Hi all
Would you mind if we ask ADS7865?
<Question1>
How much is the recommended the value of capacitance at input pin?
Is our following recognition correct?
The capacitor in the RC kickback filter is typically selected to be >10x larger that the sample-and-hold capacitor to provide instantaneous charge transfer to the sample-and hold,
and minimize the effects of charge kickback.
->2pF × 10 = more than 20pF?
The customer's condition is following
Construction : Buffer amp -> RC filter -> ADC input
Input typ : single end
As the background of this question, our customer changes from 2200pF to 220pF at input capacitance.
According to conversion timing, the data decreased, so does it depends on time constant also?
<Question2>
Our customer tested common mode noise test with ±2.0kV/10min.
As the result,it occurred sudden change(decrease the data) phenomenon.
If you have the measure for common mode noise(circuit, layout, choke coil?), could you share us?
The customer would like to know it as reference.
Kind regards,
Hirotaka Matsumoto