Issue link: https://iconnect007.uberflip.com/i/1114420
50 DESIGN007 MAGAZINE I MAY 2019 safely out of trouble. Yet, even today, some de- signers won't use their design rules and con- straints to their fullest extent. I wonder if some designers don't want to take the time to fill out all of those annoying DRC details. It is true that you can jump right in and start routing traces that way, but at what cost? Having to re-spin a design because of manufacturing errors that could have been avoided by using your design rules can be an expensive mistake. Maybe some designers don't understand how incredibly helpful these rules can be. I think that most everyone would agree that setting up the basic trace width and clearance rules can make our job as PCB designers much easier. But with all of the DRC capabilities that are in most PCB design systems, you can set up all kinds of rules and constraints for many dif- ferent objects beside standard trace and space rules. There are rules for text, holes, and dif- ferent kinds of inclusion or keepout zones. You can also set up specialized constraints for mi- crovias, power plane connections, and com- ponent heights. Then, there are whole realms of advanced rules and constraints, including high-speed design rules, manufacturing rules, and much, much more. Setting up the rules will take some time; that is true. Fortunately, many PCB design systems feature helpful tools, such as spreadsheet style design rules and constraints menus that al- low you to import and export your rules from either the schematic or the layout with ease. Many design departments store their design rules like library parts so that their designers can quickly import a basic set of rules that have been saved for specific design technol- ogy. Once in place, those basic rules can then be modified and enhanced for the particular design, and then saved out again for the next person to use. Pay it forward. Anything that we can do to help reduce design time is well worth it. Conclusion The bottom line is this; just as traffic rules are in place to protect us, so are PCB design rules. For those who ignore any of these rules, there could be some expensive consequences waiting for them at the end of the road. On the flip side, there are enormous benefits when working within rules and constraints. Teenage drivers will certainly enjoy the privileges of driving, I enjoyed avoiding the flames of the Mt. Shasta fire, and PCB designers will enjoy designing the latest technologies, knowing that the full range of their online DRCs will keep them from making time-consuming and costly mistakes. DESIGN007 Tim Haag is a PCB design consultant based in Portland, Oregon. To read past columns or contact Haag, click here. Figure 1: Driver's view of the Mt. Shasta forest fire in the fall of 2018.