2 256-Position I C -Compatible Digital Potentiometer AD5245 FEATURES FUNCTIONAL BLOCK DIAGRAM V 256-position DD End-to-end resistance 5 k , 10 k, 50 k, 10 0 k A Compact SOT-23-8 (2.9 mm 3 mm) package SCL 2 I C INTERFACE Fast settling time: tS = 5 s typ on power-up SDA Full read/write of wiper register W AD0 Power-on preset to midscale Extra package address decode pin AD0 WIPER B REGISTER Computer software replaces C in factory programming applications POR Single supply: 2.7 V to 5.5 V GND Low temperature coefficient 45 ppm/C Figure 1. Low power: I = 8 A DD Wide operating temperature: 40C to +125C Evaluation board available PIN CONFIGURATION APPLICATIONS 1 8 A W V 2 AD5245 7 B DD Mechanical potentiometer replacement in new designs TOP VIEW GND 3 6 AD0 LCD panel V adjustment COM (Not to Scale) 4 5 SCL SDA LCD panel brightness and contrast control Figure 2. Transducer adjustment of pressure, temperature, position, chemical, and optical sensors RF amplifier biasing Automotive electronics adjustment Gain control and offset adjustment GENERAL DESCRIPTION The AD5245 provides a compact 2.9 mm 3 mm packaged Operating from a 2.7 V to 5.5 V power supply and consuming solution for 256-position adjustment applications. These less than 8 A allows usage in portable battery-operated devices perform the same electronic adjustment function as applications. mechanical potentiometers or variable resistors, with enhanced Note that the terms digital potentiometer, VR, and RDAC are resolution, solid-state reliability, and superior low temperature used interchangeably. coefficient performance. 2 The wiper settings are controllable through an I C-compatible digital interface, which can also be used to read back the wiper register content. AD0 can be used to place up to two devices on the same bus. Command bits are available to reset the wiper position to midscale or to shut down the device into a state of zero power consumption. Rev. B 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 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 03436-002 03436-001AD5245 TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits..................................................................................... 12 Applications....................................................................................... 1 Theory of Operation ...................................................................... 13 Functional Block Diagram .............................................................. 1 Programming the Variable Resistor......................................... 13 Pin Configuration............................................................................. 1 Programming the Potentiometer Divider............................... 14 General Description ......................................................................... 1 ESD Protection ........................................................................... 14 Revision History ............................................................................... 2 Terminal Voltage Operating Range ......................................... 14 Electrical Characteristics ................................................................. 3 Power-Up Sequence ................................................................... 14 5 k Version .................................................................................. 3 Layout and Power Supply Bypassing ....................................... 14 10 k, 50 k, 100 k Versions .................................................. 4 Constant Bias to Retain Resistance Setting............................. 15 Timing Characteristics..................................................................... 5 Evaluation Board ........................................................................ 15 2 5 k, 10 k, 50 k, 100 k Versions ........................................ 5 I C Interface .................................................................................... 16 2 Absolute Maximum Ratings............................................................ 6 I C-Compatible 2-Wire Serial Bus........................................... 16 ESD Caution.................................................................................. 6 Outline Dimensions ....................................................................... 19 Pin Configuration and Function Descriptions............................. 7 Ordering Guide .......................................................................... 19 Typical Performance Characteristics ............................................. 8 REVISION HISTORY Added Figure 37 ............................................................................ 14 1/06Rev. A to Rev. B Changes to Equation 4.................................................................. 14 Changes to Table 3........................................................................... 5 Deleted Readback RDAC Value Section .................................... 14 Changes to Ordering Guide .........................................................19 Deleted Level Shifting for Bidirectional Interface Section ...... 14 3/04Rev. 0 to Rev. A Moved ESD Protection Section to Page ..................................... 14 Updated Format................................................................ Universal Changes to Figure 38 and Figure 39............................................ 14 Changes to Features......................................................................... 1 Moved Terminal Voltage Operating Range Section to Page.... 14 Changes to Applications ................................................................. 1 Changes to Figure 40..................................................................... 14 Changes to Figure 1......................................................................... 1 Moved Power-Up Sequence Section to Page ............................. 14 Changes to Electrical Characteristics5 k Version ................ 3 Moved Layout and Power Supply Bypassing Section to Page . 15 Changes to Electrical Characteristics10 k, 50 k, Added Constant Bias to Retain Resistance Setting Section..... 15 and 100 k Versions ....................................................................... 4 Added Figure 42 ............................................................................ 15 Changes to Timing Characteristics............................................... 5 Added Evaluation Board Section ................................................ 15 Changes to Absolute Maximum Ratings ...................................... 6 Added Figure 43 ............................................................................ 15 2 Moved ESD Caution to Page.......................................................... 6 Moved I C Interface Section to Page........................................... 16 Changes to Pin Configuration and Function Descriptions ....... 7 Changes to I2C Compatible 2-Wire Serial Bus Section ........... 16 Changes to Figures 22 and 23 ......................................................11 Moved Table 5 and Table 6 to Page ............................................. 17 Moved Figure 25 to Figure 26 ......................................................11 (Renumbered as Table 8 and Table 9) Moved Figure 26 to Figure 27 ......................................................11 Moved Figure 36, Figure 37, and Figure 38 to Page.................. 17 Moved Figure 27 to Figure 25 ......................................................11 (Renumbered as Figure 44, Figure 45, and Figure 46) Deleted Figures 31 and 32 ............................................................12 Moved Multiply Devices on One Bus Section to Page ............. 18 Changes to Figure 32, Figure 33 and Figure 34 .........................12 Updated Ordering Guide ............................................................. 19 Changes to Rheostat Operation Section.....................................13 Updated Outline Dimensions...................................................... 19 2 Added Figure 35.............................................................................13 Moved I C Disclaimer to Page..................................................... 20 Changes to Equation 1 and Equation 2 ......................................13 5/03Revision 0: Initial Version Changes to Table 6 and Table 7....................................................13 Rev. B Page 2 of 20