So for SNDR > 60 dB and sampling rate of 200 MHz. That should correspond to a gain error of < 0.1%. How about minimum gain, settling time and unity gain bandwidth? Is there a formula or so?
May be the bandwidth is 5~10 times the sample rate.
The gain is determined by the accuray of the settling of a sampling step. In the meanwhile , the slew rate is also the key parameter for SHA. It is determined by the driving capacitance of the OP.