AD8233CB-EBZ User Guide

UG-1016

Rev. 0 | Page 7 of 12

FAST RESTORE

The fast restore function (FR) reduces the duration of otherwise

long settling tails of the high-pass filters. After an abrupt change

that rails the amplifier, such as a leads off condition, the AD8233

automatically adjusts to a higher filter cutoff frequency. This

function allows the AD8233 to recover quickly and, therefore,

take valid measurements soon after reconnecting the electrodes to

the subject. To enable this function, set the S1 switch to the

FR_EN position.

STANDBY OPERATION

The AD8233 includes a shutdown pin (SDN) that further enhances

the flexibility and ease of use in portable applications where power

consumption is critical. To enter standby operation, place the

S3 switch in the SDN position. In this condition, the AD8233

draws less than 1 µA of supply current, offering considerable

power savings. To enter normal operation, place the S3 switch in

the EN position.

During shutdown operation, the AD8233 is not able to maintain

the REFOUT voltage, but it does not drain the REFIN voltage,

thereby maintaining this additional conduction path from the

supply to ground.

When emerging from a shutdown condition, the charge stored

in the capacitors on the high-pass filters can saturate the instru-

mentation amplifier and subsequent stages. The use of the fast

restore feature helps reduce the recovery time and, therefore,

minimize time in power sensitive applications