The MAX5477/MAX5478/MAX5479 nonvolatile, dual, linear-taper, digital potentiometers perform the function of a mechanical potentiometer, but replace the mechanics with a simple 2-wire digital interface. Each device performs the same function as a discrete potentiometer or variable resistor and has 256 tap points.The devices feature an internal, nonvolatile EEPROM used to store the wiper position for initialization during power-up. A write-protect feature prevents accidental overwrites of the EEPROM. The fast-mode I²C-compatible serial interface allows communication at data rates up to 400kbps, minimizing board space and reducing interconnection complexity in many applications. Three address inputs allow a total of eight unique address combinations.The MAX5477/MAX5478/MAX5479 provide three nominal resistance values: 10kΩ (MAX5477), 50kΩ (MAX5478), or 100kΩ (MAX5479). The nominal resistor temperature coefficient is 70ppm/°C end-to-end and 10ppm/°C ratiometric. The low temperature coefficient makes the devices ideal for applications requiring a low temperature- coefficient variable resistor, such as low drift, programmable gain-amplifier circuit configurations.The MAX5477/MAX5478/MAX5479 are available in 16-pin 3mm x 3mm x 0.8mm TQFN and 14-pin 4.4mm x 5mm TSSOP packages. These devices operate over the extended -40°C to +85°C temperature range.ApplicationsLiquid-Crystal Display (LCD) Contrast ControlLow-Drift Programmable-Gain AmplifiersMechanical Potentiometer ReplacementsVolume Control