Crosstalk Analysis in Add-In Card structure for High-Speed SerDes Channels with PCIe Gen6

With the increasing demand for high-performance computing (HPC), the significance of high-speed SerDes channels is growing. An importance of crosstalk is larger than ever, in particular, peripheral component interconnect express (PCIe) Gen6 uses pulse amplitude modulation of four-level (PAM4), not non-return-to-zero (NRZ). In this paper, minimizing crosstalk Add-in Card (AIC) based on the network parameters and specific example of enhancement with reinforcement grounding is presented. And its effectiveness of that is evaluated in NRZ and PAM4 modulations. As a result, the crosstalk effect caused by the AIC's ground return path in NRZ is negligible, but case of PAM4, it has a significant impact that can directly degrade the signal quality.