How to simulate the change in VT with temperature?

[shaq]

Dear all,

I want to simulate partial(VT) / partial(T) in hspice where VT is thermal voltage of BJT, T is the temperature.

How to do that?

 

[amarendrap14]

you can pump two diffirent current say 1uA and 10uA in two different BJT.
use relation VBE1 -VBE2 = nVt*ln(I1/I2).
so you just nedd to take the difference between two voltage and do a temperature DC sweep.

it should be simple linear line..as expected (Vt=kT/q)

you can take derivative to get dVt/dT.

hope mathimatical funtions are available in the simulator..