the AD7190 data sheet Table 22 states 5 R-C-combinations for unbuffered operation.
I tried to understand the background of the values but they look non-monotonic: The second last entry (1000pF 230Ohms) has a longer time constant than the last entry.
The total attenuation should be the something like
(Cext / Cint) * exp(tmod / RC)
where tmod is a fraction of the modulator cycle (3,2us), isn't it?
It would be helpful to get some information on the reason behind table 22. And information about the behaviour in unbuffered PGA>1 configurations.
What will be the common mode and differential impedance if I use a huge filter capacitor, i.e. 10uF?
Thanks in advance