IC, Nonvolatile Memory, Dual 64-Position Digital Potentiometer

The AD52511 is a dual-channel, I2C, nonvolatile memory, digitally controlled potentiometer with 64 positions. 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 AD5251/AD5252 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 AD5251/AD5252 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 AD5251/AD5252 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 AD5251/AD5252 are available in TSSOP-14 packages. AD5251 has only 50 kΩ resistance options and AD5252 is available 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.

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 calibrations

1 Protected by U.S. Patent 7,688,240.

* AD5251: Dual 64-position resolution* AD5252: Dual 256-position resolution* AD5251: 50 kΩ* AD5252: 1 kΩ, 10 kΩ, 50 kΩ, 100 kΩ* Nonvolatile memory stores wiper setting w/write protection* Power-on refreshed with 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