As we run simulation of a circuit,we see from spectre or else that with temperature increasing,the performance of the circuit degraded.Like the speed becomes slower.
But what the exact reason for this phenomenon?
I can imagine two reasons,one is that the mobility is decreasing while temperature increasing, the other is that the R has positive TC so its value becoming large and the RC constant has increased account for speed down.
I wonder whether one of my option is right?
And what about the influence on the gain with temperature?I think gm is aslo decreaed with mobility reduction,right?

Best regards
urian

You need to show your circuit if you want a meaningful answer.

But... in general analog circuits go faster with higher current and higher mobility (which both translate to higher gm).

Higher temperature decreases mobility and that would normally decreases speed. Similarly, if your circuit is biased with a positive TC resistor the speed would also tend to decrease as temp increases.

The general fix is to use a beta-multiplier bias circuit to keep the gm of the important devices constant over temperature by supplying a current that is roughly proportional to absolute temperature (aka PTAT).

rg

hi,
please show me some results man..i didn't get any such type of result till now. how you are biasing you op amps in all stages..i guess you have to use at least one resister. isn't it?

Thanks.