Issue link: https://iconnect007.uberflip.com/i/1537388
Have you ever sat down to define PCB design con- straints and found yourself staring at a settings win- dow with more checkboxes than a tax form? You're not alone. For many designers—especially those newer to the layout world—the task of setting up design constraints can feel like trying to write a novel in a language you just started learning. It's tempting to jump into the layout tool and start connecting traces, only to hit a wall of design rule checking (DRC) violations and second-guess- ing. That's where we need to pause and reframe. We need to restart with the end in mind. As I have in the past, I suggest using one of my favorite frameworks for this task: the 5 Ws. Let's explore how these five simple questions— who, what, when, where, and why—can lead you toward PCB design constraint clarity and success. Who? Know Your Stakeholders Before entering your first clearance or trace width value, ask yourself: Who are you designing this for? Is this board going to a production fabrication 52 DESIGN007 MAGAZINE I JULY 2025 shop with limited process capabilities? A local pro- totype shop? Will it be assembled by hand or by automated pick-and-place machinery? Stakeholders include more than just an end- use customer. They also encompass PCB fabri- cators, assembly teams, electrical engineers, and even our test engineers. Design constraints should reflect the capabilities and expectations of every- one involved. What? Define the Assembled Product, Not Just the Bare Board You're not just connecting the dots with copper on a laminate material. You're designing a functioning electronic system. What are the electrical require- ments? Will this board assembly operate at high frequency? Will it carry high current? What about creepage and clearance in high-voltage designs? The "what" question zooms out from the PCB itself to the intent of the design. Constraints like trace width, spacing, impedance control, and layer stack-up all start with this question. TA RG E T C O N D I T I O N The 5 Ws of PCB Design Constraints by Kelly Dack , CIT, CID+