question about the simulation condition?

[semitao]

Hi,all.
Who can tell me what is the worst cast simulation condition? The voltage, process variation, temperature. How does this factors combine? Thanks!

 

[pfd001]

worst case is dependant on your spec. Normally, it is ss corner, the lowerest supply voltage, the highest temperature.

 

[semitao]

thanks
can you tell me why is ss corner, lowest supply voltage and highest temperature?

 

[holddreams]

slow nmos,slow pmos.

 

[semitao]

I know it. But why is the ss corner with lowest supply voltage and highest temperature? Why is the ff corner with highest supply voltage not the worst case?

 

[sachinagg77]

The selection of worst case parameters depends on the circuit. For example, some circuits may tend to show worst performance at FF/125C and some may show worst performance at SF/-40C.

So, the simplest way to determine the worst settling for your circuit is to simulate it once for all corners with different temperature and voltage setting and locate the worst case setting.

Later, during the course of design. you can mostly simulate with typical settings and worst case settings.

After you finish the design, you will have to once again simulate for all setting to confirm the performance.

Hope it helps.
With Regards
Sachin

 

[q0w1e2r3]

ss corner:-100c, -10% voltage supply, high dc gain low speed
ff corner:40c ,+10%voltage supply,low voltage supply high speed