Issue link: https://iconnect007.uberflip.com/i/1419905
OCTOBER 2021 I PCB007 MAGAZINE 77 Figure 7a: A TDR comparison of a high-speed signal propagation (impedance) through vertical connections of a back-drilled PTH vs. a back-drilled VeCS-1 vertical trace seen in Figure 7b. (Source: BestPCB) Figure 7b: Four figures of a high-speed signal propagation (impedance) through the back-drilled VeCS-1 connections; 7b1: Top view of test board schematic; 7b2: TDR measurements along test traces; 7b3: Top photo of test board; 7b4: X-ray image of the shielded VeCS-1 vertical connection to inner layers. 1 & 9: Molex 72351-1851 and launch via; 2 & 8: A short single-end routing on L1; 3 & 7: Differential routing on L1; 4 & 6: Test via (VeCS-1 or PTH); 5: Differential routing on inner layer. (Source: BestPCB and WUS Printed Circuit Co.) Figure 7c: A top view of the VeCS-1 vertical connections with plated ground shield as seen in Figure 7b4. (Source: NextGIn and WUS) b3 b1 b2 b4