Skew-Induced Insertion Loss Deviation (SILD) and FOM_SILD: Metrics for Quantifying P/N Skew Effects in High-Speed Channels

TL;DR

This paper introduces new metrics, SILD and FOM_SILD, to quantify P/N skew effects in high-speed interconnects, validated through simulations and measurements, aiding the design of ultra-fast data links.

Contribution

The paper presents novel analytical metrics, SILD and FOM_SILD, specifically designed to evaluate P/N skew impacts in high-speed SerDes channels, addressing limitations of existing methods.

Findings

FOM_SILD shows reciprocity with measured S-parameters.

Simulation results correlate strongly with BER trends.

Metrics provide a robust framework for skew analysis in ultra-high-speed channels.

Abstract

The rise of AI workloads and growing data center demands have driven the need for ultra-high-speed interconnects exceeding 200 Gb/s. As unit intervals (UI) shrink, even a few picoseconds of P/N skew can degrade serializer-deserializer (SerDes) performance. Traditional methods for quantifying skew fall short in capturing its impact. We introduce two new metrics: 1) Skew-Induced Insertion Loss Deviation (SILD) and 2) its complementary Figure of Merit (FOM_SILD), analytically developed to assess P/N skew effects. Measured S-parameters confirm FOM_SILD reciprocity, while simulations of 224G PAM4 SerDes show strong correlation with bit error rate (BER) trends. This approach offers a robust framework for analyzing skew in next-generation ultra-high-speed interconnects.