Single/Dual, +15 V/±5 V, 256-Position, IC-Compatible Digital Potentiometer

The AD5280/AD5282 are single-channel and dual-channel, 256-position, digitally controlled variable resistors (VRs)2. The devices perform the same electronic adjustment function as a potentiometer, trimmer, or variable resistor. Each VR offers a completely programmable value of resistance between the A terminal and the wiper or the B terminal and the wiper. The fixed A-to-B terminal resistance of 20 kΩ, 50 kΩ, or 200 kΩ has a 1% channel-to-channel matching tolerance. The nominal temperature coefficient of both parts is 30 parts per million/ degrees centigrade (ppm/°C). Another key feature is that the parts can operate up to +15 V or ±5 V.

Wiper position programming defaults to midscale at system power-on. When powered, the VR wiper position is programmed by an I2C-compatible, 2-wire serial data interface. The AD5280/ AD5282 feature sleep mode programmability. This allows any level of preset in power-up and is an alternative to a costly EEPROM solution. Both parts have additional programmable logic outputs that enable users to drive digital loads, logic gates, LED drivers, and analog switches in their system.

The AD5280/AD5282 are available in thin, surface-mounted 14-lead TSSOP and 16-lead TSSOP. All parts are guaranteed to operate over the extended industrial temperature range of −40°C to +85°C. For 3-wire SPI-compatible interface applica-tions, see the AD5260/AD5262 product information on www.analog.com.

Applications

* Multimedia, video, and audio

* Communications

* Mechanical potentiometer replacement

* Instrumentation: gain, offset adjustment

* Programmable voltage source

* Programmable current source

* Line impedance matching

1 Assert shutdown and program the device during power-up, then deassert the shutdown to achieve the desired preset level.

2 The terms digital potentiometer, VR, and RDAC are used interchangeably.

* AD5280: 1 channel * AD5282: 2 channels * 256 positions * +10 V to +15 V single supply; ±5.5 V dual-supply operation * Fixed terminal resistance: 20 kΩ, 50 kΩ, 200 kΩ