Nonvolatile Memory, Dual 256-Position Digital Potentiometer Data Sheet AD5232 FEATURES FUNCTIONAL BLOCK DIAGRAM V DD Dual-channel, 256-position resolution 10 k, 50 k, and 100 k nominal terminal resistance AD5232 ADDR CS RDAC1 Nonvolatile memory maintenance of wiper settings DECODE REGISTER CLK A1 Predefined linear increment/decrement instructions SERIAL SDI W1 Predefined 6 dB step log taper increment/decrement INTERFACE B1 SDO EEMEM1 instructions RDAC1 SPI-compatible serial interface Wiper settings and EEMEM readback POWER-ON RDAC2 PR REGISTER 3 V to 5 V single-supply operation RESET A2 2.5 V dual-supply operation W2 14 bytes of general-purpose user EEMEM WP B2 EEMEM EEMEM2 RDAC2 CONTROL RDY Permanent memory write protection 100-year typical data retention (T = 55C) A 14 BYTES USER EEMEM APPLICATIONS Mechanical potentiometer replacement Instrumentation: gain and offset adjustment GND V SS 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 devices end-to-end resistance (R ). For exponential/ AB 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 40C to +85C. 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. Rev. C Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20012013 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 02618-001AD5232 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Digital Input/Output Configuration........................................ 14 Applications ....................................................................................... 1 Serial Data Interface ................................................................... 15 Functional Block Diagram .............................................................. 1 Daisy-Chaining Operation........................................................ 15 General Description ......................................................................... 1 Advanced Control Modes ......................................................... 17 Revision History ............................................................................... 2 Using Additional Internal, Nonvolatile EEMEM ................... 18 Specifications ..................................................................................... 3 Terminal Voltage Operating Range ......................................... 18 Electrical Characteristics10 k, 50 k, 100 k Versions .. 3 Detailed Potentiometer Operation .......................................... 18 Interface Timing Characteristics ................................................ 5 Programming the Variable Resistor ......................................... 19 Absolute Maximum Ratings ............................................................ 7 Programming the Potentiometer Divider ............................... 20 Thermal Resistance ...................................................................... 7 Operation from Dual Supplies ................................................. 20 ESD Caution .................................................................................. 7 Application Programming Examples ...................................... 20 Pin Configuration and Function Descriptions ............................. 8 Equipment Customer Start-up Sequence for a PCB Calibrated Unit with Protected Settings ................ 21 Typical Performance Characteristics ............................................. 9 Flash/EEMEM Reliability .......................................................... 21 Test Circuits ..................................................................................... 12 Evaluation Board ........................................................................ 21 Theory of Operation ...................................................................... 14 Outline Dimensions ....................................................................... 22 Scratch Pad and EEMEM Programming................................. 14 Ordering Guide .......................................................................... 22 Basic Operation .......................................................................... 14 EEMEM Protection .................................................................... 14 REVISION HISTORY Changes to Applications Section ..................................................... 1 11/13Rev. B to Rev. C Change to Wiper Resistance Parameter, Table 1 ........................... 3 Changed t16 from 25 ms (max) to 25 ms (typ) Table 2 ............... 5 CS Changes to Rise to RDY Fall Time Parameter, Table 2........... 5 Changes to Ordering Guide .......................................................... 22 Changes to Figure 2 and Figure 3 .................................................... 6 09/11Rev. A to Rev. B Changes to Figure 24 ...................................................................... 12 Change to Resistor Noise Voltage Parameter in Table 1 ............. 4 Added Figure 32 ............................................................................. 13 Changes to Serial Data Interface Section .................................... 15 10/09Rev. 0 to Rev. A Changes to Programming the Variable Resistor Section .......... 19 Updated Format .................................................................. Universal Changes to Ordering Guide .......................................................... 22 Changes to Data Sheet Title ............................................................ 1 Changes to Features Section............................................................ 1 10/01Revision 0: Initial Version Rev. C Page 2 of 24