Texas Instruments DAC5686 EVM User manual

DAC5686 EVM
User's Guide
March 2007 Wireless Infrastructure Products
SLWU006E

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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 DAC5686 EVM Operational Procedure ........................................................................... 72.1 Starting the Serial Interface Program ........................................................................ 102.2 DAC5686 EVM Initial Setup Tests ........................................................................... 112.3 DAC5686 GUI Register Descriptions ........................................................................ 133 Physical Description .................................................................................................. 153.1 PCB Layout ...................................................................................................... 153.2 Parts List ......................................................................................................... 194 Circuit Description ..................................................................................................... 214.1 Input Clocks ..................................................................................................... 214.2 Input Data ........................................................................................................ 214.3 Output Data ..................................................................................................... 224.4 Control Inputs ................................................................................................... 234.5 Internal Reference Operation ................................................................................. 244.6 External Reference Operation ................................................................................ 245 Schematic ................................................................................................................ 25
Important Notices ............................................................................................................... 31
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List of Figures
1 Serial Interface GUI ........................................................................................................ 102 DAC5686 Setup for X4 Interpolation, Single Sideband Mode and Tone at Fdac/4 ............................... 113 Spectrum with CLK2 = 500 MHz, X4 Interpolation, Single Sideband Mode, NCO Off ............................ 124 Spectrum with CLK2 = 320 MHz, X4 Interpolation, Single Sideband Mode and NCO Frequency =536870912 .................................................................................................................. 135 Top Layer 1 ................................................................................................................. 166 Layer 2, Ground Plane .................................................................................................... 177 Layer 3, Power Plane ...................................................................................................... 188 Bottom Layer ................................................................................................................ 199 Schematic - Page 1 ........................................................................................................ 2610 Schematic - Page 2 ........................................................................................................ 2711 Schematic - Page 3 ........................................................................................................ 2812 Schematic - Page 4 ........................................................................................................ 2913 Schematic - Page 5 ........................................................................................................ 30
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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 GuideSLWU006E – December 2004 – Revised March 2007
DAC5686 EVM
This user's guide document gives a general overview of the DAC5686 evaluation module (EVM) andprovides a general description of the features and functions to be considered while using this module.
The DAC5686 EVM provides a platform for evaluating the DAC5686 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 160 MSPS through two 34-pinheaders. This enables the user to provide high-speed digital data to the DAC5686 device.
The analog outputs from the DAC are available via SMA connectors. Because of its flexible design theanalog output of the DAC5686 device can be configured to drive a doubly terminated 50- Ωcable using a4:1 or 1:1 impedance ratio transformer, or single-ended referred to AVDD.
The EVM allows for different clock configurations. The user can input a single-ended, differentialECL/PECL or TTL/CMOS level signal, to be used to generate a single-ended or differential clock source.See Section 4.1 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 DAC5686 device, options on the EVM allowan external reference to be provided to the DAC.
The DAC5686 EVM allows the user to program the DAC5686 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 DAC5686 device.
The demonstration board requires a minimum of two power supplies. For non-PLL and 3.3-V I/Ooperation, connect 3.3 Vdc to banana jack J7 with the return connected to J9. Connect 1.8 Vdc to bananajack J8 and the return to J10. Jumper W2 selects the digital I/O voltage level and jumper W3 enables thePLL.
Exceeding the maximum input voltages can damage EVM components. Undervoltage may causeimproper operation of some or all of the EVM components.
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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. Unzip the contents of the DAC5686SPI_Installv1p1.zip into the C:\temp directory on the PC.3. Run the file called setup.exe in the C:\temp\Installer directory.4. The software will install the appropriate files to the C:\Program Files\TI.fdr directory.5. Once the installation is complete, the computer should be rebooted. The software is launched byrunning
C:\ProgramFiles\TI.fdr\DAC5686_SPI\DAC5686_SPI.exe.
A shortcut for that program can be created and placed on the desktop or any other relevant location. SeeSection 2 ,DAC5686 EVM Operational Procedure, for instructions on operating the serial interfacesoftware.
The DAC5686 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 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 DAC5686 output is enabled (sleep mode disabled).•TXENABLE is set high to enable the DAC5686 device to process data.•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 DAC5686 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, 300-mV
PP
, 0-V offset sine-wave signal to SMA connector J3 (CLK1) if theinternal PLL is to be used. Connect this signal to SMA connector J4 (CLK2) if the PLL is disabled. Asecond sine-wave source is required only for dual clock mode. In this mode, the signal on CLK1 isused to clock data into the DAC5686 and the signal on CLK2 is used to clock the internal DAC. CLK1and CLK2 must be phase-aligned for this option to work properly. In order to preserve the specifiedperformance of the DAC5686 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 setup and hold times at theDAC5686 inputs. See the DAC5686 data sheet (SLWS147 ) 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 DAC5686 outputs can be monitored using SMA connector J5 for IOUTA and SMA connector J19for IOUTB.
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2 DAC5686 EVM Operational Procedure
DAC5686 EVM Operational Procedure
This chapter describes the serial interface GUI.
To prepare the DAC5686 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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DAC5686 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 DAC5686program was installed (the default location is C:\Program Files\Texas Instruments\DAC5686). Once thefile path has been selected, click “Next” to proceed.
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DAC5686 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
DAC5686 EVM Operational Procedure
Power up the EVM. After power up, depress switch S1 to reset the DAC5686. Start the software byrunning DAC5686_SPI.exe. If the EVM is powered on with the parallel port connected properly, then theGUI shown in Figure 1 is displayed with the default settings read from the device. If there is a problemwith the communication, such as the EVM is not powered on or the parallel port cable is not connected, anerror message will be displayed instructing the user to correct the problem. Once corrected, hit the ReadAll button to read the default settings of the device.
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.
Figure 1. Serial Interface GUI
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