Datasheet AD5228 (Analog Devices)

link to page 15
32-Position Manual Up/Down Control Potentiometer Data Sheet AD5228 FEATURES FUNCTIONAL BLOCK DIAGRAM 32-position digital potentiometer 10 kΩ, 50 kΩ, 100 kΩ end-to-end terminal resistance UP/DOWN D AD5228 E Simple manual up/down control V CONTROL DD LOGIC C O Self-contained, requires only 2 pushbutton tactile switches D A R1 R2 Built-in adaptive debouncer E DISCRETE W Discrete step-up/step-down control STEP/AUTO Autoscan up/down control with 4 steps per second SCAN DETECT B PUSH-UP Pin-selectable zero-scale/midscale preset BUTTON PU Low potentiometer mode tempco, 5 ppm/°C ADAPTIVE ZERO- OR MID- Low rheostat mode tempco, 35 ppm/°C PD DEBOUNCER SCALE PRESET Digital control compatible PUSH-DOWN BUTTON
04422-0-001
Ultralow power, IDD = 0.4 µA typ and 3 µA max PRE GND Low operating voltage, 2.7 V to 5.5 V Temperature range, −40°C to +105°C
Figure 1.
Compact thin SOT-23-8 (2.9 mm × 3 mm) Pb-free package
The AD5228 can increment or decrement the resistance in
APPLICATIONS
discrete steps or in autoscan mode. When the PU or PD button
Mechanical potentiometer and trimmer replacements
is pressed briefly (no longer than 0.6 s), the resistance of the
LCD backlight, contrast, and brightness controls
AD5228 changes by one step. When the PU or PD button is
Digital volume control
held continuously for more than a second, the device activates
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
GENERAL DESCRIPTION
features simplify microcontroller usage. The AD5228 is available 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 −40°C to control digital potentiometer emulating mechanical potenti- +105°C. ometer operation1. Its simple up/down control interface allows The AD5228’s 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 typical y 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 switches that generally have less than 10 ms of bounce time Users who consider EEMEM potentiometers should refer to the during contact closures. When choosing the switch, the user recommendations in the Applications section. should consult the timing specification of the switch to ensure
Table 1. Truth Table
its suitability in an AD5228 application.
PU PD Operation1
0 0 R WB Decrement 0 1 RWB Increment 1 0 RWB Decrement 1 1 RWB Does Not Change 1RWA 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 rights of third parties that may result from its use. Specifications subject to change without notice. No One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 ©2004–2015 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com
Document Outline FEATURES APPLICATIONS GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY ELECTRICAL CHARACTERISTICS INTERFACE TIMING DIAGRAMS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION PROGRAMMING THE DIGITAL POTENTIOMETERS Rheostat Operation Potentiometer Mode Operation CONTROLLING INPUTS TERMINAL VOLTAGE OPERATION RANGE POWER-UP AND POWER-DOWN SEQUENCES LAYOUT AND POWER SUPPLY BIASING APPLICATIONS MANUAL ADJUSTABLE LED DRIVER ADJUSTABLE CURRENT SOURCE FOR LED DRIVER ADJUSTABLE HIGH POWER LED DRIVER AUTOMATIC LCD PANEL BACKLIGHT CONTROL AUDIO AMPLIFIER WITH VOLUME CONTROL CONSTANT BIAS WITH SUPPLY TO RETAIN RESISTANCE SETTING OUTLINE DIMENSIONS ORDERING GUIDE