AD5246
CONSTANT BIAS TO RETAIN RESISTANCE SETTING
This demonstrates that constantly biasing the pot is not an
For users who desire nonvolatility but cannot justify the addi-
tional cost for the EEMEM, the AD5246 may be considered as a
low cost alternative by maintaining a constant bias to retain the
wiper setting. The AD5246 was designed specifically with low
power in mind, which allows low power consumption even in
battery-operated systems. The graph in Figure 35 demonstrates
the power consumption from a 3.4 V 450 mAhr Li-ion cell
phone battery, which is connected to the AD5246. The measure-
ment over time shows that the device draws approximately
1.3 µA and consumes negligible power. Over a course of 30
days, the battery was depleted by less than 2%, the majority of
which is due to the intrinsic leakage current of the battery itself.
impractical approach. Most portable devices do not require the
removal of batteries for the purpose of charging. Although the
resistance setting of the AD5246 will be 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 AD5246. If and when total power is lost, the
user should be provided with a means to adjust the setting
accordingly.
EVALUATION BOARD
An evaluation board, along with all necessary software, is
available to program the AD5246 from any PC running
Windows® 98, Windows 2000, or Windows XP®. The graphical
user interface, as shown in Figure 36 is straightforward and easy
to use. More detailed information is available in the user
manual, which comes with the board.
110%
108%
T
= 25°C
A
106%
104%
102%
100%
98%
96%
94%
92%
90%
0
5
10
15
20
25
30
DAYS
Figure 35. Battery Operating Life Depletion
Figure 36. AD5246 Evaluation Board Software
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