Data Sheet
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.
110
108
TA = 25°C
106
104
102
100
98
96
94
92
90
0
5
10
15
20
25
30
DAYS
Figure 44. Battery Operating Life Depletion
AD5243/AD5248
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.
Rev. B | Page 15 of 20