I am doing transient analysis. I need to change the temperature during my transient analysis.
I use the Temp under 'OPTIONS' and use pwl function to change its value.
But during simulation it gave me errors. Anyone plz help me how to solve this?

 

You solve it by reading what it is telling you: "Temperature can only be swept by sweeping the 'temp' variable directly."

 

Temperature dependencies are calculated once at the beginning of a transient simulation. When SPICE was developed, computers didn't have anywhere near the processing power to redo these computations dynamically as the simulation ran. That's a legacy that we still live with today with most simulators.

One option, but it is likely too much work, is to run temperature sweeps on the devices you want to simulate dynamic temperature behavior for and then implement behavioral models in which temperature is replaced with some other variable and then vary that variable over time they way you would temperature.