Datasheet MAX5527, MAX5528, MAX5529 (Maxim) - 10

One-Time Programmable, Linear-Taper Digital Potentiometers
5V 5V H 30V 30V W MAX5527 V V OUT OUT H MAX5528 L MAX5529 MAX5527 MAX5528 W MAX5529 L Figure 7. Positive LCD Bias Control Using a Voltage-Divider Figure 8. Positive LCD Bias Control Using a Variable Resistor +5V W L 5V VIN VIN H V0 REF R3 C V OUT OUT H MAX6160 R1 W MAX5527 ADJ MAX5528 R GND 2 MAX5529 R1 L H
MAX5527/MAX5528/MAX5529
MAX5527 R2 MAX5528 100kΩ W V0 = 1.23V x FOR THE MAX5527 R2(kΩ) MAX5529 50kΩ V FOR THE MAX5528 L 0 = 1.23V x R2(kΩ) 10kΩ V0 = 1.23V x FOR THE MAX5529 R2(kΩ) Figure 9. Programmable Filter Figure 10. Adjustable Voltage Reference
Applications Information Programmable Filter
Figure 9 shows the configuration for a 1st-order pro- Use the MAX5527/MAX5528/MAX5529 in applications grammable filter. The gain of the filter is adjusted by requiring digitally controlled adjustable resistance, R2, and the cutoff frequency is adjusted by R3. Use the such as LCD contrast control where voltage biasing following equations to calculate the gain (G), and the adjusts the display contrast, or for programmable filters -3dB cutoff frequency (f with adjustable gain and/or cutoff frequency. C), only up to frequencies one decade below the wiper -3dB bandwidth.
Positive LCD Bias Control
R1 Figures 7 and 8 show an application where the voltage- G = 1 + R2 divider or variable resistor is used to make an adjustable, positive LCD bias voltage. The op-amp provides buffer- 1 fC = ing and gain to the resistor-divider network made by the 2π x R3 x C potentiometer (Figure 7), or to a fixed resistor and a variable resistor (Figure 8).
Adjustable Voltage Reference
Figure 10 shows the MAX5527/MAX5528/MAX5529 used as the feedback resistors in an adjustable-voltage reference application.
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