ANALOG DEVICES UG-323 Service Manual
Evaluation Board User Guide
UG-323
10201-001
One Technology Way • P. O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 www.analog.com
Evaluation Board for the AD5111 Digital Potentiometer
FEATURES
Full-featured evaluation board for the AD5111
Several test circuits
Various ac/dc input signals
PC control via a separately purchased system demonstration
platform (SDP)
PC control software
PACKAGE CONTENTS
EVAL-AD511xSDZ 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 AD5111 data sheet
Electronic version of the UG-323 user guide
DIGITAL PICTURE OF EVALUATION BOARD WITH SYSTEM DEMONSTRATION PLATFORM
GENERAL DESCRIPTION
This user guide describes the evaluation board for evaluating the
AD5111—a single-channel, 128-position, nonvolatile memory
digital potentiometer.
The AD5111 supports single-supply 2.3 V to 5.5 V operation,
making the device suited for battery-powered applications and
many other applications, offering guaranteed low resistor
tolerance errors of ±8% and high bandwidth while allowing up
to ±6 mA current density in the A, B, and W pins.
A simple 3-wire up/down interface allows manual switching or
high speed digital control with clock rates up to 50 MHz.
T h e EVA L-AD5111SDZ can operate in single-supply mode and
incorporates an internal power supply from the USB.
Complete specifications for the AD5111 part can be found in
the AD5111 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 CONDITIONS.
Figure 1.
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UG-323 Evaluation Board 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
11/11—Revision 0: Initial Version
Test Circuits ...................................................................................4
Evaluation Board Software ...............................................................5
Installing the Software ..................................................................5
Running the Software ...................................................................5
Operating the Software .................................................................6
Evaluation Board Schematics and Artwork ...................................7
Ordering Information .................................................................... 11
Bill of Materials ........................................................................... 11
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Evaluation Board User Guide UG-323
+5V (from SDP).
+3V3 (from SDP).
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The EVAL-AD5111SDZ supports using single power supplies.
The evaluation board can be powered either from the SDP port
or externally by the EXTERNAL-1 and EXTERNAL-2
connectors, as described in Ta ble 2.
All supplies are decoupled to ground using 10 µF tantalum and
0.1 µF ceramic capacitors.
Table 2. Maximum and Minimum Voltages of the Connectors
Connector Number Label Voltage
EXTERNAL-1 VDD Analog positive power supply, VDD.
If connected to the SDP, it is 3.3 V to 5.5 V.
If controlled externally , it is 2.3 V to 5.5 V.
EXTERNAL-2 AGND Analog ground, AGND.
LINK OPTIONS
One link option is incorporated in the evaluation board and
should be set up before using the board. Tab le 1 describes the
position of the link to control the evaluation board by a PC, via
the SDP board, using the EVAL-AD5111SDZ. The functions of
this link option is described in detail in Tab le 3.
Table 1. Link Options Setup for SDP Control (Default)
Link No. Option
LK8 +5V
Table 3. Link Functions
Link Number Power Supply Options
LK8 VDD This link selects one of the following as the positive power supply:
EXT1 (external supply from the EXTERNAL-1 connector).
1
If the part is powered using the external connector without connecting the SDP board, +5V jumper must be connected as well.
Rev. 0 | Page 3 of 12
UG-323 Evaluation Board User Guide
10201-002
BUF-W
750Ω
12Ω
V
DD
VOUT
AC
DC
GND
AC
R9
W
A
B
A
W
B
R8
V
DD
2
V
DD
2
256
)(
RDAC
VVV
B
A
OUT
×−=
10201-003
BUF-W
750Ω
f
C
= 200Hz
12Ω
VOUT
AC
AC_INPUT
GND
AC
R9
R7
W
A
B
A
W
B
R8
V
DD
2
V
DD
2
HPF
×≈
128
log20)dB(
RDAC
nAttenuatio
TEST CIRCUITS
The E VA L -AD5111SDZ incorporates several test circuits to
evaluate the AD5111 performance.
DAC
The AD5111 can be operated as a digital-to-analog converter
(DAC), as shown in Figure 2.
AC Signal Attenuation
The AD5111 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
Table 4 shows the options available for the voltage references.
Table 4. DAC Voltage References
Term inal Link Options Description
A LK1 AC Connects Terminal A to VDD/2
DC Connects Terminal A to VDD
W BUF-W Connects Terminal W to an
output buffer
B LK6 AC Connects Terminal B to VDD/2
GND Connects Terminal B to
analog ground
The output voltage is defined in Equation 1.
(1)
where:
RDAC is the code loaded in the RDAC register.
V
is the voltage applied to Terminal A (LK1 link).
A
V
is the voltage applied to Terminal B (LK6 link)
B
However, by using the R8 and R9 external resistors, the user can
reduce the voltage of the voltage references. In this case, use the
A and B test points to measure the voltage applied to the A and
B terminals and recalculate V
and VB in Equation 1.
A
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 Table 5.
Table 5. AC Signal Attenuation Link Options
Term inal Link Options Description
A LK1 AC Remove dc voltage and biased
the signal to V
/2
DD
W BUF-W Connects Terminal W to an
output buffer
B LK6 AC1 Connects Terminal B to VDD/2
GND Connects Terminal B to analog
ground
1
Recommended to ensure optimal total harmonic distortion (THD) performance.
The signal attenuation is defined in Equation 2.
(2)
where:
RDAC is the code loaded in the RDAC register.
In addition, R7 can be used to achieve an exponential attenuation. To do so, adjust the R7 resistor until a desirable transfer
function is found, typically around 1.6 kΩ for a 10 kΩ
potentiometer.
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