Datasheet

AD7194 Data Sheet

Rev. A | Page 50 of 56

FAST SETTLING MODE (CHOP ENABLED)

Chop can be enabled in the fast settling mode. With chop

enabled, the ADC offset and offset drift are minimized. The

analog input pins are continuously swapped. With the analog

input pins connected in one direction, the settling time of the

sinc filter is allowed and a conversion is recorded. The analog

input pins are then inverted, and another settled conversion

is obtained. Subsequent conversions are averaged so that the

offset is minimized. This continuous swapping of the analog

input pins and the averaging of subsequent conversions means

that the offset drift is also minimized.

Chopping does not change the output data rate. However, the

settling time equals

SETTLE

= 2/f

ADC

Consequently, if chop is enabled, the sinc

filter is selected, FS[9:0]

is set to 6 and averaging by 16 is enabled, and the output data

rate is equal to 42.1 Hz. Therefore, the conversion time equals

1/42.10 Hz or 23.75 ms and the settling time is equal to 47.5 ms.