Datasheet AD5227 (Analog Devices)

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64-Position Up/Down Control Digital Potentiometer AD5227 FEATURES FUNCTIONAL BLOCK DIAGRAM 64-position digital potentiometer VDD 10 kΩ, 50 kΩ, 100 kΩ end-to-end terminal resistance AD5227 Simple up/down digital or manual configurable control Midscale preset CS A 6-BIT UP/DOWN Low potentiometer mode tempco = 10 ppm/°C U/D CONTROL W LOGIC Low rheostat mode tempco = 35 ppm/°C CLK B Ultralow power, IDD = 0.4 μA typ and 3 μA max Fast adjustment time, ts = 1 μs GND Chip select enable multiple device operation POR WIPER MIDSCALE REGISTER Low operating voltage, 2.7 V to 5.5 V
04419-0-001
Automotive temperature range, −40°C to +105°C
Figure 1.
Compact thin SOT-23-8 (2.9 mm × 3 mm) Pb-free package APPLICATIONS Mechanical potentiometer and trimmer replacements LCD backlight, contrast, and brightness controls Portable electronics level adjustment Programmable power supply Digital trimmer replacements Automatic closed-loop control GENERAL DESCRIPTION
The AD5227 is Analog Devices’ latest 64-step up/down control The AD5227 is available in a compact thin SOT-23-8 (TSOT-8) digital potentiometer1. This device performs the same electronic Pb-free package. The part is guaranteed to operate over the adjustment function as a 5 V potentiometer or variable resistor. automotive temperature range of −40°C to +105°C. Its simple 3-wire up/down interface allows manual switching or high speed digital control. The AD5227 presets to midscale at Users who consider EEMEM potentiometers should refer to power-up. When CS is enabled, the devices changes step at some recommendations in the Applications section. every clock pulse. The direction is determined by the state of
Table 1. Truth Table
the U/D pin (see Table 1). The interface is simple to activate by
CS Operation1 CLK U/D
any host controller, discrete logic, or manually with a rotary 0 ↓ 0 RWB Decrement encoder or pushbuttons. The AD5227’s 64-step resolution, small 0 ↓ 1 RWB Increment footprint, and simple interface enable it to replace mechanical 1 X X No Operation potentiometers and trimmers with typically 6× improved resolution, solid-state reliability, and design layout flexibility, 1 RWA increments if RWB decrements and vice versa. resulting in a considerable cost savings in end users’ systems. 1 The terms digital potentiometer and RDAC are used interchangeably.
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM 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 DIGITAL INTERFACE TERMINAL VOLTAGE OPERATION RANGE POWER-UP AND POWER-DOWN SEQUENCES LAYOUT AND POWER SUPPLY BIASING APPLICATIONS MANUAL CONTROL WITH TOGGLE AND PUSHBUTTON SWITCHES MANUAL CONTROL WITH ROTARY ENCODER ADJUSTABLE LED DRIVER ADJUSTABLE CURRENT SOURCE FOR LED DRIVER ADJUSTABLE HIGH POWER LED DRIVER AUTOMATIC LCD PANEL BACKLIGHT CONTROL 6-BIT CONTROLLER CONSTANT BIAS WITH SUPPLY TO RETAIN RESISTANCE SETTING OUTLINE DIMENSIONS ORDERING GUIDE