AD5253: Quad 64-Position I2C

AD5253:  Quad 64-Position I²C 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 AD5253/AD5254’s versatile programmability allows multiple modes of operation, including read/write accesses 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 modes. The increment and decrement functions allow stepwise linear adjustments, while ±6 dB step changes are equivalent to doubling or halving the RDAC wiper setting. These functions are useful for steep-slope nonlinear adjustment applications 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 +85°C extended industrial temperature range.

1. The terms nonvolatile memory and EEMEM are used interchangeably.
2. The terms digital potentiometer and RDAC are used interchangeably.

Features

• AD5253: Quad 64-position resolution
  AD5254: Quad 256-position resolution
• 1 kΩ, 10 kΩ, 50 kΩ, 100 kΩ
• Nonvolatile memory¹ 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 accesses of RDAC and EEMEM registers
• Predefined linear increment/decrement commands
• Predefined ±6 dB step change commands
• Synchronous or asynchronous quad channel update

Functional Block Diagram for AD5253