How to calculate the value of load capacitor for designing an op amp for pipeline ADC?
I asked the question from Proffessor Razavi and he answered as:

"The minimum value of the capacitors in an MDAC is determined by matching or kT/C noise. The mismatch translates to gain error, which is difficult to calibrate.
If mismatch is not the bottleneck, then kT/C noise is the determining factor. I
doubt the capacitor values will be too small for a 12-bit ADC with a reasonable
LSB size, e.g., 0.25 mV. You need to make sure kT/C is well below LSB^2 / 12."