ANALOG DEVICES UG-256 Service Manual
Evaluation Board User Guide
UG-256
AD5780
AD8675
INV
EXT
+10V
+5V
–5V
–10V
0V
EXT
R
FB
V
REFP
V
OUT_BUF
V
OUT
09726-001
V
REFN
V
OUT
PIN HEADER (J3)
SYSTEM
DEVELOPMENT
PLATFORM BOARD
PC
USB
PORT
POWER SUPPLY INPUTS
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 a 18-Bit Serial Input, Voltage Output DAC with Integrated
Precision Reference Buffer Amplifiers
FEATURES
Full-featured evaluation board for the AD5780
Link options
PC control in conjunction with Analog Devices, Inc., system
development platform
PC software for control
EVALUATION BOARD DESCRIPTION
The EVAL-AD5780 is a full-featured evaluation board, designed
to allow the user to easily evaluate all features of the AD5780
voltage output, 18-bit digital-to-analog converter (DAC). The
AD5780 pins are accessible at on-board connectors for external
connection. The board can be controlled by two means: via the
on-board connector (J3), or via the system development platform
connector (J4). The SDP board allows the evaluation board to be
controlled through the USB port of a Windows® XP- (SP2 or later)
or Vista-based (32-bit) PC using the AD5780 evaluation software.
DEVICE DESCRIPTION
The AD5780 is a high precision, 18-bit DAC with integrated
precision reference buffer amplifiers designed to meet the
requirements of precision control applications. The output
range of the AD5780 is configured by two reference voltage
inputs. The device is specified to operate with a dual power
supply of up to 33 V.
Complete specifications for the AD5780 are provided in the
AD5780 data sheet, available from Analog Devices, 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.
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
Rev. A | Page 1 of 20
UG-256 Evaluation Board User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Evaluation Board Description......................................................... 1
Device Description ........................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Evaluation Board Hardware ............................................................ 3
Power Supplies .............................................................................. 3
Link Options ................................................................................. 3
On-Board Connectors ................................................................. 3
REVISION HISTORY
7/12—Rev. 0 to Rev. A
Changed ADR445 to ADR4550 (Throughout) ............................ 3
Changes to Evaluation Board Schematics and Artwork Section . 9
11/11—Revision 0: Initial Version
Evaluation Board Software ...............................................................5
Software Installation .....................................................................5
Software Operation .......................................................................5
Main Window ................................................................................6
Evaluation Board Performance ........................................................8
Evaluation Board Schematics and Artwork ...................................9
Ordering Information .................................................................... 15
Bill of Materials ........................................................................... 15
Rev. A | Page 2 of 20
Evaluation Board User Guide UG-256
LK3
A
LK8
C
10 8 6 4 2
6
J2
Analog power supply connector
EVALUATION BOARD HARDWARE
POWER SUPPLIES
The following external supplies must be provided:
• 5 V between the V
and DGND inputs for the digital
CC
supply of the AD5780. Alternatively, place Link 1 in
Position A to power the digital circuitry from the USB
port via the SDP board (default).
• 7.5 V to 16.5 V between the V
and AGND inputs for
DD
the positive analog supply of the AD5780.
• −2.5 V to −16.5 V between the V
and AGND inputs for
SS
the negative analog supply of the AD5780.
The analog and digital planes are connected at one location, close
to the AD5780. To avoid ground loop problems, it is recommended
not to connect AGND and DGND elsewhere in the system.
Each supply is decoupled to the relevant ground plane with 10 µF
and 0.1 µF capacitors. Each device supply pin is again decoupled
with a 10 µF and 0.1 µF capacitor pair to the relevant ground plane.
LINK OPTIONS
The link options on the evaluation board should be set for the
required operating setup before using the board. The functions
of the link options are described in Tabl e 5.
Default Link Option Setup
The default link options are listed in Table 1. By default, the
board is configured with V
a ±10 V output range.
Table 1. Default Link Options
Link No. Option
LK1 A
LK2 B
LK4 Removed
LK5 Removed
LK6 Removed
LK7 Removed
LK9 Inserted
LK11 Inserted
= +10 V and V
REFP
= −10 V for
REFN
Connector J3 Pin Descriptions
Table 2. Connector J3 Pin Configuration
9 7 5 3 1
Table 3. Connector J3 Pin Descriptions
Pin No. Description
1 SDO
2
3 DGND
4
5 DGND
7 SDIN
8 DGND
9 SCLK
10
RESET
CLR
LDAC
SYNC
ON-BOARD CONNECTORS
There are nine connectors on the AD5780 evaluation board
PCB as outlined in Table 4.
Table 4. On-Board Connectors
Connector Function
J1 Digital power supply connector
J3 Digital interface pin header connector
J4 SDP board connector
VOUT DAC output connector
VOUT_BUF Buffered DAC output connector
VREF +5 V external reference voltage input connector
(+10 V, +5 V, −10 V, and −5 V reference voltages are
generated from this +5 V input or on-board
ADR4550)
VREFN DAC negative reference input connector
VREFP DAC positive reference input connector
Rev. A | Page 3 of 20
UG-256 Evaluation Board User Guide
Position A configures the amplifier in unity gain. LK4 should be removed.1
When this link is inserted,
is at logic low.
Position A selects an on-board generated −5 V.
Table 5. Link Options
Link No. Description
LK1 This link selects the source of the digital power supply.
Position A selects the source from the SDP board.
Position B selects the source from Connector J1.
LK2 This link selects the positive reference voltage source.
Position A selects an on-board generated +5 V.
Position B selects an on-board generated +10 V.
Position C selects an external voltage applied at Connector VREFP.
LK3 This link is used in conjunction with LK4 to configure the mode of operation of the output amplifier.
Position B configures the amplifier for a gain of 2. Lk4 should be inserted.2
LK4 This link is used in conjunction with LK3 to configure the mode of operation of the output amplifier.
When this link is inserted, LK3 should be in Position B to configure the amplifier for a gain of 2.2
When this link is removed, LK3 should be in Position A to configure the amplifier for unity gain.1
LK5 This link selects the state of the
When this link is inserted,
When this link is removed,
RESET
RESET
LK6 This link selects the state of the
When this link is inserted,
When this link is removed,
is at logic low.
CLR
CLR
LK7 This link selects the state of the
LDAC
When this link is removed,
LDAC
LK8 This link selects the negative reference voltage source.
pin.
RESET
is at logic low.
is at logic high.
pin.
CLR
is at logic high.
pin.
LDAC
is at logic high.
Position B selects AGND.
Position C selects an on-board generated −10 V.
Position D selects an external voltage applied at Connector VREFN.
LK9 This link connects the output of Voltage Reference U5 to the reference scaling circuitry.
LK11 This link connects the DAC output to the noninverting input of the output buffer amplifier.
When this link is inserted, the DAC output is connected to the noninverting input of the output amplifier.
When this link is removed, the DAC output is disconnected from the noninverting input of the output buffer amplifier and the
DAC output voltage is accessible at the VOUT connector.
1
The RBUF bit of the control register must be set to high to enable the unity gain mode of operation.
2
The RBUF bit of the control register must be cleared to low to enable the gain of 2 mode of operation.
Rev. A | Page 4 of 20
Evaluation Board User Guide UG-256
09726-002
09726-003
EVALUATION BOARD SOFTWARE
SOFTWARE INSTALLATION
The AD5780 evaluation kit includes self-installing software on
a CD. The software is compatible with Windows XP (SP2) and
Vista (32-bit). If the setup file does not run automatically, you
can run the setup.exe file from the CD.
Install the evaluation software before connecting the evaluation
board and SDP board to the USB port of the PC to ensure that
the evaluation system is correctly recognized when connected to
the PC.
1. After installation from the CD is complete, power up the
AD5780 evaluation board as described in the Power Supplies
section. Connect the SDP board (via either Connector A or
Connector B) to the AD5780 evaluation board and then
to the USB port of your PC using the supplied cable.
2. When the evaluation system is detected, proceed through any
dialog boxes that appear. This completes the installation.
SOFTWARE OPERATION
To launch the software, complete the following steps:
1. From the Start menu, select Analog Devices – AD5780 >
AD5780 Evaluation Software. The main window of the
software then displays (see Figure 3).
2. If the evaluation system is not connected to the USB port
when the software is launched, a connectivity error displays
(see Figure 2). Connect the evaluation board to the USB
port of the PC, wait a few seconds, click Rescan, and follow
the instructions.
Figure 2. Connectivity Error Alert
Figure 3. Main Window
Rev. A | Page 5 of 20
UG-256 Evaluation Board User Guide
09762-004
09726-005
MAIN WINDOW
The main window is divided into three tabs: Configure,
Program Voltage, and Measure DAC Output.
Configure
The Configure section allows access to the control register,
clearcode register, software control register, and DAC register
and also allows control of the
RESET, CLR
Program Voltage
The Program Voltage section programs the DAC register with
a value calculated from the entered values: the positive voltage
reference (VREFP), the negative voltage reference (VREFN),
and the desired output voltage (see Figure 4).
, and
LDAC
pins.
To begin the measurement, click START. The measurement can
be halted at any time by clicking STOP. When the measurement
is completed, a dialog box appears to allow the data to be saved
as a spreadsheet file with three columns of data. The first column is
the DAC code, the second column is the DAC voltage in volts,
and the third column is the INL error in LSBs, as shown in
Figure 5. A graph of both the DAC output voltage vs. the DAC
code and the INL error vs. the DAC code is displayed on-screen
(see Figure 6). In the measurement example shown in Figure 6,
measurements are taken in 1024 code steps beginning at Code 0
and finishing at Code 262,143 in total 256 measurements. With
the number of power line cycles (NPLC) setting on the multimeter
set to 1, the measurement takes ~18 sec to complete. To complete
an all codes measurement requiring 262,144 measurement
points takes ~6 hours to complete.
Figure 4. Program Voltage Window
Measure DAC Output
The Measure DAC Output section allows the PC to control an
Agilent 3458A multimeter to measure and log the DAC output
voltage.
The multimeter is controlled over a general-purpose interface
bus (GPIB). Once connected to the PC, first configure the
multimeter via its front panel before taking a measurement.
Figure 6 shows the measurement options. The software runs
through a sequence of steps, programming the DAC register
and measuring the DAC output voltage. The sequence begins
with the software programming the DAC with the Start Code
value, incrementing the programmed value at each step by the
Code Step value, and finishing when the programmed value
reaches the Stop Code value. A delay between measurements
can be inserted, if required. The GPIB address of the multimeter
must be specified.
Figure 5. Saved Data Format
If an Agilent 3458A multimeter is not connected to the PC,
the software steps through the codes without taking any
measurements.
Rev. A | Page 6 of 20
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