Quad 256-Position IC Nonvolatile Memory, Digital Potentiometer

The AD5253 / AD5254 are quad-channel, I2C, nonvolatile memory, digitally controlled potentiometers with 64/256 positions, respectively. These devices perform the same electronic adjustment functions as mechanical potentiometers, trimmers, and variable resistors.

The parts’ versatile programmability allows multiple modes of operation, including read/write access in the RDAC 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 as memory data for other components, look-up table, or system identification information.

The AD5253 / AD5254 allow the host I2C controllers to write any of the 64-/256-step wiper settings in the RDAC registers and store them in the EEMEM. Once the settings are stored, they are restored automatically to the RDAC registers at system power-on; the settings can also be restored dynamically.

The AD5253 / AD5254 provide additional increment, decrement, +6 dB step change, and –6 dB step change in synchronous or asynchronous channel update mode. The increment and decrement functions allow stepwise linear adjustments, with a ± 6 dB step change equivalent to doubling or halving the RDAC wiper setting. These functions are useful for steep-slope, nonlinear adjustments, such as white LED brightness and audio volume control.

The AD5253 / AD5254 have a patented resistance-tolerance storing function that allows the user to access the EEMEM and obtain the absolute end-to-end resistance values of the RDACs for precision applications.

The AD5253 / AD5254 are available in TSSOP-20 packages in 1 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ options. All parts are guaranteed to operate over the –40°C to +105°C extended industrial temperature range. In this data sheet, the nonvolatile memory and EEMEM terms are used interchangeably, as are the digital potentiometer and RDAC terms.

APPLICATIONS

* Mechanical potentiometer replacement

* Low resolution DAC replacement

* RGB LED backlight control

* White LED brightness adjustment

* RF base station power amp bias control

* Programmable gain and offset control

* Programmable attenuators

* Programmable voltage-to-current conversion

* Programmable power supply

* Programmable filters

* Sensor calibrations

* Quad 256-position resolution

* 1 kΩ, 10 kΩ, 50 kΩ, 100 kΩ

* Nonvolatile memory stores wiper settings w/write protection

* Power-on refreshed to EEMEM settings in 300 μs typ

* EEMEM rewrite time = 540 μs typ

* Resistance tolerance stored in nonvolatile memory

* 12 extra bytes in EEMEM for user-defined information

* I2C-compatible serial interface

* Direct read/write access of RDAC and EEMEM registers