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256-Position, Ultralow Power 1.8 V Logic-Level Digital Potentiometer AD5165
FEATURES
Ultralow standby power IDD = 50 nA typical 256-position End-to-end resistance 100 kΩ Logic high voltage 1.8 V Power supply 2.7 V to 5.5 V Low temperature coefficient 35 ppm/°C Compact thin 8-lead TSOT-8 (2.9 mm × 2.8 mm) package Simple 3-wire digital interface Wide operating temperature −40°C to +125°C Pin-to-pin compatible to AD5160 with CS inverted
FUNCTIONAL BLOCK DIAGRAM
VDD A CS SDI CLK 3-WIRE INTERFACE W
WIPER REGISTER
B
04749-0-001
GND
APPLICATIONS
Battery-operated electronics adjustment Remote utilities meter adjustment Mechanical potentiometer replacement Transducer circuit adjustment Automotive electronics adjustment Gain control and offset adjustment System calibration VCXO adjustment
Figure 1.
PIN CONFIGURATION
W 1 VDD 2
8
A
04749-0-002
B TOP VIEW GND 3 (Not to Scale) 6 CS 5 SDI CLK 4
7
AD5165
GENERAL OVERVIEW
The AD5165 provides a compact 2.9 mm × 2.8 mm packaged solution for 256-position adjustment applications. These devices perform the same electronic adjustment function as mechanical potentiometers or variable resistors, with enhanced resolution, solid-state reliability, and superior low temperature coefficient performance. The AD5165’s supply voltage requirement is 2.7 V to 5.5 V, but its logic voltage requirement is 1.8 V to VDD. The AD5165 consumes very low quiescent power during standby mode and is ideal for battery-operated applications. Wiper settings are controlled through a simple 3-wire interface. The interface is similar to the SPI® digital interface except for the inverted chip-select function that minimizes logic power consumption in the idling state. The resistance between the wiper and either endpoint of the fixed resistor varies linearly with respect to the digital code transferred into the wiper register. Operating from a 2.7 V to 5.5 V power supply and consuming less than 50 nA typical standby power allows use in batteryoperated portable or remote utility device applications.
Figure 2.
TYPICAL APPLICATION
5V VOH = 1.8V MIN VDD 3.3V
AD5165
CS CLK SDI GND
VA VW WIDE TERMINAL VOLTAGE RANGE: 0V < VA,VB,VW < 5V
04749-0-003
DIGITAL CONTROL LOGIC OR MICRO
VB
Figure 3.
Note: The terms digital potentiometer, RDAC, and VR are used interchangeably.
Rev. 0
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AD5165 TABLE OF CONTENTS
Electrical Characteristics—100 kΩ Version .................................. 3 Absolute Maximum Ratings............................................................ 5 Pin Configuration and Functional Descriptions.......................... 6 Typical Performance Characteristics ............................................. 7 Test Circuits..................................................................................... 11 3-Wire Digital Interface................................................................. 12 Theory of Operation ...................................................................... 13 Programming the Variable Resistor ......................................... 13 Programming the Potentiometer Divider ............................... 14 3-Wire Serial Bus Digital Interface .......................................... 14 ESD Protection ........................................................................... 14 Terminal Voltage Operating Range.......................................... 14 Power-Up Sequence ................................................................... 14 Layout and Power Supply Bypassing ....................................... 15 Evaluation Board ........................................................................ 15 Outline Dimensions ....................................................................... 16 Ordering Guide .......................................................................... 16
REVISION HISTORY 4/04—Revision 0: Initial Version
Rev. 0 | Page 2 of 16
AD5165 ELECTRICAL CHARACTERISTICS—100 kΩ VERSION
VDD = 5 V ± 10%, or 3 V ± 10%; VA = VDD; VB = 0 V; –40°C < TA < +125°C; unless otherwise noted. Table 1.
Parameter Symbol DC CHARACTERISTICS—RHEOSTAT MODE Resistor Differential Nonlinearity2 R-DNL Resistor Integral Nonlinearity2 R-INL Nominal Resistor Tolerance3 ∆RAB/RAB Resistance Temperature Coefficient (∆RAB/RAB)/∆Tx106 Wiper Resistance RW DC CHARACTERISTICS—POTENTIOMETER DIVIDER MODE Resolution N Differen.