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Evaluation Board User Guide

UG-258

One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Te l: 781.329.4700 • Fax: 781.461.3113 • www.analog.com

Evaluation Board for the AD5235 Digital Potentiometer

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT

WARNING AND LEGAL TERMS AND CONDITIONS.

Rev. 0 | Page 1 of 16

FEATURES

Full featured evaluation board for the AD5235

Several test circuits

Various ac/dc input signals

PC control via a separately purchased system demonstration

platform (SDP)

PC control software

26 extra bytes in EEMEM for user-defined information

Resistor tolerance error stored in EEMEM

PACKAGE CONTENTS

EVAL-AD5235SDZ evaluation board

CD that includes

Self-installing software that allows users to control the

board and exercise all functions of the device

Electronic version of the AD5235 data sheet

Electronic version of the UG-258 document

GENERAL DESCRIPTION

This user guide describes the evaluation board for evaluating the

AD5235—a dual-channel, 1024-position, nonvolatile memory

digital potentiometer. With versatile programmability, the AD5235

allows multiple modes of operation, including read/write access

in the RDAC and EEMEM registers, increment/decrement of

resistance, resistance changes in ±6 dB scales, wiper setting read-

back, and extra EEMEM for storing user-defined information,

such as memory data for other components or a lookup table.

The AD5235 supports dual-supply ±2.25 V to ±2.75 V operation

and single-supply 2.7 V to 5.5 V operation, making the device

suited for battery-powered applications and many other appli-

cations. In addition, the AD5235 uses a versatile SPI-compatible

serial interface, allowing speeds of up to 50 MHz .

The EVAL-AD5235SDZ can operate in single-supply and dual-

supply mode and incorporates an internal power supply from

the USB.

Complete specifications for the AD5235 part can be found in

the AD5235 data sheet, which is available from Analog Devices,

Inc., and should be consulted in conjunction with this user

guide when using the evaluation board.

DIGITAL PICTURE OF EVALUATION BOARD WITH SYSTEM DEMONSTRATION PLATFORM

EVAL-AD5235SDZ

SYSTEM DEMONSTRATION

PLATFORM

09728-001

Figure 1.

Summary of content (16 pages)

PAGE 1
Evaluation Board User Guide UG-258 One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.
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UG-258 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Test Circuits ...................................................................................4 Package Contents.............................................................................. 1 Evaluation Board Software...............................................................6 General Description .........................................
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Evaluation Board User Guide UG-258 EVALUATION BOARD HARDWARE POWER SUPPLIES LINK OPTIONS The EVAL-AD5235SDZ supports the use of single and dual power supplies. Several link and switch options are incorporated into the evaluation board and should be set up before using the board. Table 2 describes the positions of the links to control the evaluation board by a PC, via the SDP board, using the EVAL-AD5235SDZ in single-supply mode.
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UG-258 Evaluation Board User Guide TEST CIRCUITS 1µF The EVAL-AD5235SDZ incorporates several test circuits to evaluate the AD5235 performance. VDD – VSS 2 AC + DC AC AC_INPUT R34 A1 DAC RDAC1 RDAC1 can be operated as a digital-to-analog converter (DAC), as shown in Figure 2. W1 B1 AC + DC R36 B1 VDD R34 A1 RDAC1 VDD – VSS W1 A1 W1 2 VSS VSS VSS Table 4. DAC Voltage References BUF-W1 B1 A21 GND Table 5.
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Evaluation Board User Guide UG-258 In addition, R36 can be used to achieve a pseudologarithmic attenuation. To do so, adjust the R36 resistor until a desirable transfer function is found. R41 1.7kΩ VIN VOUT RDAC2 can be operated as an inverting or noninverting signal amplifier supporting linear or pseudologarithmic gains. Table 6 shows the available configurations.
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UG-258 Evaluation Board User Guide EVALUATION BOARD SOFTWARE INSTALLING THE SOFTWARE RUNNING THE SOFTWARE The EVAL-AD5235SDZ evaluation kit includes evaluation board software provided on a CD. The software is compatible with Windows® XP, Windows Vista, and Windows 7 (both 32 and 64 bits). To run the evaluation board software, do the following: 1. 2. Install the software before connecting the SDP board to the USB port of the PC to ensure that the SDP board is recognized when it is connected to the PC.
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Evaluation Board User Guide UG-258 SOFTWARE OPERATION The main window of the EVAL-AD5235SDZ software is divided into the following sections: QUICK COMMANDS, REGISTER ACCESS, HARDWARE PINS, TOLERANCE, and MEMORY. The features of the main window are as follows: • • The QUICK COMMANDS section allows you to send the AD5235 quick commands directly to the AD5235. The REGISTER ACCESS section can be used to update the RDAC registers by typing a value into a window and clicking WRITE.
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A1 A1 Rev. 0 | Page 8 of 16 Figure 10.
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Evaluation Board User Guide UG-258 VDD 8 U15-C V+ V4 VDD VSS R39 AC_INPUT A1 C3 A20 U15-A 3 2 R40 A + 1 B C - VDD AC + DC AC R34 A1 AD8652AR VSS DAC + FLOATING DAC + BW W1-1 W1-2 W1-3 W1-4 W1-5 W1-6 W1-7 W1-8 W1-9 W1-10 W1-11 W1-12 AD8403-1 W1_BUF BUF-W1 AD5204-1 3 + 1 U14-A 2 AD8618ARZ AD5233-1 W1 AD5162-1 AD5232-1 ADN2850-1 W1 AD5235-1 R36 AD5254-1 PSEUDOLOG ATTENUATOR AD5252-1 AD5172 AD5243-1 B1 AD5222-1 A21 A VDD B1 R35 B1 B R3 C VSS 6 5 AD8652AR - 7 + U15-B 09
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Rev. 0 | Page 10 of 16 W3-8 W3-3 W3-2 W3-1 AD5254-4 AD5233-4 AD5204-4 AD8403-4 AD5254-3 AD5233-3 AD5204-3 AD8403-3 W4-8 W4-3 W4-2 W4-1 W3 W4 BUF-3 BUF-4 A3 B4 A4 B3 10 + 8 U14-C 9 AD8618ARZ 12 + 14 U14-D 13 AD8618ARZ CHANNELS 3 AND 4 B3 VOUT3 A3 B4 VOUT4 A4 O1 Figure 13. Schematic of AD5235 Power Supplies and Other Channels O2 O2 O1 DIGITAL PINS +3.3V +5V GND GND EXT VSS B A A24 + V1 V2 V2 V1 + 10uF C27 C24 10uF C26 0.1uF C25 0.
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+3.3V 24LC01 1 A0 2 A1 3 A2 4 VSS D6 LED U25 8 VCC 7 WP 6 SCL 5 SDA 1K R37 Rev. 0 | Page 11 of 16 RESET_BF SHDN_BF MUX-A0|CS MUX-A2|U/D SCL_BF SDA_BF DIN_BF SCLK_BF SYNC_BF +5V +3.3V J22 Figure 14.
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Evaluation Board User Guide 09728-014 UG-258 09728-012 Figure 15. Component Side View 09728-016 Figure 16. Component Placement Drawing Figure 17. Layer 2 Side PCB Drawing Rev.
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UG-258 09728-015 Evaluation Board User Guide 09728-013 Figure 18. Layer 3 Side PCB Drawing Figure 19. Solder Side PCB Drawing Rev.
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UG-258 Evaluation Board User Guide ORDERING INFORMATION BILL OF MATERIALS Table 7.
PAGE 15
Evaluation Board User Guide UG-258 NOTES Rev.
PAGE 16
UG-258 Evaluation Board User Guide NOTES I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). ESD Caution ESD (electrostatic discharge) sensitive device. Charged devices and circuit boards can discharge without detection. Although this product features patented or proprietary protection circuitry, damage may occur on devices subjected to high energy ESD.