How do i add an external MOSFET thermal Model to SOAtherm-NMOS

Hello cbocatto,

I recommend to completely read this earlier discussion below.

ez.analog.com/.../soatherm-nmos-symbol-missing-in-ltspice-xvii

The values for the RC-networks are in the datasheet.
www.vishay.com/.../sqjq410el_rc.pdf
You could take these numbers and create something similar what I have shown in my examples.
Normally one simply connect one G-source having the power formula to the input of the RC-ladder network.
I = V(s)*I(s) +V(g)*I(g) + V(d)*I(d)
The output of the RC-ladder will be connected to a V-source with Tambient or Tcase.

You could also try to use the thermal subcircuit from the zip-file from Vishay. I wonder why they use 9 G-sources with the same power formula in this subcircuit.

Please also read the AN609.
www.vishay.com/.../73554.pdf

Helmut

Hello cbocatto,

I have now specfically worked on your example.

I firstly tried with the thermal model SQJQ410EL_PS_RC, but I couldn't find any signal inside the subcircuit which looked as expected.

I made then my own thermal measurement circuits with the model parameters from Vishay - sqjq410el_rc.pdf. The TANK and the FILTER models behaves very similar. Normally you will need only one of the four models.
Junction to Ambient Tank Model
Junction to Ambient Filter Model
Junction to Case Tank Model
Junction to Case Filter Model

Helmut

SOAtherm_SQJQ41_Test1.zip

Helmuts,

This is what  i was looking for, Thank you!

I also took a look at the post that you pointed me to and it is very informative.

I appreciate your help on this question  and the overall forum!

Can you explain what's mean the IC1?

IC1 is a parameter that's set at the top level of the subckt line, and used in the sub circuit.

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