some problems about Sample and hold circuit

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winsonpku

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now,i designed a Sample and hold circuit for a pipeline ADC
i want to know how to evaluate its performance.
maybe the SNR is a specification
but how to simulate it?
who can tell me the details
any answer is welcome
thanks
 

some problems about Samle and hold circuit

use spectre in ic50
.pss
.pac
.pnoise

Also pay attention to the information about the clock
 

Re: some problems about Samle and hold circuit

how can do these simulations in hspice?
and how can choose sampling capacitor?


sunking said:
use spectre in ic50
.pss
.pac
.pnoise

Also pay attention to the information about the clock
Click to expand...
 

Re: some problems about Samle and hold circuit

Some of the most important specs for S/H in pipeline ADC include SNR and THD. You can simulate these parameters in HSPICE, without using spectreRF features. To do this, you need to calculate the kT/C noise and OTA noise contribution carefully due to inherent alias. Other than this, the THD performance can be simply measured by perform FFT on the transient simulation strobed data points when you apply a sinusoidal input.
 

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    winsonpku

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Re: some problems about Samle and hold circuit

so you mean by performing the FFT to evaluate the THD
then how to simulate the SNR?

 

some problems about Samle and hold circuit

u can also get snr value in frequency domain.
don't include hamonic power.
 

some problems about Samle and hold circuit

hspice is not a good tool for S/H in design ADC, esp. for SNR and THD.
Maybe you can try hspiceRF tool
 

Re: some problems about Samle and hold circuit

how to do this?
can you tell me the details?

swicap said:
u can also get snr value in frequency domain.
don't include hamonic power.
Click to expand...
 

hi all,can any one tell me which chip may replace LF198 because this is not avaliable for me
 

Re: some problems about Samle and hold circuit

maybe you need a scirpt to add all the pin's power except harmonic~
also use tools, like the spiceexplorer(a small waveform software), it supply the function of FFT/DFT and SNR,SFDR calculation

 

almottleb said:
hi all,can any one tell me which chip may replace LF198 because this is not avaliable for me
Click to expand...
 

How about using matlab? I often use this tool. But sometimes the result is so good that I am not very sure.
 

You should use spectreRf for such simulation.
 

for noise analysis such as SNR, you should use RF simulator. for distortion analysis, just general trans simulation and do FFT is enough.
 

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