so good, just stick a capacitor in each line.
But this assumed that both ethernet PHYs are the same.
More generally both Microchip and Texas Instruments both publish documents like these:
which show me how to couple and terminate for PHYs that either have an internal DC bias or without an internal DC bias.
Since I do not know anything about the second PHY by Broadcom including termination and DC voltage bias how do I know which circuit type to pick?
Also, if anyone has any information they know about the Broadcom ethernet PHY I would love to know and if anyone has any general hints or experience with capacitively coupling ethernet that would be great too!
Thanks very much :)