Can the ADA4528-1 handle large capacitive loads ( > 4.7µF) and drive the reference of a high precision sigma-delta like the AD7173-8?
I do not want to add source resistance between the output of the amp and the input of the reference of the ADC. Will the 200kHz noise from the chopping frequency affect the performance of the converter without a filter? Perhaps a snubber network is advised if the ADA4528 is to be used in this application?
This discussion has been ongoing last week via email and closed.
In summary, below is an excerpt of the email exchange:
" I have sometimes seen customer use ZD amps to buffer a reference output. What they would do is LPF the output of the amp. This however increases the impedance seen at the ADC REF pin (I believe the offset voltage due to current flowing through the resistance can be calibrated out). Also, the ADA4528 cannot drive 4.7uF without any compensation. It can only safely drive up to maybe 200-300pF. So, in this case, having an post RC network serves to isolate the cap load, stabilize the amp and provide filtering.
We haven’t tested any reference buffers with the AD717x family of ADCs for two reasons:
Thanks for the help Vicky!