Nonvolatile Memory, 1024-Position Digital Potentiometer Data Sheet AD5231 FEATURES FUNCTIONAL BLOCK DIAGRAM 1024-position resolution AD5231 CS V DD Nonvolatile memory maintains wiper setting ADDR RDAC RDAC CLK DECODE REGISTER Power-on refresh with EEMEM setting A SDI SDI EEMEM restore time: 140 s typ W SERIAL Full monotonic operation GND EEMEM(0) INTERFACE B 10 k, 50 k, and 100 k terminal resistance Permanent memory write protection SDO SDO DIGITAL O1 REGISTER Wiper setting readback WP 2 DIGITAL EEMEM O2 OUTOUT Predefined linear increment/decrement instructions CONTROL BUFFER RDY Predefined 6 dB/step log taper increment/decrement EEMEM(1) V instructions 28 BYTES SS USER EEMEM SPI-compatible serial interface PR 3 V to 5 V single-supply or 2.5 V dual-supply operation Figure 1. 28 bytes extra nonvolatile memory for user-defined data 100 100-year typical data retention, T = 55C A R R WA WB APPLICATIONS 75 Mechanical potentiometer replacement Instrumentation: gain, offset adjustment Programmable voltage to current conversion 50 Programmable filters, delays, time constants Programmable power supply Low resolution DAC replacement 25 Sensor calibration 0 0 256 512 768 1023 CODE (Decimal) Figure 2. RWA (D) and RWB (D) vs. Decimal Code GENERAL DESCRIPTION 1 resistance between Terminals WA and Terminals WB. This The AD5231 is a nonvolatile memory , digitally controlled 2 setting can be stored into the EEMEM and is transferred potentiometer with 1024-step resolution. The device performs automatically to the RDAC register during system power-on. the same electronic adjustment function as a mechanical potentiometer with enhanced resolution, solid state reliability, The EEMEM content can be restored dynamically or through and remote controllability. The AD5231 has versatile programming PR WP external strobing, and a function protects EEMEM that uses a standard 3-wire serial interface for 16 modes of contents. To simplify the programming, the linear-step increment operation and adjustment, including scratchpad programming, or decrement commands can be used to move the RDAC wiper memory storing and restoring, increment/decrement, 6 dB/step up or down, one step at a time. The 6 dB step commands can log taper adjustment, wiper setting readback, and extra EEMEM be used to double or half the RDAC wiper setting. for user-defined information, such as memory data for other The AD5231 is available in a 16-lead TSSOP. The part is components, look-up table, or system identification information. guaranteed to operate over the extended industrial temperature In scratchpad programming mode, a specific setting can be range of 40C to +85C. programmed directly to the RDAC register that sets the 1 The terms nonvolatile memory and EEMEM are used interchangeably. 2 The terms digital potentiometer and RDAC are used interchangeably. Rev. D 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. 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Technical Support www.analog.com R (D), R (D) (% of Nominal R ) WA WB AB 02739-002 02739-001AD5231 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Latched Digital Outputs ............................................................ 16 Applications ....................................................................................... 1 Advanced Control Modes ......................................................... 18 Functional Block Diagram .............................................................. 1 RDAC Structure.......................................................................... 19 General Description ......................................................................... 1 Programming the Variable Resistor ......................................... 19 Revision History ............................................................................... 2 Programming the Potentiometer Divider ............................... 20 Specifications ..................................................................................... 3 Programming Examples ............................................................ 21 Electrical Characteristics10 k, 50 k, 100 k Versions .. 3 Flash/EEMEM Reliability .......................................................... 22 Timing Characteristics10 k, 50 k, 100 k Versions ...... 5 Applications ..................................................................................... 23 Absolute Maximum Ratings ............................................................ 7 Bipolar Operation from Dual Supplies.................................... 23 ESD Caution .................................................................................. 7 High Voltage Operation ............................................................ 23 Pin Configuration and Function Descriptions ............................. 8 Bipolar Programmable Gain Amplifier ................................... 23 Typical Performance Characteristics ............................................. 9 10-Bit Bipolar DAC .................................................................... 23 Test Circuits ..................................................................................... 13 10-Bit Unipolar DAC ................................................................. 24 Theory of Operation ...................................................................... 14 Programmable Voltage Source with Boosted Output ........... 24 Scratchpad and EEMEM Programming .................................. 14 Programmable Current Source ................................................ 24 Basic Operation .......................................................................... 14 Programmable Bidirectional Current Source ......................... 25 EEMEM Protection .................................................................... 14 Resistance Scaling ...................................................................... 25 Digital Input/Output Configuration ........................................ 15 RDAC Circuit Simulation Model ............................................. 26 Serial Data Interface ................................................................... 15 Outline Dimensions ....................................................................... 27 Daisy-Chain Operation ............................................................. 15 Ordering Guide .......................................................................... 27 Terminal Voltage Operation Range ......................................... 16 Power-Up Sequence ................................................................... 16 REVISION HISTORY 5/04Rev. 0 to Rev. A 3/13Rev. C to Rev. D Updated formatting ............................................................ Universal Added t Table 2 ............................................................................ 5 WP Edits to Features, General Description, and Block Diagram ....... 1 Changes to Ordering Guide .......................................................... 27 Changes to Specifications ................................................................. 3 1/07Rev. B to Rev. C Replaced Timing Diagrams.............................................................. 6 Updated Format .................................................................. Universal Changes to Pin Function Descriptions ........................................... 8 Changes to Dynamic Characteristics Specifications ..................... 4 Changes to Typical Performance Characteristics.......................... 9 Changes to Table 2 Footnote ............................................................ 5 Changes to Test Circuits ................................................................. 13 Changes to Table 3 ............................................................................. 7 Edits to Theory of Operation ......................................................... 14 Edits to Applications ....................................................................... 23 Changes to Ordering Guide ........................................................... 27 Updated Outline Dimensions ........................................................ 27 9/04Rev. A to Rev. B 12/01Revision 0: Initial Version Updated Format .................................................................. Universal Changes to Table 20 ......................................................................... 23 Changes to Resistance Scaling Section ......................................... 25 Changes to Ordering Guide ........................................................... 27 Rev. D Page 2 of 28