Issue link: https://iconnect007.uberflip.com/i/1537388
20 DESIGN007 MAGAZINE I JULY 2025 I'd like to reminisce about the days of old when PCB design was a more straightforward process. Now and then, I find it grounding to reflect on where we started and how far we've come. I remember the long hours spent at the light table, carefully laying down black tape to shape each trace, cutting and aligning pads with surgical precision on sheets of Mylar. I often went home with nicks on my fingers from the X-Acto knives and bits of tape all over me. It was as much an art form as it was an engineering task—tac- tile and methodical, requiring the patience of a sculptor. Those days are long gone. A lot has changed in PCB design over the years. One of those sig- nificant areas of change is the E L E M E N TA RY, M R . WATS O N Rein in Your Design Constraints by J ohn Watson, CID area of design constraints, the theme for this issue. Not too long ago, your projects were guided by design rule checks (DRC). In the traditional PCB design workflow, usually at the end of your design, you would then set up the design's rules and checks and see how "close" you got. The DRC acted as a safety net, typically running after the lay- out was completed to catch violations such as trace spacing, component clearance, or minimum via size. These were reactive checks applied late in the process. However, today, we have shifted away from a reactive sys- tem to a proactive system called design rule constraints, which are set up and defined before and during the design process. These constraints, as the name implies, constrain what you can do in the design. Design constraints offer many significant advantages, includ- ing helping designers catch problems early in the process. While you're working on a design, the software checks your work as you go. If something goes awry or you violate the rules, perhaps placing two lines too close together, the program will prevent you from routing those two traces at all. Another great benefit of design constraints is that they help facilitate teamwork. If one designer is working on one section of