Issue link: https://iconnect007.uberflip.com/i/1529118
34 DESIGN007 MAGAZINE I NOVEMBER 2024 Feature Article by Patrick Davis CADENCE DESIGN SYSTEMS Just because a "rule of thumb" is usually based on experience instead of precise facts doesn't negate its value. For instance, when I told my kids that a good rule of thumb was not to back-talk to their mother, they discovered very quickly how accurate my advice was once they crossed that line. ere are a lot of rules of thumb that we rely on daily, including those that apply to PCB design. While many aspects of PCB layout are gov- erned by procedures, standards, and work- flows, there is still much that belongs only to tribal knowledge. Unless this knowledge is collected, documented, and incorporated into a design database, it will only exist in the infor- mation that gets passed from one designer to the next. Let's take a look at some of the more common PCB layout rules of thumb and see how they apply to the boards we are currently laying out. Start with a Plan Something that you probably won't ever find printed in a company procedure or a PCB design tutorial is the importance of having a plan before you start. Many layout designers have been known to plunge right into a new design, without first considering all the rami- fications of what they are doing. is can lead to routing frustrations and eventual changes PCB Layout Rules of Thumb for Consideration Figure 1: The first rule of thumb is that a PCB layout should start with a detailed plan to avoid problems completing the design.