APPLICATIONS INFORMATION

The MiniPots are intended for circuits requiring digitally controlled adjustable resistance, such as LCD contrast control, where voltage biasing adjusts the display contrast.

Alternative Positive LCD Bias Control

An op amp can be used to provide buffering and gain on the output of the CAT5110/CAT5125. This can be done by connecting the wiper output to the positive input of a noninverting op amp as shown in Figure 3. Figure 4 shows a similar circuit for the CAT5119/ CAT5124.

Adjustable Gain

Figure 5 shows how to use either a variable resistor or a potentiometer to digitally adjust the gain of a noninverting op amp configuration, by connecting the Minipot in series with a resistor to ground. The MiniPots have a low 5ppm/ºC ratiometric tempco that allows for a very stable adjustable gain configuration over temperature.

Figure 3. Positive LCD Bias Control Figure 4. Positive LCD Bias Control

Figure 5a. Adjustable Gain Circuit Figure 5b. Adjustable Gain Circuit

Doc. No. MD-2120 Rev. J

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© Catalyst Semiconductor, Inc.

Characteristics subject to change without notice