bandwith of amplifier and delta sigma adc

[sunking]

what the relation between bandwith of amplifier and delta sigma adc ?

such as for a two stage delta sigma, samping freq is 1Mhz, signal band width is 5KHz, SNR is 90dB, then the needed bandwith of the amplifier?

 

[mists]

i think it is ok for the op's bandwidth to satisfy the setting time, such as 0.1%.

 

[Btrend]

refer to this

 

[Chung-Yuan Chen]

Time Constant(ζ)=1/βωt.
For settling to within some accuracy, the settling time need becomes approximately 5ζ within half of system clock(assums taht the duty cycle is 50%). That is just my rough concept.

 

[andy2000a]

I have another problem is ,
if we design a 16 bits delta-signma A/D convert , 1v= full swing level .
if use general A/D we need 1/(2^16) = 15uv accuracy .

for delat Sigma AD the previous analog modulator maybe use mesh(or other topology) , the analog modulator really need 16bit accuracy in one bits comparator or not ?

my friends tell me , deltaSigma A/D 16bit , the 16bit
is average data by digital DSP circuit made it , not by analog comparator
how to define analog comparator accuracy ?

 

[Btrend]

refer to this

 

[xwcwc1234]

To mists ,
" i think it is ok for the op's bandwidth to satisfy the setting time, such as 0.1%". Wht is 0.1% not 0.01% ? How to decide this value ?
.

 

[swicap]

for delta sigma adc,
accuracy of comparator is not very important. The erro induced will be shaped.

Settling erro is important , it contribute to harmonice distortion.
And bw of amp will affect it. refer to wooley's paper and books .
it gives method to calculate it .

 

[xwcwc1234]

To swicap,
Did you have Wooley's book and papers which can calculate the BW and settling time of opamp ? Would you provide the title of papers or books ?