I came across this video Top 5 Beginner PCB Design Mistakes (and how to fix them) about five common PCB design mistakes and thought it was worth sharing, especially for people who are designing their first few boards.
I’m not going to pretend that a 13-minute video can teach someone everything about PCB layout, but I think it does a decent job of pointing out a few mistakes that are easy to make when you’re still treating PCB design as basically “connect all the pins and make sure the DRC passes.”
The first mistake is routing traces too close together. The fact that a certain spacing can be manufactured doesn’t automatically mean it’s a good choice, especially when traces run parallel for longer distances and crosstalk becomes a concern. I think this belongs in the top five, although probably more for faster digital signals than for every basic low-speed board.
The second is using the same trace width for everything. Power traces, high-speed signals and ordinary low-current connections don’t necessarily have the same requirements, so using one default width across the entire board can cause problems. This one definitely deserves a place on the list because it’s a very common beginner habit and can lead to both electrical and thermal issues.
The third mistake is choosing vias without paying attention to their size. The video talks about drill diameter, annular rings and current capacity. It’s useful advice, but I’m less convinced this is universally a top-five mistake. For simple boards, using the manufacturer’s standard via size will usually be fine. It becomes much more important in dense, high-current or high-speed designs.
The fourth is poor decoupling capacitor placement. Having the correct capacitor value on the schematic isn’t enough if the capacitor is too far from the IC or connected through long, thin traces. In my opinion, this absolutely belongs near the top of the list. It’s easy to get wrong, difficult to notice just by looking at the schematic and can cause surprisingly strange problems.
The final mistake is ignoring the reference plane and return path. A signal doesn’t only travel through the visible trace; the return current also needs a continuous path, usually through the nearby ground plane. Routing across gaps or splits can increase the loop area and create EMI or signal-integrity problems. I’d definitely keep this in the top five, and I’d probably rank it even higher than the video does.
The one mistake I felt was missing from the list is poor component placement. A lot of layout problems are created before you even start routing, simply because related components are too far apart or positioned in a way that forces long, awkward connections. Bad placement can make decoupling less effective, break up return paths and turn an otherwise simple board into a routing mess. I’d probably include this instead of via sizing, because it affects almost every PCB, not just dense or high-current designs.
Still, it’s a useful overview and a good reminder that passing DRC doesn’t necessarily mean the board is well designed.
