AD5243 datasheet(15/20 Pages) AD

15 / 20 page

Data Sheet

AD5243/AD5248

Rev. C | Page 15 of 20

CONSTANT BIAS TO RETAIN RESISTANCE SETTING

For users who desire nonvolatility but cannot justify the addi-

tional cost of an EEMEM, the AD5243/AD5248 can be considered

low cost alternatives by maintaining a constant bias to retain the

wiper setting. The AD5243/AD5248 are designed specifically for

low power applications, allowing low power consumption even

in battery-operated systems. The graph in Figure 44 demonstrates

the power consumption from a 3.4 V, 450 mAhr Li-Ion cell phone

battery connected to the AD5243/AD5248. The measurement

over time shows that the device draws approximately 1.3 µA

and consumes negligible power. Over a course of 30 days, the

battery is depleted by less than 2%, the majority of which is due

to the intrinsic leakage current of the battery itself.

DAYS

100

102

104

106

108

110

TA = 25°C

Figure 44. Battery Operating Life Depletion

This demonstrates that constantly biasing the potentiometer

can be a practical approach. Most portable devices do not

require the removal of batteries for the purpose of charging.

Although the resistance setting of the AD5243/AD5248 is lost

when the battery needs replacement, such events occur rather

infrequently such that this inconvenience is justified by the

lower cost and smaller size offered by the AD5243/AD5248. If

total power is lost, the user should be provided with a means to

adjust the setting accordingly.

AD5243 Datasheet(PDF) 15 Page - Analog Devices