ANALOG DEVICES UG-348 Service Manual

EVAL-AD5162SDZ User Guide

UG-348

EVAL-AD5162SDZ

SYSTEM DEMONSTRATION

PLATFORM

10366-001

One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: [phone] • Fax: [phone] • www.analog.com

Evaluation Board for the AD5162 Digital Potentiometer

FEATURES

Full-featured evaluation board for the AD5162
Various test circuits
Various ac/dc input signals
PC control via a separately purchased system demonstration

platform (SDP-B)

PC software for control

PACKAGE CONTENTS

EVAL-AD5162SDZ 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 AD5162 data sheet
Electronic version of the UG-348 user guide

DIGITAL PICTURE OF EVALUATION BOARD WITH SYSTEM DEMONSTRATION PLATFORM

GENERAL DESCRIPTION

This user guide describes the evaluation board for evaluating the

AD5162, a dual-channel, 256-position digital potentiometer.

The AD5162 supports a single-supply 2.7 V to 5.5 V operation,
making the device suitable for battery-powered applications and
many other applications. In addition, the AD5162 uses a versa­tile SPI-compatible serial interface, allowing speeds of up
to 25 MHz.

The EVA L-AD5162SDZ can operate in single-supply mode and
incorporates an internal power supply from the USB.

Complete specifications for the AD5162 part can be found in
the AD5162 data sheet, which is available from Analog Devices,
Inc., and should be consulted in conjunction with this user
guide when using the evaluation board.

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITI ONS.

Figure 1.

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UG-348 EVAL-AD5162SDZ User Guide

TABLE OF CONTENTS

Features .............................................................................................. 1

Package Contents .............................................................................. 1

General Description ......................................................................... 1

Digital Picture of Evaluation Board with System

Demonstration Platform.................................................................. 1

Revision History ............................................................................... 2

Evaluation Board Hardware ............................................................ 3

Power Supplies .............................................................................. 3

Link Options ................................................................................. 3

REVISION HISTORY

12/11—Revision 0: Initial Version

Test Circuits ...................................................................................4

Evaluation Board Software ...............................................................6

Installing the Software ..................................................................6

Running the Software ...................................................................6

Software Operation .......................................................................7

Evaluation Board Schematics and Artwork ...................................8

Ordering Information .................................................................... 14

Bill of Materials ........................................................................... 14

Related Links ............................................................................... 15

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EVAL-AD5162SDZ User Guide UG-348

EXT (external supply from the J1-1 connector).

EVALUATION BOARD HARDWARE

POWER SUPPLIES

The EVA L-AD5162SDZ supports using single power supplies.

The evaluation board can be powered either from the SDP-B
port or externally by the J1-1 and J1-2 connectors, as described
in Tabl e 1.

All supplies are decoupled to ground using 10 µF tantalum and

0.1 µF ceramic capacitors.

Table 1. Maximum and Minimum Voltages of the Connectors

Connector No. Label Voltage

J1-1 EXT Analog positive power supply, VDD.
VDD

J1-2 GND Analog ground.

Table 3. Link Functions

Link No. Power Supply Options

A25 VDD This link selects one of the following as the positive power supply:
+5V (from SDP-B).
+3.3V (from SDP-B).

For single-supply operation, it is 2.7 V
to 5 V.

LINK OPTIONS

Several link and switch options are incorporated in the
evaluation board and should be set up before using the board.
Tabl e 2 describes the positions of the links to control the
evaluation board by a PC, via the SDP-B board, using the EVA L -

AD5162SDZ in single-supply mode. The functions of these link

options are described in detail in Table 3 through Ta bl e 6.

Table 2. Link Options Setup for SDP-B Control (Default)

Link No. Option
A25 +3.3V
A24 GND

A24 VSS This link should be connected to GND (analog ground).

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UG-348 EVAL-AD5162SDZ User Guide

256

)(

WB1

B1

A1

OUT

R

VVV ×−=















+

×=

−− ENDTOEND

WWB1

R

RR

nAttenuatio log20)dB(

W1_BUF

A1

RDAC1

AC + DC

VDD

A1

B1

BUF_W1

GND

DC

2

V

DD

– V

SS

V

DD

2

V

DD

– V

SS

R34

R35

W1

W1

B1

10366-002

W1_BUF

A1

RDAC1

AC + DC

AC_INPUT

AC

A1

B1

BUF_W1

GND

2

V

DD

– V

SS

R34

R35

W1

W1

B1

1µF

R36

DC

2

V

DD

– V

SS

10366-003

TEST CIRCUITS

The EVA L-AD5162SDZ incorporates several test circuits to
evaluate the AD5162 performance.

DAC

RDAC1 can be operated as a digital-to-analog converter (DAC),
as shown in Figure 2.

AC Signal Attenuation

RDAC1 can be used to attenuate an ac signal, which must be
provided externally using the AC_INPUT connector, as shown
in Figure 3.

Figure 2. DAC

Tabl e 4 shows the options available for the voltage references.

Table 4. DAC Voltage References

Terminal Link Options Description

A1 A20 AC + DC

Connects Terminal A1 to

(VDD − VSS)/2.
VDD Connects Terminal A1 to VDD.
W1 BUF_W1

Connects Terminal W1 to an

output buffer.
B1 A21 DC

Connects Terminal B1 to

(VDD − VSS)/2.
GND

Connects Terminal B1 to

analog ground.

The output voltage is defined in Equation 1.

(1)

where:

is the resistor between the W1 and B1 terminals.

R

WB1

V

is the voltage applied to the A1 terminal (A20 link).

A1

is the voltage applied to the B1 terminal (A21 link).

V

B1

Howe ver, by using the R34 and R35 external resistors, the user
can reduce the voltage of the voltage references. In this case, use
the A1 and B1 test points to measure the voltage applied to the
A0 and B0 terminals and recalculate V

and VB0 in Equation 1.

A0

Figure 3. AC Signal Attenuator

Depending on the voltage supply rails and the dc offset voltage
of the ac signal, various configurations can be used as described
in Tabl e 5.

Table 5. AC Signal Attenuation Link Options

Link Options Conditions

A20 AC + DC No dc offset voltage.

AC signal is outside the voltage supply rails

due to the dc offset voltage.
DC offset voltage ≠ VDD/2.1
AC All other conditions.
A21 DC Use in conjunction with ac + dc link.
GND All other conditions.

1

Recommended to ensure optimal total harmonic distortion (THD) performance.

The signal attenuation is defined in Equation 2.

(2)

where:

R

is the resistor between the W1 and B1 terminals.

WB1

R

is the wiper resistance.

W

R

END-TO-END

is the end-to-end resistance value.

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.

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EVAL-AD5162SDZ User Guide UG-348

R38

R

G

WB2

+=1

R38

R

G

WB2

−=

Noninverting

Linear

A27

LINEAR

0 V to VDD

Inverting

Linear

A27

LINEAR

−VDD to 0 V

V

IN

RDAC2

B2

R42

W2

B2

W2

V

OUT

OAVOUT

C1

10nF

R41

1.7kΩ

R38

2.7kΩ

10366-004

V

IN

RDAC2

B2

R42

W2

B2

W2

V

OUT

OAVOUT

C1

10nF

R41

1.7kΩ

R38

2.7kΩ

10366-006

Signal Amplifier

RDAC2 can be operated as an inverting or noninverting signal
amplifier supporting linear or pseudologarithmic gains. Tab l e 6
shows the available configurations.

The noninverting amplifier with linear gain is shown in Figure 4,
and the gain is defined in Equation 3.

(3)

The inverting amplifier with linear gain is shown in Figure 5,
and the gain is defined in Equation 4.

Note that the input signal, V

, must be negative.

IN

(4)

where R

is the resistor between the W2 and B2 terminals.

WB2

where R

is the resistor between the W2 and B2 terminals.

WB2

Figure 5. Linear Inverting Amplifier

Figure 4. Linear Noninverting Amplifier

R42 can be used to set the maximum and minimum gain limits.

Table 6. Amplifier Selection Link Options

Amplifier Gain Link Label V

A29 NON-INV
A30 NON-INV

A29 INV
A30 INV

Range

IN

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