The AD5231/AD5232/AD5233 family offers a single/dual-/quad-channel, digitally controlled variable resistor (VR) with 1024/256/64 position resolutions, respectively. These devices perform the same electronic adjustment functions as potentiometers or variable resistors. The multifunctionality of the AD523X is programmable through the microcontroller, allowing multiple modes of operation and adjustment. The RDAC register can be loaded directly into the microcontroller with a predetermined setting in the direct programming mode. Another key operating mode allows the RDAC register to be refreshed with the settings previously stored in the EEMEM. When the RDAC register is changed to establish a new wiper position, the set value can be executed to save the EEMEM to the EEMEM operation. Once the settings are saved in the EEMEM register these values will be automatically transferred to the RDAC register to set the system power wiper position. This operation is enabled by internal preset strobes and presets can also be accessed externally. The basic mode of adjustment is the increment and decrement commands control the wiper position setting (RDAC) register. The internal scratchpad of the RDAC register can be moved up or down, a nominal terminal step resistor between terminals A - and - B. This linearly varies a position segment of the wiper-to-terminal resistance (RWB) of the device to the terminal-to-terminal resistance (RAB) of the device. For tap setting, left/right exponential/logarithmic change shift command adjustment, available in +/- 6dB steps, very useful for audible and visual alarm applications. The AD523X is available in an ultra-thin TSSOP package. All parts are guaranteed to operate over the extended industrial temperature range of -40°C to +85°C.