Getting Our ‘Fil’ of Design Constraint Techniques

Estimated reading time: 1 minute

Setting design constraints is one of the most critical parts of the PCB design process. The PCB designer must balance performance, manufacturability, and cost while addressing issues such as component function, signal integrity, thermal management, and EDA tool idiosyncrasies.

Filbert Arzola is a principal electrical engineer at Raytheon SAS and an instructor who teaches one of the few classes (that I know of) that focuses on setting design constraints. I asked Fil to share his thoughts on design constraints: the factors involved, the various trade-offs, and his best practices for optimizing constraints for your particular design. As Fil says, “Everything about a PCB is a constraint.”

What sort of pre-layout analysis should be performed before you begin setting constraints?

Filbert Arzola: When starting a new PCB board design, one must set up initial routing and clearance constraint settings to enable a good start to engineer your board design. However, one must first review and settle on the initial mechanical model that will house your board design. I highly advise every PCB board engineer to fully understand and confirm the mechanical aspects of the housing, including the outline, the amount and size of the mounting hole clearances, the type and size of the bolt and washer hardware, and most of all, if there are any 3D interferences. A nice DXF file that details all this information completes the electronic model to pre-analyze the mechanical aspect of the board design. One must understand why we constrain our designs and what doing so will give us in return. Having a solid, well-designed, and engineered mechanical model is a must to constrain a successful PCB model database.

To continue reading this interview, which originally appeared in the July 2025 issue of Design007 Magazine, click here.