EVAL-AD7902SDZ User Guide
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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
Evaluating the AD7902 Dual Pseudo Differential, 16-Bit, 1 MSPS PulSAR ADC
FEATURES
ADDITIONAL EQUIPMENT/SOFTWARE NEEDED
Full featured evaluation board for the AD7902
Versatile analog signal conditioning circuitry
On-board reference, reference buffers, and ADC drivers
System demonstration board compatible (EVAL-SDP-CB1Z)
PC software for control and data analysis of time and
frequency domain
System demonstration platform (EVAL-SDP-CB1Z)
Precision analog signal source
Power supply, +7 V/−2.5 V (optional)
USB cable
SMA cable
PC running Windows XP SP2, Windows Vista, Windows 7, or
higher with USB 2.0 port
Evaluation software for the AD7902 (download from
AD7902 product page)
EVALUATION KIT CONTENTS
EVAL-AD7902SDZ evaluation board
Wall power supply 9 V dc adapter
Daughter card power connector
ONLINE RESOURCES
Documents Needed
AD7902 data sheet
EVAL-AD7902SDZ user guide
Required Software
EVAL-AD7902SDZ evaluation software
FAQs and Troubleshooting
TYPICAL SETUP
SMA
CONNECTOR
SIGNAL SOURCE
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PC
Figure 1. Typical Setup for the EVAL-AD7902SDZ
(EVAL-AD7902SDZ on Left and EVAL-SDP-CB1Z on Right)
PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.
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EVAL-AD7902SDZ User Guide
TABLE OF CONTENTS
Features .............................................................................................. 1
Modes of Operation ....................................................................... 12
Evaluation Kit Contents ................................................................... 1
SDP Controlled Mode ............................................................... 12
Additional Equipment/Software Needed ...................................... 1
Standalone Mode ........................................................................ 12
Online Resources .............................................................................. 1
How to Use the Software ............................................................... 13
Typical Setup ..................................................................................... 1
Revision History ............................................................................... 2
Setting Up the System for Data Capture:
Board Operation/Connection Sequence ................................. 13
General Description ......................................................................... 3
Starting the Software .................................................................. 13
Getting Started .................................................................................. 4
Overview of the Main Window ................................................ 15
Software Installation Procedures ................................................ 4
Generating a Waveform Analysis Report................................ 16
Evaluation Board Setup Procedures........................................... 7
Generating a Histogram of the ADC Code Distribution ..... 17
Evaluation Board Hardware ............................................................ 8
Generating a Fast Fourier Transform of AC Characteristics ...... 18
Device Description ....................................................................... 8
Generating a Summary of the Waveform, Histogram, and
Fast Fourier Transform .............................................................. 19
Power Supplies .............................................................................. 8
Link Configuration Options ......................................................... 10
Evaluation Board Circuitry ........................................................... 11
Analog Inputs .............................................................................. 11
Reference ..................................................................................... 11
Serial Interface ............................................................................ 11
Evaluation Board Schematics and Artwork ................................ 20
EVAL-AD7902SDZ Schematics ............................................... 20
EVAL-AD7902SDZ Layout ....................................................... 26
Bill of Materials ............................................................................... 29
Related Links ................................................................................... 31
REVISION HISTORY
2/14—Revision 0: Initial Version
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GENERAL DESCRIPTION
The EVAL-AD7902SDZ is an evaluation board designed to
demonstrate the low power AD7902 performance and to
provide an easy to understand interface for a variety of system
applications. The AD7902 is a dual pseudo differential 16-bit,
1 MSPS PulSAR® ADC. A full description of the AD7902 is
available in the AD7902 data sheet and should be consulted
when using this evaluation board.
The evaluation board is ideal for use with the Analog Devices, Inc.,
system demonstration platform (SDP) board, EVAL-SDP-CB1Z.
The evaluation board interfaces to the SDP board via a 120-pin
connector. SMA Connectors J6, J10, J14, and J15 are provided
to connect a low noise analog signal source.
The user PC software executable controls the evaluation board
over the USB through the SDP board, EVAL-SDP-CB1Z.
On-board components include the following:
ADR435: high precision, buffered band gap 5.0 V reference
AD8031: reference buffer
ADA4841-1: signal conditioning circuit with op amps
ADP7104 and ADP2301: regulators to derive necessary voltage
levels on board
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GETTING STARTED
4.
SOFTWARE INSTALLATION PROCEDURES
Download the evaluation board software from the AD7902
product page on the Analog Devices website, at
www.analog.com.
There are two parts to the installation:
•
•
Select the location to install the software, and then click
Next. (The default location is C:\Program Files (x86)\
Analog Devices\AD7902_03 Evaluation Software\.
This location also contains the executable software and
example files.)
AD7902 evaluation board software installation
EVAL-SDP-CB1Z system demonstration platform board
drivers installation
Warning
Install the evaluation board software and drivers before
connecting the evaluation board and EVAL-SDP-CB1Z board to
the USB port of the PC to ensure that the evaluation system is
correctly recognized when it is connected to the PC.
Installing the AD7902 Evaluation Board Software
To install the AD7902 evaluation board software,
Figure 3. AD7902 Evaluation Board Software Installation:
Selecting the Location for Software Installation
(the Default Location Is Shown)
5.
A license agreement appears. Read the agreement, and then
select I accept the License Agreement and click Next.
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2.
3.
Start the Windows operating system and download the
software from the AD7902 product page on the Analog
Devices website, at www.analog.com.
Unzip the downloaded file.
Double-click the setup.exe file to begin the evaluation
board software installation (see Figure 2).
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1.
Figure 2. AD7902 Evaluation Board Software Installation: Installation Begins
Figure 4. AD7902 Evaluation Board Software Installation:
Accepting the License Agreement
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8.
The dialog box informs you when the installation is
complete. Click Next.
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A summary of the installation is displayed. Click Next to
continue.
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6.
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Figure 7. AD7902 Evaluation Board Software Installation:
Indicating When the Installation Is Complete
Figure 5. AD7902 Evaluation Board Software Installation:
Reviewing a Summary of the Installation
9.
The setup for the installation of the EVAL-SDP-CB1Z
system demonstration platform board drivers automatically begins to load.
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A dialog box shows the installation progress.
Figure 8. Loading the Setup for SDP Drivers Installation
Installing the EVAL-SDP-CB1Z System Demonstration
Platform Board Drivers
After the installation of the evaluation board software is complete,
a welcome window is displayed for the installation of the EVALSDP-CB1Z system demonstration platform board drivers.
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1.
Make sure that all other applications are closed, and then
click Next.
Figure 6. AD7902 Evaluation Board Software Installation:
Displaying Installation Progress
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7.
Figure 9. EVAL-SDP-CB1Z Drivers Setup:
Beginning the Drivers Installation
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Select the location to install the drivers, and then click Install.
5.
To complete the drivers installation, click Finish, which
closes the installation wizard.
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2.
EVAL-AD7902SDZ User Guide
Figure 10. EVAL-SDP-CB1Z Drivers Setup:
Selecting the Location for Drivers Installation
3.
Figure 13. EVAL-SDP-CB1Z Drivers Setup:
Completing the Drivers Setup Wizard
Installation of the SDP drivers begins.
Before using the evaluation board, you must restart your
computer. A dialog box opens, giving you the following
options: Restart, Shut Down, Restart Later. Click the
appropriate button.
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6.
Figure 11. EVAL-SDP-CB1Z Drivers Setup:
Beginning the Installation
A dialog box appears asking whether you would like to
install this device software. Click Install to confirm that
you would like to install the drivers.
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4.
Figure 12. EVAL-SDP-CB1Z Drivers Setup:
Granting Permission to Install Drivers
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Figure 14. EVAL-SDP-CB1Z Drivers Setup:
Restarting the Computer
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EVALUATION BOARD SETUP PROCEDURES
Verifying the Board Connection
The AD7902 evaluation board connects to the (EVAL-SDP-CB1Z)
system demonstration board. The EVAL-SDP-CB1Z board is
the controller board, which is the communication link between
the PC and the main evaluation board.
1.
Figure 1 shows a photograph of the connections made between
the EVAL-AD7902SDZ daughter board and the EVAL-SDP-CB1Z
motherboard.
2.
Connecting the Evaluation and SDP Boards to a PC
2.
3.
4.
Install the AD7902 software. Ensure that the EVAL-SDPCB1Z board is disconnected from the USB port of the PC
while installing the software. The PC must be restarted
after the installation is complete.
Before connecting power, connect the 120-pin connector, J5,
of the EVAL-AD7902SDZ board to Connector J4 on the
EVAL-SDP-CB1Z board. Nylon screws are included in the
EVAL-AD7902SDZ evaluation kit and can be used to
ensure that the EVAL-AD7902SDZ and EVAL-SDP-CB1Z
boards are connected firmly together.
Connect the 9 V power supply adapter included in the kit
to the EVAL-SDP-CB1Z.
Connect the EVAL-SDP-CB1Z board to the PC via the
USB cable. (If you are using Windows® XP, you may need to
search for the EVAL-SDP-CB1Z drivers. Choose to automatically search for the drivers for the EVAL-SDP-CB1Z
board if prompted by the operating system.)
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1.
Allow the Found New Hardware Wizard to run after the
EVAL-SDP-CB1Z board is plugged into your PC. (If you
are using Windows XP, you may need to search for the
EVAL-SDP-CB1Z drivers. Choose to automatically search
for the drivers for the EVAL-SDP-CB1Z board if prompted
by the operating system.)
Check that the board is connected to the PC correctly
using the Device Manager of the PC.
a. Access the Device Manager as follows:
i. Right-click My Computer and then click Manage.
ii. A dialog box appears asking for permission to
allow the program to make changes to your
computer. Click Yes.
iii. The Computer Management box appears. From
the list of System Tools, click Device Manager.
b. Under ADI Development Tools, Analog Devices
System Development Platform SDP-B should appear
(see Figure 15), indicating that the EVAL-SDP-CB1Z
driver software is installed and that the board is
connected to the PC correctly.
Figure 15. Device Manager:
Checking that the Board Is Connected to the PC Correctly
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EVALUATION BOARD HARDWARE
DEVICE DESCRIPTION
The AD7902 is a 16-bit, 1 MSPS, precision, power efficient, dual
pseudo differential PulSAR ADC that uses SAR-based
architecture and does not exhibit any pipeline delay or latency.
The AD7902 is specified for use with a single supply of 2.5 V
(VDD1, VDD2). The interface from the digital host to the
AD7902 uses 1.8 V/2.5 V/3.3 V/5.5 V logic. The AD7902 is
compatible with the SPI/QSPI/MICROWIRE/DSP serial
interface to transfer data conversions. Complete AD7902
specifications are provided in the AD7902 data sheet and
should be consulted in conjunction with this user guide when
using the evaluation board. Full details on the EVAL-SDPCB1Z are available on the Analog Devices website, at
www.analog.com.
Figure 26 to Figure 31 show the evaluation board schematics.
The board consists of an AD7902 ADC (U1) with a reference
(U6—ADR435), and two ADC drivers (U12 and U17—
ADA4841-1YRZ). The evaluation board is a flexible design that
enables you to adjust compensation components and operate
the evaluation board from an adjustable bench top power supply.
Each on-board power supply is decoupled where it enters the
board as well as where it connects to each device. A single ground
plane is used on this board to minimize the effect of high frequency
noise interference.
Alternatively, the board can be powered from a bench top power
supply by using the J2 and J3 screw terminals and changing the
SL1 to SL4 and LK3 to LK5 solder link settings to Position B (see
Table 2). When bench top power is used, use of the wall adapter
and the on-board power supplies are no longer required.
Table 2. Solder Links—Settings for Bench Top Power Supply1
Link
SL1
SL2
SL3
SL4
LK3
LK4
LK5
1
The evaluation board can be powered from a wall adapter or
from a bench top power supply. By default, the board is set up
to operate from a 9 V wall adapter using the on-board power
supplies described in Table 1.
Table 1. Power Supplies Provided on the Board
Function
SDP power
Positive rail
Negative rail
ADC VDD rail
VDRIVE (digital power)
Function
+VS
−VS
−VS
+VS
V_SDP
VREF
VDD for ADC
All other solder link settings are as described in Table 3.
POWER SUPPLIES
Power Supply (V)
+5
+7.5
−2.5
+2.5
+3.3
Setting
B
B
B
B
B
B
B
Components Used
ADP2301
ADP7104
ADP2301
ADP7104
ADP7104
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VIN = 9V
WALL ADAPTER
(OPTIONAL)
–VS
POWER SUPPLY CIRCUITRY
ADP7104, ADP2301
GND
+VS
+7.5V/–2.5V
+7.5V
2.5V
3.3V +5V
(OPTIONAL)
+5V
ADR435
VDD
GND
VCM
VSDP
5V
AD8031
ADSP-BF527
DSP
+7.5V
ADA4841-1
VIN1+
VDD1 REF1 VIO1
SDI1
IN1+
SCK1
ADC1
SDO1
IN1–
GND
CNV1
–2.5V
ADA4841-1
+7.5V
VIN1–
GLUE
LOGIC
A B
–2.5V
2.5V
5V
SPORT
+7.5V
VDD2 REF2 VIO2
SDI2
IN2+
SCK2
ADC2
SDO2
IN2–
GND
CNV2
VIN2+
–2.5V
ADA4841-1
+7.5V
VIN2–
GLUE
LOGIC
A B
–2.5V
AD7902/AD7903 PulSAR EVALUATION BOARD
SDP BOARD
Figure 16. Simplified Evaluation Board Functional Block Diagram
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EVAL-AD7902SDZ User Guide
LINK CONFIGURATION OPTIONS
Care should be taken before applying power and signals to the
evaluation board to ensure that all link positions are as required
by the operating mode. There are two modes in which to operate
the evaluation board. The evaluation board can be operated in
SDP controlled mode to be used with the SDP board, or the
evaluation board can be used in standalone mode.
When operating in SDP controlled mode, ensure that VIO is
3.3 V. Operating with a VIO greater than 3.3 V in SDP controlled
mode may damage the SDP board.
The Setting column of Table 3 shows the default positions in which
the links are set when the evaluation board is packaged. When
the board is shipped, it is assumed that you are going to operate
the evaluation board with the SDP board (SDP controlled mode).
Table 3. Solder Links—Factory Default Settings
Link
SL1
SL2
SL3
SL4
SL5
SL6
LK1
LK2
LK3
LK4
LK5
LK6
LK7
LK8
LK9
LK10
LK11
LK12
Setting
A
A
A
A
B
B
A
A
A
A
A
Not applicable
Not applicable
A
A
A
A
A
Function
+VS
−VS
−VS
+VS
Analog input
Analog input
+VS
−VS
V_SDP
VREF
VDD for ADC
Not applicable
Not applicable
ADC2 input
ADC2 input
U17 input
U17 input
ADC2 input
Comment
Change to B if using bench supplies.
Change to B if using bench supplies.
Change to B if using bench supplies.
Change to B if using bench supplies.
Do not alter.
Do not alter.
Change to B if using bench supplies.
Change to B if using bench supplies.
Change to B if using bench supplies.
Change to B if using bench supplies.
Change to B if using bench supplies.
Do not place
Do not place
Do not alter.
Change to B if using ADC1 input.
Change to B if U17 needs to be bypassed.
Change to B if U17 needs to be bypassed.
Do not alter.
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EVALUATION BOARD CIRCUITRY
ANALOG INPUTS
The analog inputs to the evaluation board are SMA Connectors J6
and J14. These inputs are buffered with dedicated amplifier
circuitry (U12 and U17), as shown in Figure 26 and Figure 27.
The circuit not only allows different configurations, input range
scaling, and filtering but also allows adding a dc component and
using different op amps and supplies. The analog input amplifiers
are set as unity-gain buffers by factory default. The amplifier
positive rail is driven from 7.5 V (from U13—ADP7104). The
negative amplifier rail is driven from –VS (generated by U3—
ADP2301).
The default configuration sets all op amps (U12 and U17) at
midscale, generated from a buffered reference voltage divider
(VCM).
The evaluation board is configured by factory default for providing
a pseudo differential analog input path to ADC1 and ADC2 (see
Figure 16).
For dynamic performance, an FFT test can be done by applying
a very low distortion ac source.
balanced with a floating ground. The J10 and J15 connectors are
provided for balanced termination of a signal source. Different
sources can be used; however, most are single-ended sources
that use a fixed output resistance.
By default, the evaluation board uses the amplifiers as unity-gain
buffers. The noninverting input has a common-mode adjustment
that involves a 100 kΩ shunt resistor. This resistor creates a
voltage divider with the source, which must be accounted for
when using the board.
REFERENCE
An external 5 V reference (U6—ADR435) is used to supply the
ADCs directly.
SERIAL INTERFACE
The evaluation board uses the SPORT interface from the
ADSP-BF527 DSP.
Multiple AND gates (U9, U10, and U11) are used to clock and
gate the SPORT transfer to the ADC device.
For low frequency testing, the audio precision source can be
used directly because its outputs are isolated. Set the outputs as
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MODES OF OPERATION
SDP CONTROLLED MODE
STANDALONE MODE
The AD7902 uses a high speed serial interface that allows sampling
rates of up to 1 MSPS. For more information about the operation of
the serial interface, refer to the AD7902 data sheet.
The EVAL-AD7902SDZ can also be used without the EVAL-SDPCB1Z controller board. In this case, the EVAL-AD7902SDZ is
connected to the serial interface using the J5 connector or the
test points. For more information about the operation of the
serial interface, refer to the AD7902 data sheet.
The AD7902 uses the serial interface to transfer data to the
EVAL-SDP-CB1Z.
The EVAL-AD7902SDZ communicates with the EVAL-SDPCB1Z board using level shifters. The EVAL-SDP-CB1Z operates
at a 3.3 V logic level, which allows logic voltages that exceed
3.3 V to be used without damaging the SDP interface.
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HOW TO USE THE SOFTWARE
3.
SETTING UP THE SYSTEM FOR DATA CAPTURE:
BOARD OPERATION/CONNECTION SEQUENCE
After finding the evaluation board, the software connects
to the board and displays the dialog box shown in Figure 18.
1.
2.
3.
4.
5.
Connect the SDP controller board to the evaluation board
via the J5 connector (screw into place as required). The
software is configured to find the evaluation board on either
the J4 or J5 connector of the SDP board.
Power the board with the appropriate supply, as described
in the Power Supplies section.
Connect the EVAL-SDP-CB1Z board to a PC using the
USB cable.
Start the evaluation software. Click Start > All Programs >
AD7902_03_Evaluation > AD7902_03_Evaluation_
Software.
Apply a signal source and capture data.
STARTING THE SOFTWARE
When the software starts running, it searches for hardware
connected to the PC. The software automatically detects the
generic attached to the PC, or you can choose to run the software
in standalone mode without any hardware connected.
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With the evaluation software installed, the following board
operation/connection sequence can be used:
Figure 18. Software Connects to SDP Board
4.
After the board is correctly detected, the main window of
the software appears (see Figure 21), showing that the
EVAL-AD7902SDZ board is connected.
Without Hardware Connected
The software can run in standalone mode when no evaluation
board hardware is connected to the USB port.
1.
Click Start > All Programs > AD7902_03_Evaluation >
AD7902_03_Evaluation_Software.
2.
The software automatically seeks to find the hardware
connected; therefore, when no hardware is connected, a
connectivity error is displayed (see Figure 19). If you wish to
continue without hardware in standalone mode, click Cancel.
With Hardware Connected
To run the program with hardware connected,
1.
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2.
Click Start > All Programs > AD7902_03_Evaluation >
AD7902_03_Evaluation_Software. (To uninstall the
program, click Start > Control Panel > Add or Remove
Programs > AD7902_03_Evaluation.)
If the SDP board is not connected to the USB port when
the software is launched, a connectivity error displays (see
Figure 17). If a connectivity error is displayed, connect the
evaluation board to the USB port of the PC, wait a few
seconds, click Rescan, and follow the instructions.
Figure 19. No Hardware Connected Pop-Up Window Error
The software alerts the user that no hardware is connected
and that the software is going to continue in standalone mode.
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3.
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Figure 17. SDP Board Not Connected to the USB Port Pop-Up Window Error
Figure 20. Software Indicates Operating in Standalone Mode
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You can then load example files or previously saved files and
analyze data. The main window of the software appears (see
Figure 21), showing the evaluation board connected as the
part number from the saved data file.
5.
If you decide to connect hardware at this point, you must
close the software and relaunch it to allow it to search for
the board again.
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4.
EVAL-AD7902SDZ User Guide
Figure 21. Main Window
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OVERVIEW OF THE MAIN WINDOW
The main window of the software is shown in Figure 21 and has
the features described in this section.
File Menu
The File menu offers the choice to
•
•
•
•
•
Load data: load previously captured data.
Save Data as .tsv: save captured data in .tsv format for
future analysis.
Save Picture: save the current screen capture.
Print: print the main window to the default printer.
Exit: close the application.
sample frequency must be an integer divider of the SCLK
frequency. If an unusable sample frequency is input, the software
automatically adjusts the sample frequency accordingly. Units
can be entered as, for example, 10k for 10,000 Hz. The software
automatically adjusts the sample frequency according to the ability
of the ADC connected to the board. For example, if you enter a
value that is beyond the ability of the device, the software indicates
this and reverts to the maximum sample frequency.
Select Channels Checkboxes
Select either Channel 1 or Channel 2 or both to read the data
from a single ADC or both ADCs simultaneously.
Tabs Area
Eval Board Connected Box
The Eval Board Connected box displays the evaluation board connected to the USB port—either EVAL-AD7902 or EVAL-AD7903.
When an evaluation board is not connected to the USB port, the
software can be operated in standalone mode for data analysis,
and the part information notes the part number from the saved
data file.
ADC Settings Area
The ADC Settings area allows changing the sampling frequency
and the reference voltage value, as well as selecting Channel 1 or
Channel 2.
Reference Voltage (V) Box
By default, the external reference voltage is 5 V (ADR435 on-board
reference). The minimum/maximum voltage calculations are based
on this reference voltage. If you change the reference voltage, you
must change this input accordingly.
Sampling Freq (Hz) Box
The default sampling frequency (10000000 Hz) in the Sampling
Freq (Hz) box matches the maximum sample rate of the ADC
connected to the board. Although you can adjust the sampling
frequency, there are limitations in terms of the sample frequencies
that can be entered related to the SCLK frequency applied. The
There are five tabs available in the tabs area of the main window:
Configure, Waveform, Histogram, FFT, and Summary. These
tabs display the data in different formats. Navigation tools are
provided within each tab to allow you to control the cursor,
zooming, and panning (see Figure 22) within the graphs displayed.
Each tab is described in more detail in the Generating a
Waveform Analysis Report; Generating a Histogram of the
ADC Code Distribution; Generating a Fast Fourier Transform
of AC Characteristics; and Generating a Summary of the
Waveform, Histogram, and Fast Fourier Transform sections.
Single Capture Button
Clicking Single Capture performs a single capture from the ADC.
Continuous Capture Button
Clicking Continuous Capture performs a continuous capture
from the ADC.
Num Samples Box
The Num Samples box allows you to select the number of
samples to analyze.
Exit Button
Clicking the Exit button (in the upper right corner of the
window) closes the software. Alternatively, you can select Exit
from the File menu.
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GENERATING A WAVEFORM ANALYSIS REPORT
Figure 22 illustrates the Waveform tab for a 10 kHz sine wave
input signal when the on-board 5 V external reference is used.
The Waveform Analysis area (located toward the bottom of the
window) reports the amplitudes recorded from the captured signal
and the frequency of the signal tone. Select the Channel 1 tab
or Channel 2 tab in the Waveform Analysis area to view the
corresponding waveform.
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CONTROL CONTROL CONTROL
CURSOR ZOOMING PANNING
Figure 22. Waveform Tab
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GENERATING A HISTOGRAM OF THE ADC CODE
DISTRIBUTION
The Histogram tab can be used to perform ac testing or, more
commonly, dc testing. This tab shows the ADC code distribution of
the input and computes the mean and standard deviation, which are
displayed as DC Offset/Mean and Transition Noise, respectively,
in the Histogram Analysis area (located toward the bottom of
the window).
DC Input
A histogram test of dc input can be performed with or without
an external source because the evaluation board has a buffered
VREF/2 source at the ADC input.
To perform a histogram test of dc input,
1.
Figure 23 shows the histogram with ac input for a 1 kHz sine
wave applied to the ADC input and the resulting calculations.
2.
3.
AC Input
To perform a histogram test of ac input,
1.
2.
3.
Apply a sinusoidal signal with low distortion (better than
100 dB) to the evaluation board at the J6 or J14 input SMA
connector pair.
Click the Histogram tab from the main window.
Click Single Capture or Continuous Capture.
If an external source is being used, apply a sinusoidal signal
with low distortion (better than 100 dB) to the evaluation
board at the J6 or J14 input SMA connector pair. It may be
required to filter the signal to ensure that the dc source is
noise-compatible with the ADC.
Click the Histogram tab from the main window.
Click Single Capture or Continuous Capture.
Raw data is then captured and passed to the PC for statistical
computations, and various measured values are displayed in the
Histogram Analysis area.
11798-023
Raw data is then captured and passed to the PC for statistical
computations, and various measured values are displayed in the
Histogram Analysis area.
Figure 23. Histogram Tab
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EVAL-AD7902SDZ User Guide
GENERATING A FAST FOURIER TRANSFORM
OF AC CHARACTERISTICS
Figure 24 shows the FFT tab. This feature tests the traditional
ac characteristics of the converter and displays a fast Fourier
transform (FFT) of the results.
To perform an ac FFT test,
2.
3.
Apply a sinusoidal signal with low distortion (better than
100 dB) to the evaluation board at the J6 or J14 input SMA
connector pair. To attain the requisite low distortion,
which is necessary to allow true evaluation of the part, one
option is to
a. Filter the input signal from the ac source. A band-pass
filter can be used; its center frequency must match the
test frequency of interest.
b. If a low frequency band-pass filter is used when the fullscale input range is more than a few volts peak-to-peak,
use the on-board amplifiers to amplify the signal, thus
preventing the filter from distorting the input signal.
Click the FFT tab from the main window.
Click Sample.
1
The FFT Analysis area displays the results of the captured data.
•
•
•
2
The area labeled 1 in Figure 24 shows the spectrum
information.
The area labeled 2 in Figure 24 displays the fundamental
frequency and amplitude. You can also click Show
Harmonic Content to view information about the second
to fifth harmonics.
The area labeled 3 in Figure 24 displays the performance data,
including the SNR, THD, SINAD, and noise performance.
3
11798-024
1.
As in the histogram test, raw data is then captured and passed
to the PC, which performs the FFT and displays the resulting
SNR, SINAD, THD, and SFDR.
Figure 24. FFT Tab
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EVAL-AD7902SDZ User Guide
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GENERATING A SUMMARY OF THE WAVEFORM,
HISTOGRAM, AND FAST FOURIER TRANSFORM
11798-025
Figure 25 shows the Summary tab. The Summary tab captures
all the display information and provides it in one panel with a
synopsis of the information, including key performance parameters,
such as SNR and THD.
Figure 25. Summary Tab
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EVAL-AD7902SDZ User Guide
EVALUATION BOARD SCHEMATICS AND ARTWORK
11798-026
EVAL-AD7902SDZ SCHEMATICS
Figure 26. Schematic, Page 1
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EVAL-AD7902SDZ User Guide
Figure 27. Schematic, Page 2
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EVAL-AD7902SDZ User Guide
11798-028
Figure 28. Schematic, Page 3
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EVAL-AD7902SDZ User Guide
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11798-029
Figure 29. Schematic, Page 4
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EVAL-AD7902SDZ User Guide
11798-030
Figure 30. Schematic, Page 5
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EVAL-AD7902SDZ User Guide
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11798-031
Figure 31. Schematic, Page 6
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EVAL-AD7902SDZ User Guide
EVAL-AD7902SDZ LAYOUT
Layout Considerations
When laying out the printed circuit board (PCB) for the AD7902,
follow the recommended guidelines described in this section to
obtain the maximum performance from the converter. Figure 33
through Figure 36 show the recommended layout for the AD7902
evaluation board.
Decouple all the power supply pins (VDD1, VDD2, and
VIO) and the REF pin with low ESR and low ESL ceramic
•
11798-032
•
•
capacitors, typically 10 µF and 100 nF, placed close to the
DUT (U1) and connected using short, wide traces to provide
low impedance paths and to reduce the effect of glitches on
the power supply lines.
Separate analog and digital sections and keep power supply
circuitry away from the AD7902.
Avoid running digital lines under the device and crossover
of digital and analog signals because these couple noise into
the AD7902.
Figure 32. EVAL-AD7902SDZ Evaluation Board Silkscreen—Top Assembly
Rev. 0 | Page 26 of 32
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11798-033
EVAL-AD7902SDZ User Guide
11798-034
Figure 33. EVAL-AD7902SDZ Evaluation Board—Top Layer
Figure 34. EVAL-AD7902SDZ Evaluation Board Layer 2—Ground
Rev. 0 | Page 27 of 32
EVAL-AD7902SDZ User Guide
11798-035
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11798-036
Figure 35. EVAL-AD7902SDZ Evaluation Board Layer 3—Power
Figure 36. EVAL-AD7902SDZ Evaluation Board Bottom Layer
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EVAL-AD7902SDZ User Guide
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BILL OF MATERIALS
Table 4. EVAL-AD7902SDZ Bill of Materials
Reference Designator
U1
U2
U3
U4
U5
U6
U7
Part Description
Dual pseudo differential 16-bit, 1 MSPS
PulSAR ADC
1.2 A, 20 V, 1.4 MHz nonsynchronous stepdown switching regulator
1.2 A, 20 V, 1.4 MHz nonsynchronous stepdown switching regulator
Linear regulator, 3.3 V, 20 V, 500 mA,
ultralow noise, CMOS
2.7 V, 800 µA, 80 MHz rail-to-rail I/O single
amplifier SOT23-5
Ultralow noise XFET voltage references
Manufacturer
Analog Devices
Part Number
AD7902
Stock Code
AD7902
Analog Devices
ADP2301AUJZ
ADP2301AUJZ-R7
Analog Devices
ADP2301AUJZ
ADP2301AUJZ-R7
Analog Devices
ADP7104ARDZ-3.3
ADP7104ARDZ-3.3-R7
Analog Devices
AD8031ARTZ
AD8031ARTZ-R2
Analog Devices
ADR435BRZ
ADR435BRZ
Analog Devices
ADP7104ARDZ-2.5
ADP7104ARDZ-2.5-R7
U8
Linear regulator, 2.5 V, 20 V, 500 mA, ultralow
noise, CMOS
Single INV
Fairchild
NC7SZ04M5
Farnell 1013809
U9
Single AND gate
Fairchild
NC7SZ085M5
Farnell 1013807
U10
Single AND gate
Fairchild
NC7SZ085M5
Farnell 1013807
U11
Single AND gate
Fairchild
NC7SZ085M5
Farnell 1013807
U12
Analog Devices
ADA4841-1YRZ
ADA4841-1YRZ-R7
U13
Low noise, high speed amplifier for 16-bit
systems
20 V, 500 mA, low noise, CMOS adjustable LDO
Analog Devices
ADP7104ARDZ
ADP7104ARDZ-R7
U14
Not applicable
Not applicable
Not applicable
Do not place
U15
32k I2C serial EEPROM, 8-lead MSOP
Microchip
24LC32A-I/MS
Farnell 1331330
U16
Not applicable
Not applicable
Not applicable
Do not place
U17
Low noise, high speed amplifier for 16-bit
systems
Capacitor tantalum, 20 V
Analog Devices
ADA4841-1YRZ
ADA4841-1YRZ-R7
AVX
TAJB106K020RNJ
Farnell 197427
Capacitor ceramic, 4.7 µF, 16 V, X7R, 0805
Taiyo Yuden
EMK212B7475KG-T
Farnell 1853520
C8, C20, C23, C25, C27,
C28, C30, C31, C34,
C37, C41, C42, C44,
C53, C54, C56, C57,
C59, C77, C78
C9
Capacitor ceramic, 50 V, X7R
Murata
GRM188R71H104KA93D
Farnell 8820023
Capacitor ceramic, 50 V, X7R, 0805
Murata
C0805C104K5RACTU
Farnell 1414664
C12, C40, C79
Capacitor ceramic, 22 µF, 10 V, X7R, 1206
AVX
LMK316AB7226ML-TR
Farnell 1894515
C14
Capacitor ceramic, 4.7 µF, 16 V, X5R, 1206
Taiyo Yuden
EMK316BJ475KL-T
Farnell 6578937
C15, C16, C17, C21,
C22, C26
C18
Capacitor, 0805, 1 µF, 50 V, X7R
Murata
GRM21BR71H105KA12L
Farnell 1735541
Capacitor ceramic, 50 V, X7R
Murata
GRM188R71H103KA01D
Farnell 1118178
C33, C58
Capacitor ceramic ,10 pF, 100 V, C0G, 0603
AVX
06031A100JAT2A
Farnell 1273324
C35, C74
Capacitor ceramic, 2700 pF, 50 V, C0G/NP0,
0603
TDK
C1608C0G1H272J
Farnell 1844178
C1, C2, C5, C9, C11,
C13, C19
C3, C4, C6, C7
Rev. 0 | Page 29 of 32
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EVAL-AD7902SDZ User Guide
Reference Designator
C24, C29, C32, C36,
C38, C39, C43, C45,
C46, C47, C48, C49,
C50, C51, C52, C55,
C60, C61, C62, C63,
C65, C66, C67, C68,
C69, C70, C71, C72,
C73, C75, C76, C80,
C81
R1
Part Description
Not applicable
Manufacturer
Not applicable
Part Number
Not applicable
Stock Code
Do not place
Resistor, thick film, 2.4 kΩ, 0603, 100 mW, 1%
Yageo
RC0603FR-072K4L
Farnell 1799329
R2
SMD resistor
Multicomp
MC 0.1W 0805 1% 62K
Farnell 9333436
R3
Resistor, 0603, 35.7 kΩ
Multicomp
Farnell 1170942
R4
SMD resistor
Multicomp
R5
SMD resistor
Multicomp
R6
Resistor, 0603, 16.9 kΩ
Multicomp
R7
Resistor, 0805, 12.1 kΩ, 1%
Vishay Draloric
MC 0.063W 0603 1%
35K7
MC 0.0625W 0402 1%
53K6
MC 0.0625W 0402 1%
10K2
MC 0.063W 0603 1%
16K9
CRCW080512K1FKEA
R10
Resistor, 0603, 82 kΩ, 0.063 W, 1%
Multicomp
R11, R13, R42, R44
SMD resistor
Multicomp
R12, R15
Resistor, 20 kΩ, 0.063 W, 1%, 0603
R14, R20, R21, R23,
R25, R26, R36, R45,
R48, R53, R63, R69,
R70, R71, R72
R17, R22, R46, R47
Farnell 1803723
Farnell 1803137
Farnell 1170908
Farnell 1469866
Multicomp
MC 0.063W 0603 1%
82K
MC 0.063W 0603 1%
100K
MC 0063W 0603 1 20K
Farnell 9330771
SMD resistor
Multicomp
MC 0.063W 0603 0R
Farnell 9331662
Resistor, 0805, 49.9 Ω, 0.1%, 0.125 W
Panasonic
ERA6AEB49R9V
Farnell 1810805
R28, R35, R50, R74
Resistor, 2 kΩ, 0.1 W, 1%, 0805
Multicomp
MC 01W 0805 1 2K
Farnell 9332766
R27, R34, R49, R73
Resistor, 100 kΩ, 0.1 W, 1%, 0805
Multicomp
MC 01W 0805 1 100K
Farnell 9332405
R24, R67
Resistor, 22 Ω, 1% 0805
Vishay Draloric
CRCW080522ROFKEAHP
Farnell 1738936
R8, R9, R16, R18, R19,
R29, R30, R31, R32, R33,
R37, R38, R39, R40,
R41, R44, R54, R55,
R56, R59, R60, R61,
R62, R64, R65, R66,
R68
Not applicable
Not applicable
Not applicable
Do not place
Rev. 0 | Page 30 of 32
Farnell 9331573
Farnell 9330402
EVAL-AD7902SDZ User Guide
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RELATED LINKS
Resource
AD7902
ADA4841-1
AD8031
ADP7104
ADP2301
ADR435
Description
Product Page: Dual Pseudo Differential 16-Bit, 1 MSPS PulSAR ADC
Product Page: Unity Gain Stable, Low Noise and Distortion, Rail-to-Rail Output Amplifier
Product Page: 2.7 V, 800 μA, 80 MHz Rail-to-Rail I/O Amplifiers
Product Page : 20 V, 300 mA/500 mA, Low Noise, CMOS LDO
Product Page: 1.2 A, 20 V, 1.4 MHz, Nonsynchronous Step-Down Regulator
Product Page: Ultralow Noise, High Accuracy Voltage References
Rev. 0 | Page 31 of 32
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EVAL-AD7902SDZ User Guide
NOTES
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. Therefore, proper ESD precautions should be taken to avoid performance degradation or loss of functionality.
Legal Terms and Conditions
By using the evaluation board discussed herein (together with any tools, components documentation or support materials, the “Evaluation Board”), you are agreeing to be bound by the terms and conditions
set forth below (“Agreement”) unless you have purchased the Evaluation Board, in which case the Analog Devices Standard Terms and Conditions of Sale shall govern. Do not use the Evaluation Board until you
have read and agreed to the Agreement. Your use of the Evaluation Board shall signify your acceptance of the Agreement. This Agreement is made by and between you (“Customer”) and Analog Devices, Inc.
(“ADI”), with its principal place of business at One Technology Way, Norwood, MA 02062, USA. Subject to the terms and conditions of the Agreement, ADI hereby grants to Customer a free, limited, personal,
temporary, non-exclusive, non-sublicensable, non-transferable license to use the Evaluation Board FOR EVALUATION PURPOSES ONLY. Customer understands and agrees that the Evaluation Board is provided
for the sole and exclusive purpose referenced above, and agrees not to use the Evaluation Board for any other purpose. Furthermore, the license granted is expressly made subject to the following additional
limitations: Customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the Evaluation Board; and (ii) permit any Third Party to access the Evaluation Board. As used herein, the term
“Third Party” includes any entity other than ADI, Customer, their employees, affiliates and in-house consultants. The Evaluation Board is NOT sold to Customer; all rights not expressly granted herein, including
ownership of the Evaluation Board, are reserved by ADI. CONFIDENTIALITY. This Agreement and the Evaluation Board shall all be considered the confidential and proprietary information of ADI. Customer may
not disclose or transfer any portion of the Evaluation Board to any other party for any reason. Upon discontinuation of use of the Evaluation Board or termination of this Agreement, Customer agrees to
promptly return the Evaluation Board to ADI. ADDITIONAL RESTRICTIONS. Customer may not disassemble, decompile or reverse engineer chips on the Evaluation Board. Customer shall inform ADI of any
occurred damages or any modifications or alterations it makes to the Evaluation Board, including but not limited to soldering or any other activity that affects the material content of the Evaluation Board.
Modifications to the Evaluation Board must comply with applicable law, including but not limited to the RoHS Directive. TERMINATION. ADI may terminate this Agreement at any time upon giving written notice
to Customer. Customer agrees to return to ADI the Evaluation Board at that time. LIMITATION OF LIABILITY. THE EVALUATION BOARD PROVIDED HEREUNDER IS PROVIDED “AS IS” AND ADI MAKES NO
WARRANTIES OR REPRESENTATIONS OF ANY KIND WITH RESPECT TO IT. ADI SPECIFICALLY DISCLAIMS ANY REPRESENTATIONS, ENDORSEMENTS, GUARANTEES, OR WARRANTIES, EXPRESS OR IMPLIED, RELATED
TO THE EVALUATION BOARD INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR PURPOSE OR NONINFRINGEMENT OF INTELLECTUAL
PROPERTY RIGHTS. IN NO EVENT WILL ADI AND ITS LICENSORS BE LIABLE FOR ANY INCIDENTAL, SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES RESULTING FROM CUSTOMER’S POSSESSION OR USE OF
THE EVALUATION BOARD, INCLUDING BUT NOT LIMITED TO LOST PROFITS, DELAY COSTS, LABOR COSTS OR LOSS OF GOODWILL. ADI’S TOTAL LIABILITY FROM ANY AND ALL CAUSES SHALL BE LIMITED TO THE
AMOUNT OF ONE HUNDRED US DOLLARS ($100.00). EXPORT. Customer agrees that it will not directly or indirectly export the Evaluation Board to another country, and that it will comply with all applicable
United States federal laws and regulations relating to exports. GOVERNING LAW. This Agreement shall be governed by and construed in accordance with the substantive laws of the Commonwealth of
Massachusetts (excluding conflict of law rules). Any legal action regarding this Agreement will be heard in the state or federal courts having jurisdiction in Suffolk County, Massachusetts, and Customer hereby
submits to the personal jurisdiction and venue of such courts. The United Nations Convention on Contracts for the International Sale of Goods shall not apply to this Agreement and is expressly disclaimed.
©2014 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
UG11798-0-2/14(0)
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