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AD7608 Analog Filter Pass Band

Question asked by jonathanj on Sep 6, 2011
Latest reply on Sep 9, 2011 by clairec



I am interesting in a 8-channel simultaneous SAR 18 bit ADC working at the rate of the AD7608 : 200Ksps


Looking at the Analog Input 2nd order LPF, it is mentionned that the pass band is about 20KHz at +-10V range and about 14KHz at +-5V range.


we are looking for a bandwith of close to the nyquist frequency 100Khz (if sampling at 200Khz)


1 - It seems that the analog filter could not be bypassed as the digital filter can be, am I right?

2 - the data Bandwith of the AD7608 ADC is about 20Khz (+-10V range ) no matter if the sampling rate is increased, am I right?

     oversampling higer that 40Khz will only make the SNR better but won't increase the data BW.

3 - Is there a similar 18bit ADC without that analog filter feature, or alternatively, could we change the cut-off frequency of that such filter?


Thanks for your help.