The Holy Grail of PCB software: what is the ultimate software solution for PCB design?

Author:Pfeil, Charles

FOR MANY YEARS, I have held the Indiana Jones' perspective that the cup must be a plain clay goblet suitable for a poor carpenter--but maybe not? It will be interesting to find out if they can prove the finding is indeed the One. A grail, of course, is an object or goal sought after for its great significance. The "holy" designation owes to the association with Jesus. So maybe it would be more appropriate to seek the "grail of PCB design software," but that just doesn't sound as good; and besides, "Holy Grail" is often used to name the ultimate fulfilment of any particular endeavor.

Recently an editor asked, "Why is it that PCB placement and routing is not fully automated, and why does it still require so much manual interaction?" Is fully automated place-and-route the Holy Grail of PCB software?

PCB CAD graveyards are filled with failed attempts to attain this goal. The primary factor that impacts the success of the grand software solution is that the component, fabrication and circuit technology are continually evolving, while at the same time adding variety and becoming more complex. This means software that was successful at one time becomes ineffective after a number of years. For example, as surface mount technology was adopted, it became clear very quickly that gridded routing technology could no longer be applied with effective results. This didn't just require a tweaking of the code; it required completely different data structures and new algorithms.

Likewise, the introduction of microvias significantly increased the number of variables to consider. With through vias, the stack-up options consisted of primarily how many signal/plane layers, and their order. Microvias introduce so many options and combinations for via models, layer transition styles, materials and processes that it looks like a menu at P.F Chang's. How do software vendors keep up?

With every new development cycle, we have to allocate resources to both support the technology changes, as well as find ways to solve these challenges with even higher levels of productivity. It was all so simple for many years when we only had through-hole DIP components on an FR-4 through-via board. But then things started to evolve very quickly in the mid '80s. Here is a list of many PCB component, board, and circuit technology changes that have impacted PCB design software over the last 30 years, in no particular order:

* Through-hole components: DIP, PGA.

* Surface mount components...

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