Simulation of PCB resistance/impedance

[magic]

I suspect that nothing fitting a reasonable hobby budget exists, but anyway...

I wonder if there are tools for solving things like potential gradients and current density on real world PCB layouts of the sort that would give you headache trying to replace them with lumped components - ground planes, planes with holes and cuts, pours, tracks with more width than length or with variable width, that sort of stuff.

Some sort of brute force finite element analysis or similar method. Feed the PCB design files in, get the heatmaps out.
I see some mentions of high end CAD packages supporting such analyses for high speed digital and RF, but frankly, even DC resistance could be useful.

[mawyatt]

There are some simulators that support this kind of analysis, most are mesh based finite analysis types. We used them for our chips designs, recall they were expensive and under the Cadence Frameworks.

Edit: There was a "Back Annotate" mode where one would bring back into the simulations the various Rs and Cs from the layout, some times even the Ls. These back annotation parameters were setup with limits on how fine the "granularity" to try and keep the simulation times within reason.

IBM had developed Thermal models for devices in the SiGe processes that included 1st and 2nd order effects, vaguely remember proximity parameters as well. These influenced both DC, AC and Transient Analysis results, and were quite involved, requiring enormous amounts of computing power.

Back in the 80~90s we created a number of SPICE based Thermal models for specific devices, that worked in DC and Transient Analysis modes. Much later we were allowed to publish something on this in EDN.

https://www.edn.com/edn-access-08-18-94-spice-runs-thermal-analysi/

Best,

[pointhi]

There is some intial code for KiCad to add DC power integrity simulation. See this branch: https://gitlab.com/pointhi/kicad/-/tree/sparselizard_fem. There is also a bit of documentation how you can build it locally: https://gitlab.com/pointhi/kicad/-/wikis/Sparselizard-branch

See this talk for some additional insights: https://fosdem.org/2022/schedule/event/advanced_sim/