Figure 6. Plot of Figure 5 circuit of reference voltage output versus pot A and pot B (32-by-32

taps used instead of 256-by-256 taps for clarity)

Summary

Three circuit topologies were presented that provide the capability to digitally adjust the

MAX6160's output voltage. The first topology provides the capability to coarsely adjust the

output voltage over a wide range using a 32- or 256-tap digital pot. The second topology is

capable of finely adjusting the output voltage about a single output voltage by using two fixed

resistors and a 32-tap digital pot. The third topology can finely tune the output voltage over a

wide range by using a dual, 256-tap digital pot. Table 2 summarizes the initial accuracy for each

circuit presented.

Table 2. Summary of Initial Accuracy

Digital Pot Features

Output

Voltage

MAX5462

32T, 100

Kilohms

MAX5401

256T, 100

Kilohms

MAX5160

32T, 50

Kilohms,

Two

Resistors

MAX5415

256T, 100

Kilohms,

Dual

2.048V

5%

0.6%

0.5%

0.06%

2.500V

7%

0.8%

0.5%

0.03%

4.096V

11%

1.3%

0.5%

0.08%