Texas Instruments DAC5687 EVM User manual

DAC5687 EVM
User's Guide
March 2007 Wireless Infrastructure Products
SLWU017B

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Contents
1 Overview .................................................................................................................... 51.1 Purpose............................................................................................................ 51.2 EVM Basic Functions ............................................................................................ 51.3 Power Requirements ............................................................................................ 51.4 Software Installation ............................................................................................. 61.5 Hardware Configuration ......................................................................................... 62 DAC5687 EVM Operational Procedure ........................................................................... 72.1 Starting the Serial Interface Program ........................................................................ 102.2 DAC5687 Initial Setup Tests .................................................................................. 112.3 DAC5687 GUI Register Descriptions ........................................................................ 133 Physical Description .................................................................................................. 163.1 PCB Layout ...................................................................................................... 173.2 Parts List ......................................................................................................... 204 Circuit Description ..................................................................................................... 224.1 Input Clocks ..................................................................................................... 224.2 Input Data ........................................................................................................ 224.3 Output Data ..................................................................................................... 234.4 Control Inputs ................................................................................................... 244.5 Internal Reference Operation ................................................................................. 254.6 External Reference Operation ................................................................................ 255 Revision History ........................................................................................................ 266 Schematics ............................................................................................................... 26
Important Notices ............................................................................................................... 27
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List of Figures
1 Serial Interface GUI ........................................................................................................ 102 DAC5687 Setup for X4L Mode and NCO Tone at F
DAC
/25 ........................................................... 113 Spectrum with CLK2 = 500 MHz, X4L Interpolation and NCO Frequency = 343597383 ......................... 124 DAC5687 Setup for X4 Mode and NCO Tone at F
DAC
/15 ............................................................ 135 Top Layer 1 ................................................................................................................. 176 Layer 2, Ground Plane .................................................................................................... 187 Layer 3, Power Plane ...................................................................................................... 198 Bottom Layer ................................................................................................................ 20
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1 Overview
1.1 Purpose
1.2 EVM Basic Functions
1.3 Power Requirements
1.3.1 Voltage Limits
User's GuideSLWU017B – APRIL 2005 – Revised March 2007
DAC5687 EVM
This user's guide document gives a general overview of the DAC5687 evaluation module (EVM) andprovides a general description of the features and functions to be considered while using this module.
The DAC5687 EVM provides a platform for evaluating the DAC5687 digital-to-analog converter (DAC)under various signal, reference, and supply conditions. This document should be used in combination withthe EVM schematic diagram supplied.
Digital inputs to the DAC can be provided with CMOS level signals up to 250 MSPS (external clock mode)through two 34-pin headers. This enables the user to provide high-speed digital data to the DAC5687device.
The analog outputs from the DAC are available via SMA connectors. Because of its flexible design theanalog outputs of the DAC5687 device can be configured to drive a 50- Ωterminated cable using a 4:1 or1:1 impedance ratio transformer, or single-ended referred to AVDD. The EVM also allows for an option todouble the output power by summing the DAC A and DAC B outputs through a 1:1 transformer.
The EVM allows the user to input single-ended, TTL/CMOS level signals, to generate differential clocksources for both CLK1 and CLK2. See Section 4.1, Input Clocks, for proper configuration and operation.
Power connections to the EVM are via banana jack sockets.
In addition to the internal bandgap reference provided by the DAC5687 device, options on the EVM allowan external reference to be provided to the DAC.
The DAC5687 EVM allows the user to program the DAC5687 internal registers with the supplied computerparallel port cable and serial interface software. The interface allows read and write access to all registersthat define the operation mode of the DAC5687 device.
The demonstration board requires only two power supplies. 3.3 Vdc is required at banana jack J7, with thereturn connected to J9. 1.8 Vdc is required at banana jack J8, with the return to J10.
CAUTION
Exceeding the maximum input voltages can damage EVM components.Undervoltage may cause improper operation of some or all of the EVMcomponents.
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1.4 Software Installation
1.5 Hardware Configuration
Overview
All necessary software to operate the serial interface is provided on the enclosed CD-ROM.1. Insert the CD-ROM into the computer to be used to operate the serial interface.2. Click on the zipped directory called DAC5687SPI_Installv2p2.zip. Extract all of the files into a newdirectory, called C:\temp, on the PC.3. Go the following directory: C:\temp\Installer. Double click on the file called setup.exe.4. The software will create a top level directory at the following location: C:\ProgramFiles\TI.fdr\DAC5687_SPI. This directory will contain the required files as well as a labwindows-cviruntime engine to run the software.5. Once the installation is complete, the software is launched by running DAC5687_SPI.exe. SeeChapter 2, DAC5687 EVM Operational Procedure, for instructions on operating the serial interfacesoftware.
The DAC5687 EVM can be set up in a variety of configurations to accommodate a specific mode ofoperation. Before starting evaluation, the user should decide on the configuration and make theappropriate connections or changes. The demonstration board comes with the following factory-setconfiguration:
•Differential clock mode using transformers T3 and T4. Input single-ended clocks are required at J3 andJ4.•Transformer-coupled outputs using 4:1 transformers T1 and T2.•The converter is set to operate with internal reference. Jumper W1 is installed between pins 2 and 3.•Full-scale output current set to 20 mA through RBIAS resistor R1.•The DAC5687 output is enabled (sleep mode disabled).•TxENABLE is set high to enable the DAC5687 device to process data. A jumper is installed betweenpins 11 and 12 on J15.•Internal PLL disabled. Jumper W3 is installed between pins 2 and 3.•Input data level is set to +3.3VDC. Jumper W2 is installed between pins 1 and 2.
To prepare the DAC5687 EVM for evaluation, connect the following:1. 3.3 V to J7 and the return to J9.2. 1.8 V to J8 and the return to J10.3. Provide a single-ended, 1-V
PP
, 0-V offset sine-wave signal to SMA connector J3 (CLK1) if the internalPLL is to be used. Connect this signal to SMA connector J4 (CLK2) if the PLL is disabled. A secondsine-wave source is required only for dual clock mode. In this mode, the signal on CLK1 is used toclock data into the DAC5687 and the signal on CLK2 is used to clock the internal DAC. CLK1 andCLK2 must be phase-aligned for this option to work properly. In order to preserve the specifiedperformance of the DAC5687 converter, the clock sources must feature very low jitter. Using a clockwith a 50% duty cycle gives optimum dynamic performance.4. Use a digital test pattern generator with 50- Ωoutputs to provide 3.3-V CMOS logic level inputs toconnectors J13 and J14. Adjust the digital inputs to provide the proper voltage levels and setup andhold times at the DAC5687 inputs. See the DAC5687 data sheet (SLWS164 ) for timing information.5. Connect one end of the supplied serial interface cable to the parallel port of a PC. Connect the otherend of the cable to J1 on the EVM.6. The DAC5687 outputs can be monitored using SMA connector J5 for IOUTA and SMA connector J19for IOUTB.
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2 DAC5687 EVM Operational Procedure
DAC5687 EVM Operational Procedure
To prepare the DAC5687 EVM for operation, follow these steps:1. Parallel Port Interface: Connect one end of the supplied serial interface cable to the parallel port of aPC and the other end of the cable to J1 on the EVM and skip steps 2 to 7.2. USB Interface: Connect the provided USB to SPI adapter board to the parallel port connector on theEVM and to a spare USB port on the host PC using the supplied USB cable. The Windows Found NewHardware Wizard should open; if this is not the case make sure the cable is connected properly. Select“No, not this time” from the options available and then click “Next” to proceed with the installation.
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DAC5687 EVM Operational Procedure
3. Select "Install the software automatically (recommended)" as shown below and then click "Next".
4. If Windows is not able to find the appropriate USB drivers press “Back” and select “Install from a list orspecific location (advanced)”. Click “Next”.5. Select "Search for the best driver in these locations" and browse for the folder where the DAC5687program was installed (the default location is C:\Program Files\Texas Instruments\DAC5687). Once thefile path has been selected, click “Next” to proceed.
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DAC5687 EVM Operational Procedure
6. If Windows XP is configured to warn when unsigned (non-WHQL certified) drivers are about to beinstalled, the following screen is displayed unless installing a Microsoft WHQL certified driver. Click on"Continue Anyway" to continue with the installation. If Windows XP is configured to ignore file signaturewarnings, no message will appear.
7. Windows should then display a message indicating that the installation was successful. Click "Finish"to complete the installation.
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2.1 Starting the Serial Interface Program
DAC5687 EVM Operational Procedure
Power up the EVM. After power up, depress switch S1 to reset the DAC5687. Start the software byrunning the following executable:
C:\Program Files\TI.fdr\DAC5687_SPI\ DAC5687_SPI.exe.
If the EVM is powered on with the parallel port connected properly, then the GUI shown in Figure 1 isdisplayed with the default settings read from the device. The hardware and software are now ready fortesting. For serial interface operation, simply click on the switches, up/down arrows, etc.., to select thedesired settings of the DAC5687. If there is a problem with the communication, such as the EVM is notpowered on or the parallel port cable is not connected, an error message will be displayed instructing theuser to correct the problem. Once corrected, hit the "Read All" button, located in the lower right corner ofthe GUI, to read the default settings of the device.
Figure 1. Serial Interface GUI
For normal operation, the user needs only to select values and switches as desired. The values areautomatically sent to the device and read back to verify their configuration.
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