Input capacitance (AD8601)

hello,

i would like to know the input capacitance value (common) of the AD8601 amplifier.

If not known, do you have a method to estimate/measure it ?

I would like to put a follower in parallel of a capacitor to measure its voltage charge. But input capacitance of amplifier is measure as a parasitic parameter.

if you have any idea...

thank you

Sebastien