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16 DESIGN007 MAGAZINE I JULY 2025 Entry-level EDA tools often depend on the expertise of PCB designers to identify potential issues as they emerge during the design process. However, today's complex designs necessitate a more constraint-driven, correct-by-construction approach. Once the rules are defined, downstream tools will adhere to them and validate compliance through various Design Rule Checkers (DRCs). For managing a high volume of constraints, a spread- sheet format proves to be more efficient, allowing for sorting, filtering, and duplicating constraints. Effective constraint management enhances syn- chronization between schematic and layout, facil- itates streamlined access to pertinent PCB data, reduces errors stemming from data integrity issues, and encourages increased reuse of PCB data. Key Points • Each design necessitates a specific set of constraints based on the technologies employed. • The reuse of constraints is also restricted by net and group naming conventions. Consis- tency in naming makes the porting process much smoother. • Develop high-speed design constraints based on pre-layout simulations. • By integrating a constraint-driven methodol- ogy, designers can streamline the feedback loop between simulation and layout. B E YO N D D ES I G N • Adhering to IPC standards ensures that your designs are optimized for both manufactur- ability and mass production. • Designers must identify the sensitive compo- nents within the circuit and recognize potential issues arising from coupling and reflections. • There is no one-size-fits-all solution when it comes to design constraints. • Once the rules are defined, downstream tools will adhere to them and validate compli- ance through various DRCs. DESIGN007 Resources • Beyond Design by Barry Olney: "High-Speed PCB Design Constraints," "The Fundamental Rules of High-Speed PCB Design Part 1" • "Why impose design constraints," by Steve Hughes, Siemens EDA Barry Olney is managing director of In-Circuit Design Pty Ltd (iCD), Australia, a PCB design service bureau that specializes in board-level simulation. The company developed the iCD Design Integrity software incorporating the iCD Stackup, PDN, and CPW Planner. The software can be downloaded at www.icd.com.au. To read past columns, click here.