The Magnitude of Stackup Considerations

Estimated reading time: 1 minute

When I was asked to write about stackup creation, I paused at the magnitude of this subject. It is similar to the framework used to pour concrete cement—you need to get the framework right because the framework has such a big impact on the final outcome. Such is the case with shaping the success or failure of our circuits. In writing the newest training manual due out early this year, I observed that the longest chapter in the textbook was dedicated to this subject.

Therefore, I believe it is truly one of the most important and far-reaching subjects in our industry. It was at the heart of my decision to accept an offer to work for Insulectro because it allows me to make a difference in our industry on this subject. Because it’s such a vast topic, I can only scratch the surface in an article, but I hope to scratch it well.

I always like to remind readers to pursue all printed circuit engineering issues from three simultaneous perspectives when we design for X:

1. DFS—Solvability
Place and route dense critical circuitry to define optimal features and implementing constraints that meet three perspectives. Also, mastering an EDA CAD tool is a significant challenge compounded by accelerated development schedules.

2. DFP—Performance
Ensure that all SI, EMI, and thermal performance metrics are met. You can solve a complicated design, then build a perfect bare board, but if the signal energy does not go where it should, you can throw the board in the trash can.

3. DFM—Manufacturability
As our circuits become more advanced so do the challenges associated with building a bare board. With decreased feature sizes, the tolerance window becomes more precise. Therefore, the layout professional must be aware of the manufacturing capabilities and engage with their supply chain at the beginning of layout. The practice of selecting your supply chain once layout is complete is a flawed approach.

To read this entire article, which appeared in the January 2021 issue of Design007, click here.