Issue link: https://iconnect007.uberflip.com/i/1518649
50 DESIGN007 MAGAZINE I APRIL 2024 eling tool can flag where stub length becomes an issue and direct the PCB technologist or designer to deploy back drilling in the appro- priate cases. Via Documentation Fills a Variety of Applications Aside from backdrilling, where the unused stub of the via is removed, vias can be treated in myriad ways to suit the specific application or functional area of the PCB. In high-power applications, the via may be copper or conduc- tive epoxy-filled. Both methods aid in reduc- ing the resistance of the via; aiding high-power applications have the added benefit of increas- ing the thermal conductivity and helping heat exit the PCB in a managed way. Vias may also be filled non-conductively sim- ply to prevent the entrapment of contaminants and for increased reliability. e variety of options and implications of getting the via fills and styles incorrect mean that clear documentation is vital for supply chain communication. Conclusion I started my column talking about Polar's informal ban on business speak—no reaching out. We email or call each other, no "going forward," no "dog and pony shows," "deep dives" (unless compressed gasses and seawater are involved), and certainly no circling back or "Let's 'park- ing lot' this." So, why does the title focus on drilling down? It must be on the list of "ver- boten" words and phrases. In this case, I used the words lit- erally as this article is all about Figure 2: Via stub length backdrilled to 20 mils gives a green light at 4 Gbit/s data rate. Find the math behind this in Signal and Power Integrity Simplified, by Dr. Eric Bogatin. Figure 3: To fill or not to fill?