Features: AD5251: Dual 64-position resolution
AD5252: Dual 256-position resolution
1 k, 10 k, 50 k, 100 k
Nonvolatile memory1 stores wiper setting w/write protection
Power-on refreshed with EEMEM settings in 300 s typ
EEMEM rewrite time = 540 s 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 RDAC2 and EEMEM registers
Predefined linear increment/decrement commands
Predefined ±6 dB step change commands
Synchronous or asynchronous dual-channel update
Wiper setting readback
4 MHz bandwidth-1 k version
Single supply 2.7 V to 5.5 V
Dual supply ±2.25 V to ±2.75 V
2 slave address decoding bits allow operation of 4 devices
100-year typical data retention, TA = 55°C
Operating temperature: 40°C to +85°CApplicationMechanical 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 calibrationsPinout
SpecificationsVDD to GND......................................−0.3 V, +7 V
VSS to GND.......................................+0.3 V, −7 V
VDD to VSS......................................................7 V
VA, VB, VW to GND...................................VSS, VDD
Maximum Current
IWB, IWA Pulsed.....................................±20 mA
IWB Continuous (RWB 1 k, A Open)1..±5 mA
IWA Continuous (RWA 1 k, B Open)1..±5 mA
IAB Continuous (RAB = 1 k/10 k/50 k/100 k)1.±5 mA/±500 A/
±100 A/±50 A
Digital Inputs and Output Voltage to GND.......0 V, 7 V
Operating Temperature Range........−40°C to +85°C
Maximum Junction Temperature (TJMAX)..........150°C
Storage Temperature Range.........−65°C to +150°C
Lead Temperature (Soldering, 10 sec).............300°C
Vapor Phase (60 sec).......................................215°C
Infrared (15 sec)...............................................220°C
TSSOP-14 Thermal Resistance2 JA..............136°C/W
1 Maximum terminal current is bound by the maximum applied voltage across any two of the A, B, and W terminals at a given resistance, the maximum current handling of the switches, and the maximum power dissipation of the package. VDD = 5 V.
2 Package power dissipation = (TJMAX − TA)/JA.
Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DescriptionThe AD5251/AD5252 are dual-channel, I2C, nonvolatile mem-ory, digitally controlled potentiometers with 64/256 positions, respectively. These devices perform the same electronic adjust-ment 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 in 1 k, 10 k, 50 k, and 100 k options. All parts are guaranteed to operate over the 40°C to +85°C extended industrial temperature range.
AD5251 Data Sheet
