Datasheet AD5232 (Analog Devices)

Nonvolatile Memory, Dual 256-Position Digital Potentiometer Data Sheet AD5232 FEATURES FUNCTIONAL BLOCK DIAGRAM Dual-channel, 256-position resolution VDD 10 kΩ, 50 kΩ, and 100 kΩ nominal terminal resistance AD5232 ADDR CS Nonvolatile memory maintenance of wiper settings RDAC1 DECODE REGISTER CLK Predefined linear increment/decrement instructions A1 SERIAL Predefined ±6 dB step log taper increment/decrement SDI W1 INTERFACE B1 instructions SDO EEMEM1 RDAC1 SPI-compatible serial interface Wiper settings and EEMEM readback POWER-ON RDAC2 3 V to 5 V single-supply operation PR RESET REGISTER A2 ±2.5 V dual-supply operation W2 14 bytes of general-purpose user EEMEM WP EEMEM B2 EEMEM2 Permanent memory write protection RDAC2 CONTROL RDY 100-year typical data retention (TA = 55°C) 14 BYTES USER APPLICATIONS EEMEM Mechanical potentiometer replacement
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Instrumentation: gain and offset adjustment GND V
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Programmable voltage-to-current conversion
Figure 1.
Programmable filters, delays, and time constants Programmable power supply Low resolution DAC replacement Sensor calibration GENERAL DESCRIPTION
The AD5232 device provides a nonvolatile, dual-channel, All internal register contents can be read via the serial data digitally controlled variable resistor (VR) with 256-position output (SDO). This includes the RDAC1 and RDAC2 registers, resolution. This device performs the same electronic adjustment the corresponding nonvolatile EEMEM1 and EEMEM2 registers, function as a mechanical potentiometer with enhanced resolution, and the 14 spare USER EEMEM registers that are available for solid state reliability, and superior low temperature coefficient constant storage. performance. The versatile programming of the AD5232, per- The basic mode of adjustment is the increment and decrement ormed via a microcontroller, allows multiple modes of operation command instructions that control the wiper position setting and adjustment. register (RDACx). An internal scratch pad RDACx register can In the direct program mode, a predetermined setting of the RDAC be moved up or down one step of the nominal resistance between registers (RDAC1 and RDAC2) can be loaded directly from the Terminal A and Terminal B. This step adjustment linearly changes microcontroller. Another important mode of operation allows the wiper to Terminal B resistance (RWB) by one position segment the RDACx register to be refreshed with the setting previously of the device’s end-to-end resistance (RAB). For exponential/ stored in the corresponding EEMEM register (EEMEM1 and logarithmic changes in wiper setting, a left/right shift command EEMEM2). When changes are made to the RDACx register to instruction adjusts the levels in ±6 dB steps, which can be useful establish a new wiper position, the value of the setting can be for audio and light alarm applications. saved into the EEMEMx register by executing an EEMEM save The AD5232 is available in a thin, 16-lead TSSOP package. operation. After the settings are saved in the EEMEMx register, All parts are guaranteed to operate over the extended industrial these values are automatically transferred to the RDACx register temperature range of −40°C to +85°C. An evaluation board, the to set the wiper position at system power-on. Such operation is EVAL-AD5232-10EBZ, is available. enabled by the internal preset strobe. The preset strobe can also be accessed externally.
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Document Outline Features Applications Functional Block Diagram General Description Revision History Specifications Electrical Characteristics—10 kΩ, 50 kΩ, 100 kΩ Versions Interface Timing Characteristics Timing Diagrams Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Test Circuits Theory of Operation Scratch Pad and EEMEM Programming Basic Operation EEMEM Protection Digital Input/Output Configuration Serial Data Interface Daisy-Chaining Operation Advanced Control Modes Increment and Decrement Commands Logarithmic Taper Mode Adjustment Using Additional Internal, Nonvolatile EEMEM Terminal Voltage Operating Range Detailed Potentiometer Operation Programming the Variable Resistor Rheostat Operation Programming the Potentiometer Divider Voltage Output Operation Operation from Dual Supplies Application Programming Examples Equipment Customer Start-up Sequence for a PCB Calibrated Unit with Protected Settings Flash/EEMEM Reliability Evaluation Board Outline Dimensions Ordering Guide