Underconstraining Your Materials? Leave It to the Experts

Estimated reading time: 2 minutes

With traditional laminates now sporting improved resin systems, some OEMs are choosing various flavors of FR-4 instead of high-speed laminates for their high-speed designs—even RF applications. Avoiding overconstraining your materials in high-speed products can lead to considerable cost savings, not to mention a more streamlined trip through fabrication.

But what do designers and design engineers need to know before they start using traditional PCB laminates for RF applications? Raytheon’s Filbert Arzola is a principal electrical engineer, IPC instructor, and a big advocate of setting constraints correctly early in the design cycle. We caught up with him at IPC APEX EXPO when his Professional Development Course on constraints was taking a lunch break.

Andy Shaughnessy: It seemed fitting to talk with you here in Anaheim during your class on constraining your high-speed board correctly. Tell us a little about the class.

Filbert Arzola: Sure. One of the things we've learned is that some high-speed designers have, in the past, put too much focus on materials that had a certain glass weave. We went through so much waste trying to use glass weave at a certain angle. We had so much trouble getting a board done that we've gone to other material types, adding dielectric to them just to make things work better. I learned there are certain kinds of material and FR-4 materials, including one that, even though it's not the best, still gives a good end-product. The end product is what matters.

Kelly Dack: There's no question that consistency in materials, manufacturing, and performance is key. What are the elements of consistency in your opinion?

Arzola: You need to even be able to get the materials, and not just on time. Let's say you call a vendor and say, “I'm going to build these boards six months from now; can you make sure the material is there?” They'll say, “Sure, material availability is okay.” Then they go out and buy the material. But now, six months later, the material may be outdated with respect to the requirements we want to meet, and we can't use that material. So, that's a big deal.

To read this entire conversation, which appeared in the May 2024 issue of Design007 Magazine, click here.