Datasheet

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Dual, 256-Position, SPI

Digital Potentiometer

AD5162

Rev. C

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FEATURES

2-channel, 256-position potentiometer

End-to-end resistance: 2.5 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ

Compact 10-lead MSOP (3 mm × 4.9 mm) package

Fast settling time: t

= 5 µs typical on power-up

Full read/write of wiper register

Power-on preset to midscale

Computer software replaces microcontroller in factory

programming applications

Single supply: 2.7 V to 5.5 V

Low temperature coefficient: 35 ppm/°C

Low power: I

= 6 µA maximum

Wide operating temperature: −40°C to +125°C

Evaluation board available

Qualified for automotive applications

APPLICATIONS

Systems calibrations

Electronics level settings

Mechanical trimmers replacement in new designs

Permanent factory PCB setting

Transducer adjustment of pressure, temperature, position,

chemical, and optical sensors

RF amplifier biasing

Automotive electronics adjustment

Gain control and offset adjustment

FUNCTIONAL BLOCK DIAGRAM

A = 0 A = 1

GND

SDI

CLK

WIPER

SPI INTERFACE

AD5162

04108-0-001

B1 W2

IPER

Figure 1.

GENERAL DESCRIPTION

The AD5162 provides a compact 3 mm × 4.9 mm packaged

solution for dual, 256-position adjustment applications. This

device performs the same electronic adjustment function as a

3-terminal mechanical potentiometer. Available in four end-to-

end resistance values (2.5 kΩ, 10 kΩ, 50 kΩ, 100 kΩ), this low

temperature coefficient device is ideal for high accuracy and

stability-variable resistance adjustments. The wiper settings are

controllable through an SPI digital interface. The resistance

between the wiper and either endpoint of the fixed resistor

varies linearly with respect to the digital code transferred into

the RDAC latch.

Operating from a 2.7 V to 5.5 V power supply and consuming

less than 6 µA allows the AD5162 to be used in portable battery-

operated applications.

For applications that program the AD5162 at the factory,

Analog Devices offers device programming software running

on Windows® NT/2000/XP operating systems. This software

effectively replaces the need for external SPI controllers, which

in turn enhances the time to market of systems. An AD5162

evaluation kit and software are available. The kit includes a

cable and instruction manual.

The terms digital potentiometer, VR, and RDAC are used interchangeably.

Summary of content (20 pages)

PAGE 1
Dual, 256-Position, SPI Digital Potentiometer AD5162 2-channel, 256-position potentiometer End-to-end resistance: 2.5 kΩ, 10 kΩ, 50 kΩ, and 100 kΩ Compact 10-lead MSOP (3 mm × 4.9 mm) package Fast settling time: tS = 5 µs typical on power-up Full read/write of wiper register Power-on preset to midscale Computer software replaces microcontroller in factory programming applications Single supply: 2.7 V to 5.
PAGE 2
AD5162 TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 13 Applications ....................................................................................... 1 Programming the Variable Resistor and Voltage ................... 13 Functional Block Diagram ..............................................................
PAGE 3
AD5162 SPECIFICATIONS ELECTRICAL CHARACTERISTICS: 2.5 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.
PAGE 4
AD5162 ELECTRICAL CHARACTERISTICS: 10 kΩ, 50 kΩ, AND 100 kΩ VERSIONS VDD = 5 V ± 10%, or 3 V ± 10%; VA = VDD; VB = 0 V; −40°C < TA < 125°C; unless otherwise noted. Table 2.
PAGE 5
AD5162 TIMING CHARACTERISTICS: ALL VERSIONS VDD = 5 V ± 10%, or 3 V ± 10%; VA = VDD; VB = 0 V; −40°C < TA < +125°C; unless otherwise noted. Table 3.
PAGE 6
AD5162 ABSOLUTE MAXIMUM RATINGS TA = 25°C, unless otherwise noted. Table 4. Parameter VDD to GND VA, VB, VW to GND Terminal Current, Ax to Bx, Ax to Wx, Bx to Wx1 Pulsed Continuous Digital Inputs and Output Voltage to GND Operating Temperature Range Maximum Junction Temperature (TJMAX) Storage Temperature Lead Temperature (Soldering, 10 sec) Thermal Resistance, θJA for 10-Lead MSOP2 Rating –0.
PAGE 7
AD5162 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS B1 1 10 W1 9 B2 W2 3 AD5162 GND 4 TOP VIEW VDD 5 8 CS 7 SDI 6 CLK 04108-0-002 A1 2 Figure 2. Table 5. Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 Mnemonic B1 A1 W2 GND VDD CLK SDI CS B2 W1 Description B1 Terminal. A1 Terminal. W2 Terminal. Digital Ground. Positive Power Supply. Serial Clock Input. Positive-edge triggered. Serial Data Input. Chip Select Input, Active Low. When CS returns high, data is loaded into the DAC register.
PAGE 8
AD5162 TYPICAL PERFORMANCE CHARACTERISTICS 2.0 0.5 TA = 25°C RAB = 10kΩ 1.0 VDD = 2.7V 0.5 0 VDD = 5.5V –0.5 RAB = 10kΩ 0.4 POTENTIOMETER MODE DNL (LSB) –1.0 –1.5 0.3 0.2 0.1 VDD = 2.7V; TA = –40°C, +25°C, +85°C, +125°C 0 –0.1 –0.2 –0.3 32 64 96 128 160 192 224 256 CODE (DECIMAL) –0.5 04108-0-003 0 0 32 128 160 192 224 256 Figure 6. DNL vs. Code vs. Temperature 1.0 0.5 TA = 25°C RAB = 10kΩ 0.3 0.2 VDD = 2.7V 0.1 0 –0.1 –0.2 VDD = 5.5V –0.3 TA = 25°C RAB = 10kΩ 0.
PAGE 9
AD5162 2.0 4.50 RAB = 10kΩ RAB = 10kΩ 1.0 0.5 0 VDD = 5.5V TA = –40°C, +25°C, +85°C, +125°C –0.5 –1.0 –1.5 0 32 64 96 128 160 192 224 256 CODE (DECIMAL) 3.00 2.25 VDD = 2.7V, VA = 2.7V 1.50 VDD = 5.5V, VA = 5.0V 0.75 0 –40 04108-0-009 –2.0 3.75 –10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) Figure 9. R-INL vs. Code vs. Temperature Figure 12. Zero-Scale Error vs. Temperature 10 0.5 RAB = 10kΩ 0.4 0.3 0.
PAGE 10
AD5162 0 RAB = 10kΩ 0x80 –6 40 0x40 –12 30 GAIN (dB) 20 0x20 –18 VDD = 2.7V TA = –40°C TO +85°C, –40°C TO +125°C 10 0 0x10 –24 0x08 –30 0x04 –36 0x02 –42 –10 0x01 VDD = 5.5V TA = –40°C TO +85°C, –40°C TO +125°C –48 –20 0 32 64 96 128 160 192 224 256 CODE (DECIMAL) –60 1k 10k Figure 15. Potentiometer Mode Tempco ΔVWB/ΔT vs. Code 1M Figure 18. Gain vs. Frequency vs.
PAGE 11
AD5162 10 1 VDD = 5.5V VW2 0.1 VDD = 2.7V 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 DIGITAL INPUT VOLTAGE (V) 5.0 04108-0-025 0.01 04108-0-024 VW1 Figure 24. Analog Crosstalk Figure 21. Supply Current vs. Digital Input Voltage VW VW 04108-0-021 04108-0-026 CLK VW2 VW VW1 CS Figure 23. Digital Crosstalk 04108-0-023 Figure 25. Midscale Glitch, Code 0x80 to Code 0x7F Figure 22. Digital Feedthrough 04108-0-022 IDD, SUPPLY CURRENT (mA) TA = 25°C Figure 26.
PAGE 12
AD5162 TEST CIRCUITS Figure 27 through Figure 32 illustrate the test circuits that define the test conditions used in the product specification tables (see Table 1 and Table 2). VA VMS ( W V+ B ∆VMS PSRR (dB) = 20 LOG ∆VDD ∆VMS% PSS (%/%) = ∆VDD% A B Figure 27. Test Circuit for Potentiometer Divider Nonlinearity Error (INL, DNL) VMS Figure 30. Test Circuit for Power Supply Sensitivity (PSS, PSSR) NO CONNECT DUT DUT A IW A W +15V W VIN AD8610 B OFFSET GND 04108-0-028 B VMS ) –15V 2.
PAGE 13
AD5162 THEORY OF OPERATION The AD5162 is a 256-position, digitally controlled variable resistor (VR) device. The general equation determining the digitally programmed output resistance between W and B is An internal power-on preset places the wiper at midscale during power-on, which simplifies the fault condition recovery at power-up. PROGRAMMING THE VARIABLE RESISTOR AND VOLTAGE Rheostat Operation The nominal resistance of the RDAC between Terminal A and Terminal B is available in 2.
PAGE 14
AD5162 PROGRAMMING THE POTENTIOMETER DIVIDER ESD PROTECTION Voltage Output Operation All digital inputs are protected with a series of input resistors and parallel Zener ESD structures, as shown in Figure 36 and Figure 37. This applies to the SDI, CLK, and CS digital input pins. 340Ω LOGIC GND VI Figure 36. ESD Protection of Digital Pins A GND Figure 35. Potentiometer Mode Configuration Figure 37.
PAGE 15
AD5162 110 LAYOUT AND POWER SUPPLY BYPASSING TA = 25°C 106 104 102 100 98 96 94 92 90 0 5 10 15 DAYS 20 25 30 04108-0-041 Similarly, it is also good practice to bypass the power supplies with quality capacitors for optimum stability. Supply leads to the device should be bypassed with disc or chip ceramic capacitors of 0.01 μF to 0.1 μF.
PAGE 16
AD5162 SPI INTERFACE SPI-COMPATIBLE, 3-WIRE SERIAL BUS Table 8. Serial Data-Word Format1 The AD5162 contains a 3-wire, SPI-compatible digital interface (SDI, CS, and CLK). The 9-bit serial word must be loaded MSB first. The format of the word is shown in Table 8. MSB B8 A0 (28) The positive-edge sensitive CLK input requires clean transitions to avoid clocking incorrect data into the serial input register. Standard logic families work well.
PAGE 17
AD5162 OUTLINE DIMENSIONS 3.10 3.00 2.90 10 3.10 3.00 2.90 1 5.15 4.90 4.65 6 5 PIN 1 IDENTIFIER 0.50 BSC 0.95 0.85 0.75 15° MAX 1.10 MAX 0.30 0.15 6° 0° 0.23 0.13 0.70 0.55 0.40 COMPLIANT TO JEDEC STANDARDS MO-187-BA 091709-A 0.15 0.05 COPLANARITY 0.10 Figure 44. 10-Lead Mini Small Outline Package [MSOP] (RM-10) Dimensions shown in millimeters ORDERING GUIDE Model1, 2, 3 AD5162BRM2.5 AD5162BRM2.5-RL7 AD5162BRM10 AD5162BRM50 AD5162BRM50-RL7 AD5162BRM100 AD5162BRM100-RL7 AD5162BRMZ2.
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AD5162 NOTES Rev.
PAGE 19
AD5162 NOTES Rev.