32-Position Manual Up/Down Control Potentiometer Data Sheet AD5228 FEATURES FUNCTIONAL BLOCK DIAGRAM 32-position digital potentiometer D UP/DOWN AD5228 10 k , 50 k , 100 k end-to-end terminal resistance E CONTROL V DD C Simple manual up/down control LOGIC O D A Self-contained, requires only 2 pushbutton tactile switches R1 R2 E Built-in adaptive debouncer DISCRETE W STEP/AUTO Discrete step-up/step-down control SCAN DETECT B Autoscan up/down control with 4 steps per second PUSH-UP BUTTON Pin-selectable zero-scale/midscale preset PU Low potentiometer mode tempco, 5 ppm/C ADAPTIVE ZERO- OR MID- PD DEBOUNCER SCALE PRESET Low rheostat mode tempco, 35 ppm/C PUSH-DOWN Digital control compatible BUTTON PRE GND Ultralow power, I = 0.4 A typ and 3 A max DD Low operating voltage, 2.7 V to 5.5 V Temperature range, 40C to +105C Figure 1. Compact thin SOT-23-8 (2.9 mm 3 mm) Pb-free package The AD5228 can increment or decrement the resistance in discrete steps or in autoscan mode. When the PU or PD button APPLICATIONS is pressed briefly (no longer than 0.6 s), the resistance of the Mechanical potentiometer and trimmer replacements AD5228 changes by one step. When the or button is PU PD LCD backlight, contrast, and brightness controls held continuously for more than a second, the device activates Digital volume control Portable device-level adjustments the autoscan mode and changes four resistance steps per Electronic front panel-level controls second. Programmable power supply The AD5228 can also be controlled digitally its up/down features simplify microcontroller usage. The AD5228 is available GENERAL DESCRIPTION in a compact thin SOT-23-8 (TSOT-8) package. The part is The AD5228 is Analog Devices latest 32-step-up/step-down guaranteed to operate over the temperature range of 40C to control digital potentiometer emulating mechanical potenti- +105C. 1 ometer operation . Its simple up/down control interface allows The AD5228s simple interface, small footprint, and very low manual control with just two external pushbutton tactile cost enable it to replace mechanical potentiometers and switches. The AD5228 is designed with a built-in adaptive trimmers with typically 3 improved resolution, solid-state debouncer that ignores invalid bounces due to contact bounce reliability, and faster adjustment, resulting in considerable cost commonly found in mechanical switches. The debouncer is saving in end users systems. adaptive, accommodating a variety of pushbutton tactile Users who consider EEMEM potentiometers should refer to the switches that generally have less than 10 ms of bounce time recommendations in the Applications section. during contact closures. When choosing the switch, the user should consult the timing specification of the switch to ensure Table 1. Truth Table its suitability in an AD5228 application. 1 PU PD Operation 0 0 RWB Decrement 0 1 RWB Increment 1 0 RWB Decrement 1 1 R Does Not Change WB 1 RWA increments if RWB decrements and vice versa. 1 The terms digital potentiometer and RDAC are used interchangeably. Rev. B 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 20042015 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com 04422-0-001AD5228 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Terminal Voltage Operation Range ......................................... 13 Applications ....................................................................................... 1 Power-Up and Power-Down Sequences .................................. 14 General Description ......................................................................... 1 Layout and Power Supply Biasing ............................................ 14 Revision History ............................................................................... 2 Applicat ions ..................................................................................... 15 Electrical Characteristics ................................................................. 3 Manual Adjustable LED Driver ................................................ 15 Interface Timing Diagrams ......................................................... 4 Adjustable Current Source for LED Driver ............................ 15 Absolute Maximum Ratings ............................................................ 5 Adjustable High Power LED Driver ........................................ 15 ESD Caution .................................................................................. 5 Automatic LCD Panel Backlight Control ................................ 16 Pin Configuration and Function Descriptions ............................. 6 Audio Amplifier with Volume Control ................................... 16 Typical Performance Characteristics ............................................. 7 Constant Bias with Supply to Retain Resistance Setting ...... 17 Theory of Operation ...................................................................... 11 Outline Dimensions ....................................................................... 18 Programming the Digital Potentiometers ............................... 12 Ordering Guide .......................................................................... 18 Controlling Inputs ...................................................................... 13 REVISION HISTORY 6/15Rev. A to Rev. B Changes to Features Section and General Description Section .... 1 Changes to Ordering Guide ........................................................... 18 4/09Rev. 0 to Rev. A Changes to Table 23 4/04Revision 0: Initial Version Rev. B Page 2 of 18