jeremy_zhu
Member level 2
comparator of SAR ADC
hi,
i designed a comparator for SAR ADC. the AC simualtion results at a or b
port for ac input is shown below. something pullzed me.
1) for 1k or below , the gain is not enough , so does it mean the ADC can not deal with the <=1K sin signal.
2) the ac characteristic at <=1K caused by the cap. between the preamps? the ac
results of port a will increase by increasing the cap, but unluckly, the bad gain will occure at <=10KHz. how to trade off ?
3) for an ADC, the resolution of the comparator(Vp-Vn) should be <=0.5LSB or 0.25LSB in practical design.
hi,
i designed a comparator for SAR ADC. the AC simualtion results at a or b
port for ac input is shown below. something pullzed me.
1) for 1k or below , the gain is not enough , so does it mean the ADC can not deal with the <=1K sin signal.
2) the ac characteristic at <=1K caused by the cap. between the preamps? the ac
results of port a will increase by increasing the cap, but unluckly, the bad gain will occure at <=10KHz. how to trade off ?
3) for an ADC, the resolution of the comparator(Vp-Vn) should be <=0.5LSB or 0.25LSB in practical design.
