Issue link: https://iconnect007.uberflip.com/i/1538269
54 DESIGN007 MAGAZINE I AUGUST 2025 H A P PY 'S T EC H TA L K # 4 2 by H a p py H o l d e n , I - C o n n e ct 0 07 Applying Density Equations to UHDI Design W ith the need for faster speeds, more parts on an assembly, and the trend to make things smaller for portability, the printed circuit design and layout process is both creative and challenging. The process involves "applying the density equation" while considering certain boundary conditions, such as electrical and thermal performance. Unfortunately, many designers don't realize there is a mathemati- cal process to laying out a printed circuit. The density equation below has two parts: the left side, which C o m p o n e nt 's PW B W i r i n g D e m a n d PW B s D e s i g n R u l e s & C o n st r u ct i o n W i r i n g C a p a b i l i t i e s < ▼ F i g u re 1 : P C B w i r i n g c a p a b i l i t y m u st exc e e d t h e re q u i re d w i r i n g d e n s i t y to a c h i eve ro u t i n g . is the component wiring demand, and the right side, which is the substrate wiring capability. 1 Component Wiring Demand Wiring demand is the total connection length required to connect all the parts in a circuit. When you specify an assembly size, you create the wir- ing density in inches per square inch or centime- ters per square cm (Figure 1). Models early in the design planning process can estimate the wiring