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Simulators >> Circuit Simulators >> how to get SNR for delta-sigma DAC
https://designers-guide.org/forum/YaBB.pl?num=1599972455

Message started by sycamore on Sep 12^th, 2020, 9:47pm

Title: how to get SNR for delta-sigma DAC
Post by sycamore on Sep 12^th, 2020, 9:47pm

Hello everyone! Lately I have simulated fully differential OTA with chopper stablization circuits. I need to get SNR of output waveforms. The first methd of getting SNR is that I simulate it by tran noise simulation and I can get the output waveforms, after FFT transforming, I can read the result of SNR. The second way is PSS simulation. And I can get the spectrum of noise then by some mathematical calculation I can get the SNR. But these two ways attain two different results. I don't know which way of simulation is accurate. I hope that I can get yours answers. Thank you!

Title: Re: how to get SNR for delta-sigma DAC
Post by sheldon on Oct 22^nd, 2020, 9:38pm

Sycamore,

In general, Delta-Sigma DACs do not have periodic steady-states. How
do you force a steady-state?

Sheldon

Title: Re: how to get SNR for delta-sigma DAC
Post by sycamore on Oct 23^rd, 2020, 1:34am

Hi, Sheldon!
Thanks for your reply. I appreciate your time. At present, I just consider the performance of reconstruction filter. I think that the fully differential OTA with chopper stablization can be stable after several microseconds when the beating frequency of PSS and PNOISE simulation interface is chopper frequency.
Do you mean that the second way to get SNR is not accurate? If so, how can I simulate noise performance of reconstruction filter and get the SNR?