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The Shaughnessy Report: Showing Some Constraint

When we first decided to cover strategies for setting PCB design constraints, one designer we spoke with said, “They’re not really constraints; they’re more like guardrails that prevent your design from going off a cliff.”

It’s no wonder. The entire PCB is a product of constraints, and the design cycle is full of trade-offs that can each lead to more trade-offs. The guiding constraints for most designs are performance, manufacturability, and cost, and every decision made in the design cycle tends to increase or decrease one of these.

Everything on the PCB can be a design constraint, depending on the final product. Component and drill sizes, traces and spaces, material requirements, microvias, test, signal and power integrity, thermal management needs, fabricator limitations, and supply chain uncertainties are just a few design constraints that can make or break your design. This almost endless list can also include FCC, FDA, UL, and ITAR requirements.

Much of the information needed for a successful design constraint strategy is found in IPC-6012, and EDA tool companies have made setting design constraints as intuitive as possible. But creating a robust strategy that balances these electrical and manufacturing trade-offs requires a level of knowledge that can take decades to develop.

Fortunately, our expert contributors, many of them instructors, have this level of knowledge. This month, we focus on design constraints—the requirements, challenges, and best practices for setting up the right constraint strategy.

We start this month's Design007 Magazine with a conversation with Kris Moyer, who explains how to develop a design constraint plan, and the role that IPC standards can play here. Columnist Barry Olney discusses how to optimize design constraints when pushing technological boundaries. Fil Arzola reflects on the “olden days” when constraint management wasn’t necessary, and why today’s design engineers must embrace it to succeed. John Watson explains his approach to constraint management and why “just because you can, doesn’t mean you should” is not a good motto for designers.

Stephen Chavez shares his views on constraint strategies, and he discusses why design constraints are similar to city ordinances. Columnist Martyn Gaudion lays out his high-speed constraint ideas for the next generation of engineers. Columnist Vern Solberg focuses on basic PCB planning criteria, and columnist Kelly Dack discusses the “5 Ws” of constraints. We also have a column by Matt Stevenson and an article by Anaya Vardya.

I hope you all are enjoying the summer. See you next month.

This column originally appeared in the July 2025 issue of Design007 Magazine.