I am planning to eliminate buffer driver while interfacng INA333 & AD7988-1 (successive approximation type) for sensor bridge with required update rate upto 1KHz. The bridge output is DC and is ratiometric to ADC reference (Antialiasing filter is included). By default, application notes suggest to add buffer to drive SAR ADC but since input is DC and DC performance of ADC's are less sensitive to input impedance, will there be risk with INA333 driving ADC directly with 1KHz update rate?
We are working on this and will get back with you shortly.
Precision Analog Applications
By slowing down the data rate to 1ksps we calculated the new acquisition time to be 990.5us. This corresponds to a required driver BW of ~7.6kHz, which is within the BW of the INA333 given the gain is <~50V/V. We recommend placing an RC filter between the INA333 and the ADC as discussed in the following article series:
If you have any issues with the current ADC, we recommend considering the ADC161S626.
We hope this helps!
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