# SPICE IC model in-circuit power dissipation

I'm looking into a way to calculate the power dissipation of any arbitrary IC in circuit on SPICE. I eventually hope to create simple scripts that can list power dissipation of the device and potentially raise a flag if the device is over our de-rated maximums. I've been looking online and can't find any concrete methods to do so.

How do I model the power dissipation of an IC in SPICE?

• Can't you just multiply the supply voltage by the supply current? What exactly do you mean by "raise a flag"? – Elliot Alderson Dec 19 '19 at 18:38
• I meant as in alerting us that a part is going over rated value, that was just context nothing to do with the actual problem sorry. My issue with that is that the supply is going to be shared with other components, and the power generated by it isn't going to be consumed only by the IC in question – Jaywalk Dec 19 '19 at 18:41
• You can always add a 0V source in series with the component of interest and use the current through that source. I feel like there are details you haven't told us. What kinds of models are you using for the ICs? Which SPICE? – Elliot Alderson Dec 19 '19 at 18:56
• Spice3, for IC's I'm currently looking at op amps, but would like to model other parts as well eventually; any arbitrary IC. I'm sorry it sounds a little vague, I'm sort of in the research phase on this. Would looking at the currents going into the IC's multiplied by the supply voltage (minus any loading) be a good measurement of the power dissipation? I ask because adding 0V sources to all the circuits would make it look ridiculous. – Jaywalk Dec 19 '19 at 19:12
• OK, I didn't know you were worried about "looks". – Elliot Alderson Dec 19 '19 at 19:20

• @VoltageSpike Just a side note: try to avoid Laplace in .TRAN, they can be dreadful. Whenever you can, replace them with a proper RLC network for infinitely faster and more accurate results. – a concerned citizen Dec 20 '19 at 17:44