The CAT5110/5118/5119/5123/5124/5125 consist of a fixed resistor and a wiper contact with 32?tap points that are digitally controlled through a 2-wire up/down serial interface. Three end-to-end resistance values are available： 10 k， 50 k and 100 k. The CAT5110/5125 is designed to operate as a potentiometer. In this configuration， the low terminal of the resistor array is connected to ground （pin 2）。 The CAT5118/5123 performs as a variable resistor. In this device， the wiper terminal and high terminal of the resistor array are connected at pin 5. The CAT5119/5124 is a similar variable resistor， except the low terminal is connected to pin 5. D。

　　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 9. Figure 10 shows a similar circuit for the CAT5119/CAT5124.