Dual, 256-Tap, Nonvolatile, I²C-Interface, Digital Potentiometers

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.Applications

* Liquid-Crystal Display (LCD) Contrast Control * Low-Drift Programmable-Gain Amplifiers * Mechanical Potentiometer Replacements * Volume Control

* Power-On Recall of Wiper Position from Nonvolatile Memory

* EEPROM Write Protection

* Tiny 3mm x 3mm x 0.8mm Thin QFN Package

* 70ppm/°C End-to-End Resistance Temperature Coefficient

* 10ppm/°C Ratiometric Temperature Coefficient

* Fast 400kbps I²C-Compatible Serial Interface

* 1µA (max) Static Supply Current

* Single-Supply Operation: +2.7V to +5.25V

* 256 Tap Positions per Potentiometer

* ±0.5 LSB DNL in Voltage-Divider Mode

* ±1 LSB INL in Voltage-Divider Mode