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chopper stabilized opamp pss simulation problem

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iamxo

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vco pss simulation

from cadence help doc, it is said pss and pnoise can simulate chopper stabilized opamp noise.

so I use this to simulate my design. my design has an on-chip osc.

but when simulating, the pss function (oscillator) doesn't converge well, it often fails.

if I remove the osc circuit, and add an ideal clock, then the pss function works.

so, if I don't want to remove the osc circuit, and I want to simulate noise , how can I do with it ?

thanks all.

My osc frequency is low 100kHz, and the pss function often gets the fundamental frequency away from 100kHz, such as 46kHz, 60kHz.
 

safwatonline

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the oscillator option is for real oscillator circuits which is not ur case, so u need to unselect it and put ur own clock generation model
 

iamxo

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safwatonline said:
the oscillator option is for real oscillator circuits which is not ur case, so u need to unselect it and put ur own clock generation model

but my circuit has an osc part, if I unselect the oscillator option, how did pss do with the circuit?
 

safwatonline

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what do u mean by osc part? do u have something like ring osc. or vco ?
 

iamxo

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safwatonline said:
what do u mean by osc part? do u have something like ring osc. or vco ?

yeah, My circuit has a Gm-C oscillator, it supplies the clock signal. so, when I do pss simulation, I select the "oscillator" option, then it doesn't converges always, just like what I said before.
 

venky442

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the oscillator option is for real oscillator circuits which is not ur case, so u need to unselect it and put ur own clock generation model
 

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