Tool/software:
Hi team!
We have a problem bringing up a PCIe link that has the DS125BR401 and a mux/demux (PI3PCIE3412A) between the Root complex and the Endpoint. The block diagram of the path between the redriver and the Endpoint is:
We know the link works fine if the mux/demux is bypassed. We suspect that the problem might be the common voltage of the differential pairs. The mux/demux has the following electrical characteristics:
In the datasheet of the DS125BR401 it is stated that the inputs are terminated to VCC (CML input), so that DC component would reach the mux/demux as there is no coupling capacitors between them. Is that right? Could adding those capacitor fix the issue by isolating DC voltage levels?
Thank you!