Texas Instruments ADS1672EVM User manual

User's GuideSBAU147 – March 2009
ADS1672EVM and ADS1672EVM-PDK User's Guide
ADS1672EVM (Left) and ADS1672EVM-PDK (Right)
This user's guide describes the characteristics, operation, and use of the ADS1672EVM, both by itself andas part of the ADS1672EVM-PDK. This evaluation module (EVM) is an evaluation platform for theADS1672 , a high-speed, single-channel, 24-bit, 625kHz delta-sigma analog-to-digital converter (ADC).The EVM allows evaluation of all aspects of the ADS1672 device using a standard serial CMOS interface.A complete circuit description, schematic diagram, and bill of materials are included.
The following related documents are available through the Texas Instruments web site athttp://www.ti.com .
EVM-Compatible Device Data Sheets
Device Literature Number
ADS1672 SBAS402REF5030 SBOS410THS4520 SLOS503REF5025 SBOS410OPA211 SBOS377PCA9535 SCPS129
ADCPro is a trademark of Texas Instruments.Microsoft, Windows are registered trademarks of Microsoft Corporation.All other trademarks are the property of their respective owners.
SBAU147 – March 2009 ADS1672EVM and ADS1672EVM-PDK User's Guide 1Submit Documentation Feedback

1 EVM Overview
2 Introduction
3 Analog Interface
www.ti.com EVM Overview
ADS1672EVM Features:•Contains all support circuitry needed for the ADS1672•Voltage references onboard•Clock options: onboard 20MHz ceramic oscillator or adjustable frequency•GPIO access•Compatible with the TI Modular EVM System
ADS1672EVM-PDK Features:•Easy-to-use evaluation software for Microsoft
®
Windows
®
XP•Data collection to text files•Built-in analysis tools including scope, FFT, and histogram displays•Complete control of board settings•Easily expandable with new analysis plug-in tools from Texas Instruments
As a stand-alone unit, you can use the ADS1672EVM as a prototyping or troubleshooting tool.
For use with a computer, the ADS1672EVM-PDK is available. This kit combines the ADS1672EVM boardwith the DSP-based MMB0 motherboard, and includes ADCPro™ software for evaluation.
You can connect the ADS1672EVM through the MMB0 motherboard and then to a computer via anavailable USB port. This manual shows how to use the MMB0 as part of the ADS1672EVM-PDK, but doesnot provide technical details about the MMB0 itself.
ADCPro is a program for collecting, recording, and analyzing data from ADC evaluation boards. ADCProhas a number of plug-in programs, so it can be expanded easily with new test and data collection plug-ins.You control the ADS1672EVM-PDK with a plug-in that runs in ADCPro. For more information aboutADCPro, see the ADCPro™ Analog-to-Digital Converter Evaluation Software User's Guide (literaturenumber SBAU128 ), available for download from the TI web site.
This manual covers the operation of both the ADS1672EVM and the ADS1672EVM-PDK. It does notdescribe the MMB0 motherboard in detail. Throughout this document, the abbreviation EVM and the termevaluation module are synonymous with the ADS1672EVM.
The ADS1672EVM is an evaluation module built to the TI Modular EVM System specification. You canconnect the ADS1672EVM to any Modular EVM System interface card.
The ADS1672EVM is available as a stand-alone printed circuit board (PCB) or as part of theADS1672EVM-PDK, which includes an MMB0 motherboard and software. As a stand-alone PCB, theADS1672EVM is useful for prototyping designs and firmware development.
Note that the ADS1672EVM cannot run software. To connect it to a computer, some type of interface isrequired.
The ADS1672EVM board applies 5V of power (VCC) to the ADS1672 (U6) and THS4520 (U2). TheTHS4520, a wideband, fully-differential amplifier, drives the differential inputs of the ADS1672. This devicewas selected because of its slew rate (570V/ µs), settling time (7ns to 0.1%), low noise (2nV/ √Hz) and lowharmonic distortion (HD3: –123dBc at 100kHz).
SBAU147 – March 2009 ADS1672EVM and ADS1672EVM-PDK User's Guide 3Submit Documentation Feedback

THS4520 ADS1672
R56
R55 R14
R15
R12
R11
R5 R10
R9 R8
R3
C10
(NI)
C18
C55
C14
(NI)
VCC
VCCRCM
RCM
-IN (J1 or
P3-1)
+IN (J2 or
P3-2)
R47
(NI)
R53
(NI)
R4
(NI)
R48
(NI)
R6 R50
(NI)
R54
(NI)
R13
(NI)
R49
(NI)
C64
(NI)
C65
(NI)
Analog Interface

4 Reference Buffer
OPA211
C52
47 Fm
C15
C19
C71
C26
R17
R33
R18
VREFP
+5VCC
C29 || C54 || C16
REF5030
OUT
TRIM
U1
U4 C24
22 Fm
C73
47 Fm
C23
0.1 Fm
5 Power Supplies
Reference Buffer www.ti.com
The ADS1672 reference pins have switched capacitor inputs. At a clock rate of 20MHz (X1), a chargeinjection in and out of the ADS1672 reference input occurs. The external reference voltage that drives theADS1672 reference pin must settle in less than 50ns. The REF5030 (U1) generates the 3.0V referencesignal (Figure 3 ). The output of the REF5030 is heavily filtered to remove noise. The onboard OPA211(U4) again filters and buffers the reference signal so that the reference signal noise to the ADS1672 isless than the noise generated by the converter itself. The OPA211 is a low-noise, unity-gain stableamplifier that provides a reliable current source for the ADS1672 reference input. The OPA211 and outputdecoupling capacitors work together to settle the VREFP (ADS1672) reference input voltage to within ±1/2LSB, every 50ns. This board uses a 22 µF ceramic capacitor with a 0.1 µF ceramic capacitor directlyacross the reference inputs, VREFP and VREFN. Note that the 22 µF and 0.1 µF capacitors are placed asclose to the ADS1672 reference pins as possible. These capacitors further reduce noise that is commonto both inputs. The ADS1672 VREFN pin goes to ground.
Figure 3. ADS1672 External Reference and Buffer
J4 (see Figure 1 ) is the power-supply input connector. Table 2 lists the configuration details for J4.
Table 2. J4 Configuration: Power-Supply Input
Pin No. Pin Name Function Required
J4.1 +VA +VCC OptionalJ4.2 –VA –VCC OptionalJ4.3 +5VA +5VCC AlwaysJ4.4 NC No connection NoJ4.5 NC No connection NoJ4.6 AGND Analog ground input AlwaysJ4.7 NC No connection NoJ4.8 NC No connection NoJ4.9 +3.3V 3.3V digital supply AlwaysJ4.10 NC No connection No
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6 Digital Interface
www.ti.com Digital Interface
It is easy to interface the ADS1672EVM board to multiple control platforms. The P2 connector (Figure 4 ,Samtec part number SSW-110-22-S-D-VS) provides a convenient digital access to the key ADS1672 I/Opins. Consult Samtec at http://www.samtec.com or call 1-800-SAMTEC-9 for a variety of mating connectoroptions.
SW1, a 10-position DIP switch (Figure 4 ), gives users the ability to change the setting of the ADS1672digital configuration pins when the EVM is used as a stand-alone evaluation board. Pull-up/-down resistorsare provided to set the static state of the digital configuration pins. All position settings for SW1 must beoff (factory default state) when the board
as

6.1 Serial Data Interface, P2
Digital Interface

6.2 Digital Control Signal PIN Configuration, SW1
7 Clock Source
5VCC
EN
W2
Connect When
Using Onboard
20MHz Clock
W3
Internal or
External
Modular Clock
Select
INT
EXT
MCLK
www.ti.com Clock Source
When using the I
2
C function through U5 (with or without ADCPro connected), all SW1 switches should bein the OFF position (see Figure 4 ).
The data clock and data out communications are directed through P2. All remaining ADS1672 digitalcontrol pins are configured with SW1. Table 4 describes the settings of the digital configuration switches.
The shunt on W3 must be moved to cover pin positions 2 and 3 in order to use the external clock appliedto J3. The control signal operating modes in Table 4 are further explained in the ADS1672 data sheet.
Note: All SW1 switches must be configured in the OFF position when using ADCPro software.
Table 4. SW1: Supplemental Analog Interface Pinout
Pin Number Signal Description
Data rate selection, bit 1 (oversamplingSW1.1 DRATE2
ratio select pin)Data rate selection, bit 0 (oversamplingSW1.2 DRATE1
ratio select pin)SW1.3 NC No connection
Digital filter path selection: If FPATH = '0',SW1.4 FPATH then path is wide-bandwidth; if FPATH ='1', then path is low-latencyConfigure low-latency digital filter: IfLL_CONFIG =

5VCC
EN
W2
Disconnect When
Using External Clock
W3
Internal or
External
Modular Clock
Select
INT
EXT
MCLK
8 Use as a Stand-Alone EVM
9 EVM Operation
9.1 Analog Input
9.2 Digital Control
FSX
GPIO
START Shorted for
ADCPro operation
W4
Use as a Stand-Alone EVM www.ti.com
Figure 6. W2 and W3 Jumpers for External Modulator Clock
The ADS1672EVM can be used as a stand-alone EVM, provided that the proper control signals areapplied to serial input connector P2 (top or bottom side). The required power supplies (+5VA and +3.3VD)can be connected directly to J4 pins 3 and 9 or test points TP5 and TP7, respectively. Both supplies arereferenced to J4 pin 6 or TP8, and should be sourced from clean, well-regulated lab supplies for bestperformance. The minimum control lines necessary are the active-low chip select ( CS) and START inputs,which are applied to P2 pins 1 and 7. If an external serial clock is desired, the signal is applied to P2 pin5. The ADS1672 digital configuration pins can be set statically by using SW1, or can be manipulatedthrough U5 by an I
2
C controller connected to P2 pins 16 and 20 (all SW1 positions must be set to offwhen using U5). For additional details, please see section Section 9 of this document and review theADS1672 datasheet.
This section provides information on the analog input, digital control, and general operating conditions ofthe ADS1672EVM.
The differential

9.3 ADS1672EVM-PDK Power Supply
9.4 Default Jumper Settings and Switch Positions
www.ti.com EVM Operation
The ADS1672EVM can be powered with the J4 connector or by attaching the MMB0 board. The MMB0board provides the 5V and 3.3V power to the ADS1672EVM. Because the circuitry is provided on theADS1672EVM, the complete system can be powered from the supplied +6V, 3A ac adapter.
Figure 8 shows the jumpers found on the EVM and the factory default conditions for each.
Figure 8. ADS1672EVM Default Jumper Locations
Table 5 provides a list of switches found on the EVM and the factory default conditions for each.
Table 5. List of Switches
Switch Default Position Switch Description
Selects U2 (THS4520) CM inputW1 Not installed
sourceW2 Short across pins Onboard 20MHz OscillatorConfigures board for ADCProW4 Top two pins shorted
operation
Configures board for ADCProW6 Top two pins shorted
operation
Configures board for ADCProSW1 All 10 switches in OFF position
operationP2 Pins 3 and 5 shorted Connects CLKX TO CLKR
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10 ADS1672EVM-PDK Kit Operation
10.1 Installing the ADCPro Software
ADS1672EVM-PDK Kit Operation www.ti.com
This section provides information on using the ADS1672EVM-PDK, including setup, program installation,and program usage.
CAUTION
Do not connect the ADS1672EVM-PDK before installing the ADCPro softwareon a suitable PC. Failure to observe this caution may cause Windows to notrecognize the ADS1672EVM-PDK as a connected device.
To prepare to evaluate the ADS1672 with the ADS1672EVM-PDK, complete the following steps:Step 1. Install the ADCPro software (if not already installed) on a PC.Step 2. Install the ADS1672EVM-PDK EVM plug-in software.Step 3. Set up the ADS1672EVM-PDK.Step 4. Connect a proper power supply or use the included AC adapter.Step 5. Run the ADCPro software.Step 6. Complete the Microsoft Windows USB driver installation process.
Each task is described in the subsequent sections of this document.
The latest software is available from Texas Instruments' website at http://www.ti.com/ . The CD-ROMshipped with the ADS1672EVM may not contain the latest software, but the ADCPro installer will check forupdates when executed (if connected to the Internet), and then give you the option of downloading andinstalling the latest version. Refer to the http://focus.ti.com/lit/ug/sbau128/sbau128.pdf for instructions oninstalling and using ADCPro.
To install the ADS1672EVM-PDK plug-in, run the file: ads1672evm-pdk-plug-in-1.0.0.exe (1.0.0 is theversion number, and increments with software version releases; you may have a different version on yourCD). Double-click the file to run it; then follow the instructions shown. After installation, you can use theADCPro Update Check feature to check for newer versions of the ADS1672EVM-PDK plug-in.
The software should now be installed, but the USB drivers may not have been loaded by the PC operatingsystem. The USB driver upload step will complete when the ADCPro software is executed (seeSection 11.2 ,Running the Software and Completing the Driver Installation).
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10.2 Setting Up the ADS1672EVM-PDK
www.ti.com ADS1672EVM-PDK Kit Operation
The ADS1672EVM-PDK contains both the ADS1672EVM and the MMB0 motherboard; however, thedevices are shipped unconnected. Follow these steps to set up the ADS1672EVM-PDK:Step 1. Unpack the ADS1672EVM-PDK kit.Step 2. Set the jumpers and switches on the MMB0 as shown in Figure 9 .•Set the Boot Mode switch to USB.•Connect +5V and +5VA on jumper block J13 (if +5V is supplied from J14 +5VA).•Leave +5V and +VA disconnected on jumper block J13.•If the PDK will be powered from an ac adapter, connect J12. If the PDK will be poweredthrough the terminal block, disconnect J12. See Section 9.3 for details on connecting thepower supply.
Figure 9. MMB0 Initial Setup
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ADS1672EVM-PDK Kit Operation www.ti.com
3. Plug the ADS1672EVM into the MMB0 as Figure 10 illustrates.
Figure 10. Connecting ADS1672EVM to MMB0
CAUTION
Do not misalign the pins when plugging the ADS1672EVM into the MMB0.Check the pin alignment carefully before applying power to the PDK.
Step 3. Set the jumpers and switches on the ADS1672EVM as shown in Figure 8 (note that thesesettings are the factory-configured settings for the EVM).
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11 About the MMB0
11.1 Connecting the Power Supply
11.1.1 Connecting an AC Adapter
www.ti.com

11.1.2 Connecting a Laboratory Power Supply
About the MMB0 www.ti.com
A laboratory power supply can be connected through terminal block J14 on the MMB0, as shown inFigure 12 .
To use a unipolar lab power supply configuration:•Disconnect J12 on the MMB0.•Connect a +5V dc supply to the +5VD terminal on J14.•Connect ground of the dc supply to the GND terminal on J14.
It is not necessary to connect a +5V dc supply voltage to the +5VA terminal on J14 if the +5V/+5VAposition on J13 is shorted.
Figure 12. Laboratory Power-Supply Connection
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11.2 Running the Software and Completing the Driver Installation
www.ti.com About the MMB0
Note: The software is continually under development. These instructions and screen images arecurrent at the time of this writing, but may not exactly correspond to future releases.
The program for evaluating the ADS1672EVM-PDK is called ADCPro. This program uses plug-ins tocommunicate with the EVM. The ADS1672EVM-PDK plug-in is included in the ADS1672EVM-PDKpackage.
The program currently runs only on Microsoft Windows platforms of WindowsXP.
Follow these procedures to run ADCPro and complete the necessary driver installation.Step 1. Start the software by selecting ADCPro from the Windows Start menu. The screen inFigure 13 appears.
Figure 13. ADCPro Software Start-up Display Window
SBAU147 – March 2009 ADS1672EVM and ADS1672EVM-PDK User's Guide 17Submit Documentation Feedback

About the MMB0

www.ti.com

About the MMB0 www.ti.com
Figure 17. Found New Driver Wizard, Screen 3
Figure 18. Found New Driver Wizard, Screen 4
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