AD5246

Rev. 0 | Page 15 of 20

CONSTANT BIAS TO RETAIN RESISTANCE SETTING

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.

DAYS

0

90%

92%

94%

96%

510

15

98%

100%

102%

104%

106%

108%

110%

20

25

30

Figure 35. Battery Operating Life Depletion

This demonstrates that constantly biasing the pot is not an

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.

Figure 36. AD5246 Evaluation Board Software