Design Strategies for Skew Compensation in Highspeed PCB Strip Line Interconnects

This paper presents a comprehensive analysis of the impact of intra-pair PN skew compensation in printed circuit board (PCB) strip line (SL) traces, for a high-speed 224 Gbps lane for the first time. The study investigates the effects of skew compensation placement both with and without via discontinuities. Detailed evaluations are performed in both time and frequency domains, examining critical parameters such as time-domain reflectometry (TDR), input impedance, return loss, insertion loss, and common-mode S -parameters. The findings reveal that, in a simple strip line trace without via discontinuities, the location of skew compensation has negligible influence on signal margins. However, when via discontinuities are introduced, the impact becomes significant on signal margins and common-mode conversion. This highlights the crucial role of skew compensation placement in high-speed designs, where increasingly tight performance margins and reduced <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P C B$</tex> dimensions exacerbate signal integrity challenges. The results underscore the importance of careful design considerations to optimize performance in modern high-speed interconnects.