LTC2380-24 Figure11b condition

Hi

In LTC2380-24 datasheet, 

Which setting is used in LTC2380? (How ns is acquisition time?)

With Precision ADC Driver Tool,

・ADC Driver is LTC6363(short circuit current is near LTC6362).

・fin=2kHz Rext=35.7Ω Cext=6.8nF Sample Rate =2MSPS Vref=5V

 but input settling time is not enough.(I tried other ADC driver (ADA4945) and some revised but it's not enough (8.13mV error))

Best regards 

Thank you very much.