In the recently released book Larry Smith and I wrote, Principles of Power Integrity- Simplified, we offered a spreadsheet to go along with the book, especially the last chapter. You can download your copy of it by clicking here.
We advocate first doing analysis based on simple estimates using rules of thumb, then explore design space using analytical approximations and spreadsheets. Finally, to fill in the details, use a simulation tool.
This is the only real way of practicing safe simulation, which is really about applying rule #9. If you ever encounter one of my students, ask them what rule #9 is and they should immediately say, “Never do a measurement or simulation without first anticipating what you expect to see.” It’s by applying your engineering judgement based on rules of thumb and approximations that you know what to expect to see.
If my student does not give you the correct answer, please let me know and I will get into their University records and retroactively change their grade.
One of the principles we wanted to highlight in our book is how powerful simple models are in accurately predicting performance. You can often answer many of the bog picture questions using simple approximations. When design decisions interact, a spreadsheet is an invaluable tool to explore the tradeoffs.
Larry put together this very cool spreadsheet to take into account how the three typical resonances in a PDN might interact- the Bandini Mountain, the board caps and bulk cap parallel resonance and the VRM and bulk cap parallel resonance.
There’s a lot more to it as well, including the mounting inductance of the capacitors and the package based on their geometry.
It probably won’t mean much without the details outlined on chapter 10 which acts as sort of the user manual and shows a few examples of using this spreadsheet to evaluate a design. But, you can download the spreadsheet and if it tweaks your interest, go ahead and purchase the book. In the pdf version, all the figures are in color. I think you will find a few valuable nuggets that will help you in your next PDN design.