How to do ac simulation in cadence for an opamp?

[rockycheng]

opamp simulation in cadence spectre

I heard about some tricky ways, using large resistance and capacitance to form a feedback. But I'm not quite sure. Could anyone tell me the exact way? Thanks a lot.

Regards
rockycheng

 

[suria3]

how to do ac simulaton in cadence?

Hi,

Can you brief in detail what AC analysis you want to run. If you say large resistor and caps, that could be to have lower cutoff frequency, some kind of filter termination. So, im not sure what you are talking about. Please be specific.

Thanks,
Suria

 

[nxing]

ac open loop cadence

post the circuit out, maybe we can help.

 

[rockycheng]

ho to do ac simulation in cadence

Thank you for the reply! It is just a normal cascode OTA. I've tried the following test circuit to see the gain vs. frequency transfer function. The result is just the same without the feedback. Would anyone tell me why and when to use the circuit like this? Or it is useless at all?

 

[skal81]

howto ac analysis cadence

You can maybe refer to the following PDF. It's a general testbench method.
Hope it helps.

 

[flushrat]

simulation of op amp in cadence

when calculating the operating point, the R connect output and negetive input,
when doing AC analusis, the C short the negetive inout to ground.
This is the method to simulate open loop characters.

Thank you for the reply! It is just a normal cascode OTA. I've tried the following test circuit to see the gain vs. frequency transfer function. The result is just the same without the feedback. Would anyone tell me why and when to use the circuit like this? Or it is useless at all?

 

[zhaoshibin]

op amp ac simulation

You can find some guideline in the book of " the designer's guide of spice and spectre"

 

[paladinzlp]

ota simulation cadence

You can do step responce simulation.

 

[najhannur]

cadence ac simulation

Hi

You can try this.. I found it and it helps me to understand how to test Op Amp

 

[dozy_walia]

how to do ac simulation of op amp in cadence

How to do ac simulation in cadence for an opamp?
Answer: Analog Artist -> Analysys > AC > Enable.
You can try different values for diffeent responses.
Hope it helps!

 

[haoshs]

how to do ac simulation

you can find the reason in the book ' CMOS analog circuit design' by Allen(chapter 6)

 

[gavinchiu]

op-amp ac simulation cadence

I need such kind document.

 

[paley]

ac simulation in cadence

T=RC must vrey large

 

[neo79]

op amp simulation in cadence

search google with keywords: rinco mora, he has a few pdf pages explainging how to do loop breaking ac simulation. extremely good. you will get full understanding from it.

 

[crossbow_123]

spectre op amp ac simulation

I heard about some tricky ways, using large resistance and capacitance to form a feedback. But I'm not quite sure. Could anyone tell me the exact way? Thanks a lot.

Regards
rockycheng

Using spectre

 

[stormknight]

cadence opamp circuit spectre

guide to spice & spectre

 

[shake2004]

designer's guide spice and spectre.you will google some lab notes.

 

[xwj623]

T=RC must vrey large

good. i meet the same Q.

 

[Ben_edaboard]

you could use iprobe and stb

 

[dragonsword]

the stb is interesting! thanks a lot