What ADC sampling time to use with Opamp in follower mode? What is Opamp's output impedance in follower mode connected to the ADC?

[Singh.Harjit]

DS12288 doesn't specify the opamp block's output impedance.

Table 67, page 143 has the ADC sampling time for different RAIN but since the opamp's output impedance isn't known, we cannot pick the right sampling time.

[TDK]

The lowest impedance in that table is 100 Ohm. I would expect any opamp in follower mode is going to provide a much much lower effective impedance than this.