Simetrix Model not showing correct thermal characteristics

MSW

Hi,

I want to see the junction temperature of CAS480M12HM3, for a given case temperature at different continuous current levels. Here the model is showing a junction temperature less than the case temperature. Can you please look into this :)

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Bdeboi

Hello,

Thanks for bringing this to my attention. I found a small syntax error in the model with the Schottky diode thermal network specifically.

If you right-click the model and select "view/edit model", you will gain access to the internals of the model. For XD1 and XD2, please change TcH → Tc1, and TcL → Tc2. It should work correctly after this. I will work on correcting this in our libraries.

Thanks,

Brian

MSW

Hi Brian,

I have modified those spice lines you mentioned. However, for a pulsed I_DS profile, i am getting almost receding flat junction temperature.

I expect the junction temperature profile should be like RC charging & discharging.

could this be an model/simulation issue here?

Bdeboi

So, one point to clarify here is that you are looking at the schottky diode temperatures (TjD) and not the MOSFETs (TjQ). I can't see how your simulation is set up, but I'm guessing that the current is flowing through the MOSFETs in your sim. If not I will replicate your sim and take a closer look.

MSW

Hi Brian,

My Mistake, you are right. I am getting the correct profile of junction temperature across TjQ2.

Thanks for the help

AAnders

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