Spice model for a heatsink/mounting hole/test-point/connector pin - devices with one or no connection points - using Altium simulator

Question

I am setting up a simulation model in Altium with SPICE models and have no idea how to provide a model for a single connection device (connector pin, test-point) or a no-connection device like a heatsink or mounting hole. Altium is saying these parts have no model and the auto-search has not linked anything to them.

I've searched and come up with things like a model with large resistances to ground or components to represent parasitic values, etc., but for a single point connection, how does that work? Also, what if the device has no pins at all, like a heatsink?

An alternative is to tell Altium to ignore them. It may be possible to draw compile masks over them, but there must be a better way, and my circuit has around 150 of them.

So please can I ask what experienced users of SPICE do in this case?

Many thanks in advance.

Answer 1

If you need a project with no warnings or errors, -- well, you can still just disable the relevant errors entirely -- but one way would be to make a one-pin model to global ground (0).

.SUBCKT DUMMY 1
RD 1 0 1e12
.ENDS

something like that would do I guess. Maybe an R isn't even necessary? I'm not actually sure what a valid minimal .SUBCKT is.

Personally, I just ignore the warning. If there is no model attached, there is no entry in the netlist.

Yet another method could be: use one schematic sheet common to two projects, which contains just the active circuitry in question. The upper-level sheet contains non-simulation and mechanical components (and the rest of the project) for the physical PrjPcb, and maybe nothing, or maybe simulation harness stuff (virtual components like simulation sources, function blocks, etc.).

Or for that matter, in this way you can divide anything that you just don't need to simulate, or simulate all at once -- you could divide one project into multiple subcircuits this way, simulated in multiple different projects.

Put another way: this is the schematic equivalent of using one e.g. *.c module in an overall project, while also running the same file in a separate test suite.