Description

The AD52521 is a dual-channel, I2C, nonvolatile memory,digitally controlled potentiometer with 256 positions. These devices perform the same electronic adjustmentfunctions as mechanical potentiometers, trimmers, andvariable resistors. The parts’ versatile programmability allowsmultiple modes of operation, including read/write access in theRDAC and EEMEM registers, increment/decrement of resistance,resistance changes in ±6 dB scales, wiper setting readback,and extra EEMEM for storing user-defined information, such asmemory data for other components, look-up table, or systemidentification information.The AD5251/AD5252 allow the host I2C controllers to writeany of the 64-/256-step wiper settings in the RDAC registersand store them in the EEMEM. Once the settings are stored,they are restored automatically to the RDAC registers at systempower-on; the settings can also be restored dynamically.The AD5251/AD5252 provide additional increment,decrement, +6 dB step change, and –6 dB step change insynchronous or asynchronous channel update mode. Theincrement and decrement functions allow stepwise linearadjustments, with a ± 6 dB step change equivalent to doublingor halving the RDAC wiper setting. These functions are usefulfor steep-slope, nonlinear adjustments, such as white LEDbrightness and audio volume control.The AD5251/AD5252 have a patented resistance-tolerancestoring function that allows the user to access the EEMEM andobtain the absolute end-to-end resistance values of the RDACsfor precision applications.The AD5251/AD5252 are available in TSSOP-14 packages.AD5251 has only 50 kΩ resistance options and AD5252 isavailable in 1 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ options. All partsare guaranteed to operate over the –40°C to +105°C extendedindustrial temperature range.APPLICATIONS Mechanical potentiometer replacement General-purpose DAC replacement LCD panel VCOM adjustment White LED brightness adjustment RF base station power amp bias control Programmable gain and offset control Programmable voltage-to-current conversion Programmable power supply Sensor calibrations1 Protected by U.S. Patent 7,688,240.