The Isolation Effectiveness of Ground Via Stitches in High-Speed Board Designs

摘要

Because the speed of signals continues to rise, controlling crosstalks between close signal passages becomes increasingly critical, especially for high-speed links on high-density boards. Ground stitching vias are important tools used by industries to enhance the isolation performance. However, the level of their effectiveness for very high-speed links and their significance in the whole signal link were seldom reported. In this work, we provide comprehensive studies of the effectiveness of ground stitching vias for high-speed signal crosstalks up to 40 GHz. Comparisons are made to verify the effectiveness and isolation level that could be introduced by stitching vias to highspeed differential signals. Also the stitching via contribution to the full path crosstalk distribution is analyzed and discussed. The conclusions and summaries developed from these comparisons and analysis provide effective guidelines for highspeed link designs.