In spectre, this is not yet (directly) possible. There is an enhancement request for this, and I believe work is underway to support it.

That said, if you have device models which support self-heating, then this should be taken into account.

One way of changing the temperature during a transient would be to run a sequence of transients using the save state/recover state options (see spectre -h tran), and alter to change the temperature. You'd need to ensure that the temperature changed smoothly that you didn't end up with a big discontinuity caused by the operating point changing significantly.

Here's a wildly exaggerated example:

Code:

// temp sweep

parameters vdd_val=3 stoptime=1u

vvdd (vdd 0) vsource type=dc dc=vdd_val
vsin (vdd inp) vsource type=sine ampl=0.1 freq=1M
r1 (inp out) resistor r=1k
r2 (out 0) resistor r=1k tc1=0.1

mytran tran stop=1.2u savefile="end.state" saveperiod=1.2u
alt1 alter param=temp value=30
mytran1 tran stop=2u savefile="end.state" recover="end.state" saveperiod=0.8u
alt2 alter param=temp value=35
mytran2 tran stop=3.1u savefile="end.state" recover="end.state" saveperiod=1.1u 

Note that I used saveperiod instead of savetime to avoid it getting a suffix on the state filename. However, the saveperiod needs to be set to the duration of each transient analysis for this to work...

I did try putting it in a sweep analysis - but this is not supported at the moment (it says that recover can't be used on a tran within a sweep).

By the way, in the above example, it's intentionally not smooth - so I could see it having an effect!

Regards,

Andrew.

I hope the enhancement to Spectre is more general than simply providing the ability to sweep temperature in transient. It should be possible to create an arbitrary temperature profile versus time. That way one could simulate the effect of a thermal shock. Perhaps what is needed is a tsource.

-Ken