Issue link: https://iconnect007.uberflip.com/i/1514189
72 DESIGN007 MAGAZINE I JANUARY 2024 Heat generation and its management are also of concern. There has been a tendency to pack more components into smaller spaces. disclosure: is will not serve to map the myr- iad concerns facing electronic product design- ers, nor will it detail where all the problems lie. Still, I hope to provide some guidance on important issues facing PCB designers. First, all PCB designs are typically custom and unique; they are one-of-a-kind products. Unfortunately, they are also considered com- modities, making them a "custom commod- ity" (an oxymoron). at said, the designer can try to comply with the needs of a commodity, which is to attempt to keep the dimensions orthogonal, if possible. I trust we have all seen odd-shaped PCBs: round, poly- gonal, and mixtures of the two. Recognize that these boards are pro- duced on rectangular pan- els and that missing mate- rial winds up in the trash. It was paid for, thus the admonishment. Still, it is not uncommon that the board must be designed for a specific product, such as missiles, which are (for ballistic reasons) invariably round. Thus, round circuit boards are designed to fit. In general, when an odd-shaped board is inescapable, it will be necessary to design it for manufacture using a rectan- gular piece of laminate of a standard size, which is what the industry is tooled to do. is is true for both PCB manufacture and assembly. us the designer's odd-shaped design will not be manifest until it is freed from the assembled panel on which it was manufactured. While on the general topic, it is highly advis- able that designers invite themselves (or get invited) to visit their PCB provider before locking down their designs. We all read com- pelling stories about "bleeding edge" high- layer-count PCBs with line and space features of less than 75 µm, but is your vendor capable of such? is brings to mind other concerns relative to circuit performance, including one that has been increasingly important for the past few decades: controlled impedance and signal integrity. Dealing with these companion concerns requires the use of newer soware tools that are designed to help address the chal- lenges involving multiple material and feature design factors, including precision line dimen- sions, laminate dielectric properties makeup, and thickness. Even the "tooth" of the copper foil used can impact results. Heat generation and its manage- ment are also of concern. ere has been a tendency to pack more components into smaller spaces. is impacts the sig- nal integrity concerns as well as the thermal density of the assembly. Increasing ther- mal density has become a higher-order concern for product developers. Thus, heat mitigation has steadily risen in importance because of a known inverse relationship between heat excur- sions and an electronic p r o d u c t 's r e l i a b i l i t y. Fa i l u r e modes include solder joint reliability, plated through-hole integ- rity, and silicon chips' longevity. Again, modeling and analysis tools specific to thermal characterization should be desirably included in the design tool soware suite. I'm sure most of you are aware of the continu- ing evolution of wireless products that are now an indispensable part of our daily lives. With increasing expansion of the electromagnetic spectrum for wireless use, designers must be attentive to the susceptibility of their products to electromagnetic interference (EMI) and its potential to emit electromagnetic radiation that could impact products that surround it.