Op-Amp thermal drift PSPICE

[Draytek]

Hello,

how would be the method to simulate the thermal drift in an op-amp with the SPICE macromodel?

I pretend to simulate the -40 to 85 ºC behaviour of the circuit and i think the op-amp macromodel doesnt have any parameter dependant with the temperature.

 

[crutschow]

The main drift of concern is usually the input offset voltage. This can be simulated by placing a voltage source in series with one of the inputs (either one is fine) with a DC voltage equal the maximum drift specified in the data sheet at the temperature of interest. For example if the drift was specified at ±1µV/°C then you would set the voltage source to (85-25) * 1µV = 60µV for an 85°C simulation. You would use +60µV for one simulation and then -60µV for a second simulation since the drift can be either plus or minus.

 

[Draytek]

So other parameters as input offset current, input bias current are not of concern for thermal drift?