EVAL-AD7171EBZ

Evaluation Board User Guide UG-081 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 AD7171 16-Bit, Low Power Sigma-Delta ADC down mode in which the device consumes 5 μA, thus increasing the battery life of the product. FEATURES Full featured evaluation board for the AD7171 Standalone USB interface Various linking options PC software for control of the AD7171 Full data on the AD7171 is available in the AD7171 data sheet available from Analog Devices, Inc., and should be consulted in conjunction with this data sheet when using the evaluation board. The evaluation board interfaces to the USB port of an IBM®compatible PC. Software is available with the evaluation board that allows users to easily communicate with the AD7171. GENERAL DESCRIPTION This document describes the evaluation board for the AD7171, which is a very low power, 16-bit sigma-delta (Σ-Δ) ADC. It contains a precision 16-bit sigma-delta (Σ-Δ) ADC and has one differential input. The device has an output data rate of 125 Hz. It also has an on-board clock, eliminating the need for an external clock. Consuming only 135 μA, the AD7171 is particularly suitable for portable or battery operated products where very low power is a requirement. The AD7171 also has a power- Note that the AD7171 evaluation board software should be installed before connecting the AD7171 evaluation board to the PC. Another component on the AD7171 evaluation board is the ADP3330 high precision, low power, 3.3 V output voltage regulator, which is used to power the USB/SPI interface. FUNCTIONAL BLOCK DIAGRAM ANALOG INPUT VOLTAGE REFERENCE AD7171 VOLTAGE REGULATOR SPI/USB INTERFACE REFIN Figure 1. Please see the last page for an important warning and disclaimers. Rev. 0 | Page 1 of 12 PC AND LabVIEW™ BASED SOFTWARE 08751-001 EXTERNAL SUPPLY UG-081 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1  Evaluation Board Software ...............................................................5  General Description ......................................................................... 1  Software Description ....................................................................5  Functional Block Diagram .............................................................. 1  Installating the Software ...............................................................5  Revision History ............................................................................... 2  Using the Software ........................................................................5  Evaluation Board Hardware ............................................................ 3  Main Window ................................................................................6  Power Supplies .............................................................................. 3  Evaluation Board Schematic and Artwork.....................................7  Links ............................................................................................... 3  Ordering Information .......................................................................9  Setup Conditions .......................................................................... 3  Bill of Materials ..............................................................................9  Sockets ........................................................................................... 3  ESD Caution................................................................................ 12  Interfacing to the Evaluation Board ........................................... 4  REVISION HISTORY 2/10—Revision 0: Initial Version Rev. 0 | Page 2 of 12 Evaluation Board User Guide UG-081 EVALUATION BOARD HARDWARE POWER SUPPLIES SETUP CONDITIONS The AD7171 evaluation board is powered via the 5 V supply from the USB connector, J51. This 5 V supply can be used to power the AD7171 directly. A 3.3 V regulated voltage from the on-board ADP3330 (a high precision, low power, 3.3 V output voltage regulator) can also be used. Alternatively, the AD7171 can be powered using an external 3 V or 5 V power supply via J6. Care should be taken before applying power and signals to the evaluation board to ensure that all link positions are set per the required operating mode. Table 2 shows the position in which all the links are initially set. LINKS There are four groups of link options that must be set for the required operating setup before using the evaluation board. The functions of these link options are outlined in Table 1. SOCKETS Three sockets are relevant to the operation of the AD7171 on this evaluation board. The functions of these sockets are outlined in Table 3. Table 1. Evaluation Board Link Settings Link J3, J7 Default IN J8, AGND AVDD, IN J1 3.3 V J2 IN Description These links are used to connect the AIN(+) and AIN(−) inputs to AVDD/2. With this configuration, a noise analysis can be performed. With these links removed, an external voltage can be applied to AIN using J4. AVDD can be used as the reference for the AD7171. With J8 in Position AVDD and Link AGND inserted, AVDD is connected to REFIN(+), and REFIN(−) is connected to AGND. With J8 in Position REF and Link AGND inserted, REFIN(+) is connected to the ADR391, (2.5 V) and REFIN(−) is connected to AGND. To use another reference source, remove the J8 and AGND links. J1 is used to select the power source for AVDD on the AD7171. J1 in Position 3.3 V selects the 3.3 V regulated output from the onboard ADP3330 voltage regulator. J1 in Position 5 V selects the 5 V supply from the USB connector, J51. J1 in Position EXT selects an external power supply, supplied via J6. These links connect the AD7171 serial interface pins to the SPI interface of the microcontroller. The links should be in place to use the AD7171 evaluation board software. With these links removed, the AD7171 can be interfaced to an external microcontroller. Table 2. Initial Link and Switch Positions Link J3, J7 J8, AGND J1 J2 Position IN AVDD, IN 3.3 V IN Function AIN(+) and AIN(−) are shorted to AVDD/2. The reference voltage is set to 3.3 V (AVDD). The 3.3 V supply is used as AVDD for the AD7171. The AD7171 is interfaced to the on-board microcontroller Table 3. Socket Functions Socket J4 J5 J6 Description 2-lead terminal block. An external analog signal can be connected to the analog input pins of the AD7171 using this terminal block. 2-lead terminal block. An external reference source can be connected to the analog input pins of the AD7171 using this terminal block. 2-lead terminal block. An external power supply can be used to supply the AD7171 using this terminal block. Rev. 0 | Page 3 of 12 UG-081 Evaluation Board User Guide 1. INTERFACING TO THE EVALUATION BOARD Interface to the evaluation board is via a standard USB connector, J51, which connects the evaluation board to the USB port of a PC. A standard USB connector cable is included with the AD7171 evaluation board to connect it to the USB port of the PC. Because the board is powered via the USB connector, there is no need for an external power supply, although if preferred, one can be connected via J6. Communication between the AD7171 and the PC is via the USB/SPI interface. The on-board USB controller (U2) handles this communication. 2. 3. Install the AD7171 evaluation board software using the supplied AD7171 evaluation board CD before connecting the board to the PC. After the AD7171 evaluation board software is installed, connect the board to the PC via J1 on the AD7171 evaluation board and via the USB port on the PC using the supplied USB connector cable. The PC automatically finds the new USB device and identifies it as the AD779x Evaluation Board. Follow the on-screen instructions that appear. During the installation process, if the Hardware Installation window appears as shown in Figure 2, click Continue Anyway to complete the installation of the AD7171 evaluation board. 08751-002 To set up the USB/SPI interface, use the following procedure: Figure 2. Hardware Installation Window Rev. 0 | Page 4 of 12 Evaluation Board User Guide UG-081 EVALUATION BOARD SOFTWARE 3. SOFTWARE DESCRIPTION The AD7171 evaluation board is shipped with a CD containing software that can be installed onto a standard PC to control the AD7171. The software communicates with the AD7171 through the USB cable, which accompanies the board. The software allows you to configure the AD7171 and to read conversion data from the AD7171. Data can be read from the AD7171 and displayed or stored for later analysis. For further information, see the AD7171 data sheet available from Analog Devices. 4. At the prompt, select a destination directory, which is C:\Program Files\Analog Devices\AD7171 by default. Once the directory is selected, the installation procedure copies the files into the relevant directories on the hard drive. The installation program creates a program group called Analog Devices with the subgroup AD7171 in the Start menu of the taskbar. Once the installation procedure is complete, double-click the AD7171 icon to start the program. INSTALLATING THE SOFTWARE USING THE SOFTWARE Use the following steps to install the software: Figure 3 shows the main window that is displayed when the program starts. The Main Window section briefly describes the various menu and button options in the main window. Start Windows® and insert the CD. The installation software should launch automatically. If it does not, use Windows Explorer to locate the setup.exe file on the CD. Double-click this file to start the installation procedure. The data that is read can be exported to other packages, such as MathCAD™ or Microsoft® Excel, for further analysis. 08751-003 1. 2. Figure 3. AD7171 Evaluation Software Main Window Rev. 0 | Page 5 of 12 UG-081 Evaluation Board User Guide MAIN WINDOW Reference Menu Bar File The value of the external reference should be displayed in the Reference (V) text box. This allows the user to read previously stored data for display or analysis, write the current set of data to a file for later use, and exit the program. Status Bits About This box displays the contents of the status register. Waveform The gathered conversions are displayed in graph form. This provides revised information about the application. Codes/Volts Buttons Reset The gathered samples can be displayed in codes or in voltage format. When the CODES option is selected, the values are displayed as code. To display the information in volts, select the VOLTS option. This allows the user to reset the AD7171 software. Exit This allows the user to exit the software. It serves the same purpose as Quit in the File pull-down menu. Histogram Sample Waveform Analysis (Volts) This allows the user to read a number of samples from the AD7171. Noise analysis is then performed on the samples. These samples can be stored for further analysis. The sample size is entered in the Num Samples text box. The gathered samples are processed, and the minimum conversion, maximum conversion, average conversion, p-p noise and rms noise are displayed in volts. The gathered samples are used to generate a histogram. Waveform Analysis (Codes) Continuous This allows the user to read a number of samples continuously. The software gathers a number of samples as specified by the Num Samples text box, performs noise analysis on the samples, and gathers the next group of samples. The gathered samples are processed, and the minimum conversion, maximum conversion, average conversion, p-p noise and rms noise are displayed in codes. Rev. 0 | Page 6 of 12 Evaluation Board User Guide UG-081 EVALUATION BOARD SCHEMATIC AND ARTWORK 08751-004 Figure 4. AD7171 Evaluation Board Schematic Rev. 0 | Page 7 of 12 Evaluation Board User Guide 08751-005 UG-081 08751-006 Figure 5. AD7171 Evaluation Board—Solder Side View 08751-007 Figure 6. AD7171 Evaluation Board—Component Side View Figure 7. AD7171 Evaluation Board—Component Layout Diagram Rev. 0 | Page 8 of 12 Evaluation Board User Guide UG-081 ORDERING INFORMATION BILL OF MATERIALS Table 4. Reference Designator Integrated circuits U1 U2 U51 U52 U53 XTAL51 LED5, LED50, LED51 L1 D1 Capacitors C1 to C3 C4, C6 C5 C7, C9, C11, C12, C13, C54 to C61 C8, C10 C51, C52, C53 C62, C63, C64 Resistors R1, R2 R3, R4, R52, R53 R5, R50, R51 R6, R7, R55, R56, R57 R8 R9, R10, R11, R54 Links J3, J7, AGND (2× 1 way) J8 (3× 1 way) J1 (3× 2 way) J2 (5× 3 way) At J1, J2, J3, J7, AGND, J8 Connectors J51 J4, J5, J6 Description Manufacturer Part Number 24 MHz crystal Green LED Ferrite bead Diode Analog Devices Analog Devices Cypress Semiconductor Corporation Microchip Technology, Inc. Analog Devices AEL Crystals Kingbright, Elec. Co., Ltd Tyco Electronics Micro Commercial Components Corp. AD7171BCPZ ADR391AUJZ CY7C68013A-56LFXC 24LC64-I/SN ADP3330ARZ-3.3 X24M000000S244 KP-2012SGC BMB2A0300AN1 DL4001-TP Capacitors 10 nF ceramic 1 μF ceramic 0.1 μF ± 10% ceramic 10 μF tantalum 12 pF ceramic 4.7 μF ceramic Phycomp Phycomp Phycomp AVX Corporation Phycomp Phycomp Not inserted 223858615636 223878615649 223878615649 TAJA106M016R 223886715129 225520613672 0 Ω resistor 1 kΩ resistor 10 kΩ resistor 100 kΩ resistor 1.5 Ω resistor 100 Ω resistor Phycomp Phycomp Phycomp Phycomp Phycomp Phycomp 232270296001 RC0603FR-071KL RC0603FR-0710KL RC0603FR-07100KL RC0603FR-071R5L RC0603FR-07100RL Pin headers Pin headers Pin headers Pin headers Shorting plugs Harwin Plc Harwin Plc Tyco Electronics Tyco Electronics Harwin Plc M20-9990246 M20-9990246 1241050-3 1241050-5 M7566-05 USB Mini-B connector 2-way terminal block Molex Phoenix Contact 565790576 1727010 USB controller 24LC64 Rev. 0 | Page 9 of 12 UG-081 Evaluation Board User Guide NOTES Rev. 0 | Page 10 of 12 Evaluation Board User Guide UG-081 NOTES Rev. 0 | Page 11 of 12 UG-081 Evaluation Board User Guide NOTES ESD CAUTION Evaluation boards are only intended for device evaluation and not for production purposes. Evaluation boards are supplied “as is” and without warranties of any kind, express, implied, or statutory including, but not limited to, any implied warranty of merchantability or fitness for a particular purpose. No license is granted by implication or otherwise under any patents or other intellectual property by application or use of evaluation boards. Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Analog Devices reserves the right to change devices or specifications at any time without notice. Trademarks and registered trademarks are the property of their respective owners. Evaluation boards are not authorized to be used in life support devices or systems. ©2010 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. UG08751-0-2/10(0) Rev. 0 | Page 12 of 12