The AD5252 is a dual channel, digitally controlled variable resistor (VR) with resolutions of 256 positions. This device performs the same electronic adjustment function as a potentiometer or variable resistor. The AD5252’s versatile programming via a Micro Controller allows multiple modes of operation and adjustment.
In the direct program mode a predetermined setting of the RDAC register can be loaded directly from the micro controller. Another key mode of operation allows the RDAC register to be refreshed with the setting previously stored in the EEMEM register. When changes are made to the RDAC register to establish a new wiper position, the value of the setting can be saved into the EEMEM by executing an EEMEM save operation. Once the settings are saved in the EEMEM register, these values will be transferred automatically to the RDAC register to set the wiper position at system power ON. Such operation is enabled by the internal preset strobe and the preset can also be accessed externally.
The basic mode of adjustment is the increment and decrement from the present setting of the Wiper position setting (RDAC) register. An internal scratch pad RDAC register can be moved UP or DOWN, one step of the nominal resistance between terminals A-and-B. This linearly changes the wiper-to-B terminal resistance (RWB) by one out of 64/256 positions of the AD5251/AD5252 end- to-end resistance (RAB). For non-linear changes in wiper setting, a left/right shift command adjusts levels in 6dB steps, which can be useful for sound and light alarm applications.
The AD5251/AD5252 is available in the thin TSSOP-14 package. All parts are guaranteed to operate over the extended industrial temperature range of -40°C to +125°C.
### Features and Benefits
Nonvolatile Memory Maintains Wiper Settings
Resistance Tolerance Stored In Nonvolatile Memory
1 k Ω, 10 k Ω, 50 k Ω 100 k Ω
I2C Compatible Serial Interface
Wiper Settings Read Back
Linear Increment/Decrement Predefined Instructions
±6 dB Log taper Increment/Decrement Predefined Instructions
Single Supply 2.7 V to 5.5 V
Logic Operation Voltage 3 V to 5 V
Power On Presets to EEMEM Settings with Refresh Time < 1 ms
