location of pcie AC-couple cap

[lu_chunjie23]

For T1040 (PCIe Gen 2.0 run @5Gbps) , if the  PCIe Tx&Rx chips are on same pcb, could the ac-coulpe caps of PCIe link be placed on the Rx side?

Will the eye pattern be better than the caps placed on Tx side?

[r8070z]

Have a great day,

The serdes can operates when the AC-coulpe caps of link are placed on the Rx side. For example AC coupling caps for SGMII are placed near the receiver inputs (standard). So if PCIe Tx&Rx chips are fixed on the same pcb, the ac-coulpe caps of PCIe link can be placed on the Rx side. I do not see why the eye pattern be better in this case. You should ensure by simulation that the Rx data eyes at each link partner’s receiver is in spec in both cases.

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