Issue link: https://iconnect007.uberflip.com/i/1529118
8 DESIGN007 MAGAZINE I NOVEMBER 2024 Rules of thumb are everywhere. I took an auto mechanics class when I was 16, and I still remember the instructor telling us, "Remem- ber, the cause of the problem is usually the simplest thing." at holds true for much of life, actually. ere are hundreds of rules of thumb for PCB design. ey're built on design formulas, fabricators' limitations, and tribal knowledge. Unfortunately, some longtime rules of thumb should be avoided at all costs. We wanted to get to the bottom of rules of thumb, so we sur veyed readers. Here are a few of the interesting answers that readers provided, edited slightly for clarity. What rules of thumb do you utilize regularly, and why? • Avoid 90° and acute angle routing to prevent acid traps. • Higher than 1GHz = high speed; lower = I don't care. • 2x dielectric (approximation) thickness for 50-ohm RF traces. When is it time to "do the science" instead of using a rule of thumb? The Shaughnessy Report by Andy Shaughnessy, I-CONNECT007 A Handy Look at Rules of Thumb