By Stephen Scearce

Abstract:

The glass weave effect on 56Gbps PAM-4 systems have shown bit error rate issues in the lab. Our lab results show that our PAM-4 systems are more sensitive for PN skew than previous generations of NRZ with the same UI. For the current generation of designs we must consider glass direction, glass type, and weave density. The stackup decisions are based on the measured network parameters, TDR, silicon BER, and eye diagram measurement results. Techniques used to mitigate the unbalance effect of the glass weave with differential pairs are discussed and statistical measurement results will be shared.

Stephen Scearce serves as a Principal Engineer/Engineering Manager of Cisco’s Electronics Packaging and Diagnostics team. Stephen provides the technical direction/leadership for Signal Integrity, Power Integrity, Mechanical/Thermal Design, and Software Diagnostics Design in US/China. He has global responsibility for Cisco’s Enterprise Routing, Wireless, Core Switching, and Security product lines. Stephen has worked for Cisco for 19 years focused on ASIC/System PI, SI, Package Design, and EMC Design. Prior to working at Cisco, Stephen worked for NASA LaRC in the Electromagnetic Research Branch HIRF team. Stephen holds seven U.S. issued patents, and has co-authored 15 papers.

As an IEEE EMC Society volunteer, he has served on the IEEE EMC+SIPI symposium committee for seven years and is currently the Treasurer for the EMC+SIPI 2022 Symposium in Spokane, WA.

Next up? Are you interested in learning more about recent advancements in EMC, Signal and Power Integrity technologies? If so, join us IN-PERSON August 1-5, 2022 for the 2022 IEEE INTERNATIONAL SYMPOSIUM ON ELECTROMAGNETIC COMPATIBILITY, SIGNAL & POWER INTEGRITY.