TC

[ronv]

I read a thread that tried to explain how to change the temperature coefficient of resistors in LT Spice, but couldn't make it work for me. Has anyone done it and if so can you post me an example?

 

[Sceadwian]

Bring up the LTSpice help file, look up resistor, the method for defining the coefficient is shown in black and white. It works like a piece wise linear list of effective coefficient values based on the temperature.

This in and of itself is useless because additional code needs to be written to equate the temperature rise of the resistor over time to the power going through it. This must all be hand coded as far as I'm aware.

 

[ronv]

I see it, but I don't get it. Could you post a screen shot of the window showing 25 ppm?

 

[Sceadwian]

What you're talking about sound like a linear temperature coefficient? But I don't know in relation to what base you mean 25ppm..

What is the specific equation that defines the resistance value in relation to temperature of your resistor?

Again keep in mind, this will do absolutely nothing to your simulations if you don't also add models for the thermal feedback given the package to every model in LTSpice. The additional accuracy of the resistor thermal simulation will mean nothing if it doesn't apply to the rest of the real world thermal considerations which have to be specifically added.

 

[ronv]

Now I get it. No wonder I couldn't make it work.

Thanks!