AD5227

Rev. B | Page 14 of 1

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DAYS

CONSTANT BIAS WITH SUPPLY TO

RETAIN RESISTANCE SETTING

2

Users who consider EEMEM potentiometers but cannot justify

the additional cost and programming for their designs can con-

sider constantly biasing the AD5227 with the supply to retain

the resistance setting as shown in Figure 38. The AD5227 is

designed specifically with low power to allow power conservation

even in battery-operated systems. As shown in Figure 39, a

similar low power digital potentiometer is biased with a 3.4 V

450 mA/hour Li-Ion cell phone battery. The measurement shows

that the device drains negligible power. Constantly biasing the

potentiometer is a practical approach because most portable

devices do not require detachable batteries for charging.

Although the resistance setting of the AD5227 is lost when the

battery needs to be replaced, this event occurs so infrequently

that the inconvenience is minimal for most applications.

Figure 39. Battery Consumption Measurement

AD5227

U1

GND

U2

GND

COMPONENT X

U3

GND

COMPONENT Y

GND

SW1

+

–

Figure 38. Constant Bias AD5227 for Resistance Retention