AD9520-4/PCBZ

Evaluation Board User Guide UG-076 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 AD9520-0, AD9520-1, AD9520-2, AD9520-3, AD9520-4, and AD9520-5 Product Series FEATURES GENERAL DESCRIPTION Simple power connection using 6 V wall adapter and on-board LDO voltage regulators LDOs are easily bypassed for power measurements 5 ac-coupled differential LVPECL SMA connectors 7 LVPECL differential headers for additional outputs SMA connectors for 2 reference inputs Charge pump output Clock distribution input USB connection to PC Microsoft Windows-based evaluation software with simple graphical user interface On-board PLL loop filter Easy access to digital I/O and diagnostic signals via I/O header Status LEDs for diagnostic signals The AD9520 product series from AD9520-0 to AD9520-5 are very low noise phase-locked loop (PLL) clock synthesizers featuring an integrated voltage controlled oscillator (VCO), clock dividers, and up to 24 outputs. The AD9520 product series features automatic holdover and a flexible reference input circuit allowing very smooth reference clock switching. The AD9520 product family also features the necessary provisions for an external VCXO. The AD9520 evaluation board is a compact, easy to use platform for evaluating all features of the AD9520-0 to AD9520-5. This user guide covers all six versions of the AD9520 product family. Although the Quick Start Guide to the AD9520 PLL section applies specifically to the AD9520-4, increasing the N (feedback) divider and channel divider increases the VCO frequency to the allowable frequency range of other AD9520 versions. APPLICATIONS Clocking of analog-to-digital and digital-to-analog converters up to 2.9 GHz Networking and communications line cards Test and measurement equipment Wireless base stations, controllers Clock cleanup/jitter attenuation Clock distribution For the AD9520-5, which lacks the internal VCO, certain portions of this user guide that apply to the internal VCO (such as VCO calibration) can be ignored. This document covers the AD9520 family. The AD9522 family, which is identical to the AD9520 except that it has low voltage differential signaling (LVDS) outputs, is covered in the UG-077. For convenience, detailed information from the AD9520 data sheet has been included here. Use this user guide in conjunction with the AD9520 and AD9522 data sheets and software documentation available from the Analog Devices, Inc. website. 08746-001 AD9520 EVALUATION BOARD Figure 1. PLEASE SEE THE LAST PAGE FOR AN IMPORTANT WARNING AND LEGAL TERMS AND CONDITIONS. Rev. A | Page 1 of 16 UG-076 Evaluation Board User Guide TABLE OF CONTENTS Features .............................................................................................. 1 Register W/R Box ..........................................................................9 Applications ....................................................................................... 1 SYNC, PD (Power Down), and RESET Buttons .......................9 General Description ......................................................................... 1 EEPROM Control Window .........................................................9 AD9520 Evaluation Board............................................................... 1 Reference (R) Divider Window ...................................................9 Revision History ............................................................................... 2 Feedback (N) Divider Window ................................................ 10 Evaluation Board Hardware ............................................................ 3 R and N Delay Window ............................................................. 10 Power and PC Connections ........................................................ 3 Phase Frequency Detector (PFD) Window ............................ 10 Signal Connections ...................................................................... 3 Charge Pump Setup Window ................................................... 11 Bypassing the Wall Power Supply............................................... 3 Zero Delay Window ................................................................... 11 Bypassing the PLL (Clock Distribution Only) ............................. 3 VCO Calibration Window ........................................................ 11 Using an External VCXO ............................................................ 3 Channel Divider Window ......................................................... 11 Using I C Serial Port Mode ......................................................... 3 Output Driver Window ............................................................. 12 Evaluation Board Software .............................................................. 4 Debug Window ........................................................................... 12 Software Installation .................................................................... 4 Evaluation Software Menu Items.................................................. 13 Running the Software .................................................................. 4 Menu Bar ..................................................................................... 13 Quick Start Guide to the AD9520 PLL .......................................... 5 AD9520 PLL Loop Filter ............................................................... 14 Evaluation Software Components .................................................. 7 Main Window ............................................................................... 7 Using the Evaluation Board to Program an AD9520 on a User Board ................................................................................................ 15 PLL Reference Input Window .................................................... 8 AD9520 Binary File Generation ................................................... 16 PLL Configuration Window ....................................................... 8 Checksum Generation ............................................................... 16 REFMON, STATUS, and LD Buttons ........................................ 8 Avoiding Checksum Mismatches ............................................. 16 2 REVISION HISTORY 5/2017—Rev. 0 to Rev. A Changes to Title and General Description Section ...................... 1 Changes to Power and PC Connections Section, Signal Connections Section, Bypassing the Wall Power Supply Section, and Using I2C Serial Port Mode Section........................................ 3 Changes to Software Installation Section and Running the Software Section ............................................................................... 4 Added Table 1 Caption .................................................................... 5 Change to Figure 6 Caption ............................................................ 5 Changes to PLL Reference Input Window Section, PLL Configuration Window Section, and REFMON, STATUS, and LD Buttons Section........................................................................... 8 Changes to SYNC, PD (Power Down), and RESET Buttons Section, and Reference (R) Divider Window Section ................. 9 Changes to Feedback (N) Divider Window Section and R and N Delay Window Section .............................................................. 10 Changes to Channel Divider Window Section........................... 11 Changes to Output Driver Window Section............................... 12 Changes to Load Setup Section, Select Evaluation Board Section, Configure Serial Port Section, Debug Section, and Operational Modes Menu Section ............................................... 13 Changes to AD9520 PLL Loop Filter Section............................. 14 Changes to Using the Evaluation Board to Program an AD9520 on a Customer Board Section ....................................................... 15 Changes to AD9520 Binary File Generation Section and Avoiding Checksum Mismatches Section ................................... 16 1/2010—Revision 0: Initial Version Rev. A | Page 2 of 16 Evaluation Board User Guide UG-076 EVALUATION BOARD HARDWARE Connect an oscilloscope, spectrum analyzer, or other lab equipment to any of the J0 to J9 SMA connectors on the right side of the board. The following instructions are for setting up the physical connections to the AD9520 evaluation board. When connecting the evaluation board to a PC for the first time, the user must install the evaluation software prior to connecting the evaluation board. POWER AND PC CONNECTIONS Perform the following steps, in order, to begin using the evaluation board. 1. 2. 3. 4. Install the AD9520 evaluation software. Administrative privileges are required for installation. The 64-bit versions of Windows® are not supported. Connect the wall power supply to the main power connector, labeled P2. The following five LEDs then turn on: CR1 (USBSTAT), CR7 (VS), CR8 (VS-CP), CR9 (VS_USB), and CR10 (VS_LVPECL). Connect the USB cables to the evaluation board and the PC. The LED labeled CR2 (VBUS) on the AD9520 evaluation board illuminates and the CR1 (USBSTAT) LED starts blinking. If the Found New Hardware Wizard window automatically appears when the evaluation board is connected, select Install the software automatically and click Next. The Found New Hardware Wizard window may appear twice, and a system restart may be required. • To bypass the wall power supply, remove the following ferrite beads (on the backside of the board): F7, F4, F2, and F6. Next, connect a bench power supply to TB1 on the evaluation board. Bypassing is useful for making AD9520 power consumption measurements. BYPASSING THE PLL (CLOCK DISTRIBUTION ONLY) To bypass the PLL, connect a signal generator to the SMA connector labeled CLK. By default, this connection is ac-coupled to the CLK pin, and terminated with 50 Ω to ground. Refer to the Evaluation Software Components section for details on running the AD9520 evaluation board software. USING AN EXTERNAL VCXO 1. 2. If the USBSTAT LED is not blinking, ensure that • BYPASSING THE WALL POWER SUPPLY To use an external VCXO, Refer to the Evaluation Board Software section for details on running the AD9520 evaluation board software. • OUT0 through OUT8 are ac-coupled low voltage positive emitter coupled logic (LVPECL) outputs. OUT9 through OUT11 are dc-coupled and have no output termination. These outputs are intended to allow the user to evaluate the AD9520 output driver in complementary metal-oxide semiconductor (CMOS) mode. To use OUT9 through OUT11 in LVPECL mode, replace the 0 Ω resistors with 0.1 µF capacitors, and install 200 Ω pull-down resistors. Jumpers are installed on Position S1 and on the SPI position of S2. The jumper on S4 is across the center pin and the minus symbol. The USB port on the PC is operational and that the USB cable is not damaged. SIGNAL CONNECTIONS To connect signals, connect a signal generator to the J10 SMA connector. By default, the reference inputs on this evaluation board are ac-coupled and terminated with 50 Ω to ground. An amplitude setting of 0 dBm to 6 dBm is acceptable. To connect a signal to REF2, connect that signal to the J13 SMA connector. DC-coupling is recommended in applications requiring automatic hitless reference switching. There is a possibility that the AD9520 receive buffer can chatter when an ac-coupled clock stops toggling. 3. Install a 0 Ω resistor at R9 and remove R8. Connect a loop filter and the external VCO/VCXO input to J12. Connect the external VCO/VCXO output to the J11 SMA connector (CLK input). USING I2C SERIAL PORT MODE To use I2C serial port mode, 1. 2. 3. 4. 5. Rev. A | Page 3 of 16 Move Jumper S2 to the center and left (I2C) pins. Move Jumper W1 to the center and left (I2C) pins. Select the desired I2C address using Jumper S5 and Jumper S6. Note that S5 = S6 = high is reserved for SPI mode. In the evaluation software, click Configure Serial Port from the I/O menu (see Figure 24). Click Reset Serial Port, and then click Detect Current Configuration. A dialog box appears and acknowledges the I2C mode and address. UG-076 Evaluation Board User Guide EVALUATION BOARD SOFTWARE SOFTWARE INSTALLATION Do not connect the evaluation board until the software installation is complete. 1. 2. 3. The latest evaluation software and documentation can be downloaded from the Analog Devices website. If the software was downloaded, skip to Step 3. If using the CD, insert the AD9520 evaluation software CD. Doubleclick My Computer, and then double-click the AD9520EV CD icon. A window opens showing the contents of the CD divided into four sections: Datasheet, Layout, Schematic, and Software. The file named readme.txt contains a description of the CD contents and may contain additional as well as any last minute instructions or information. Doubleclick the Software folder. Double-click AD9520Eval_Setup1.1.0.exe. (Note that the website may have a newer version.) Follow the installation instructions. The default installation location for the evaluation software is C:\Program Files\Analog Devices\AD9520 Eval Software\. See the Evaluation Board Hardware section for instructions to connect the evaluation board. Alternatively, the user can use the software in standalone mode, and specify which version of the AD9520 is used. The standalone mode is useful for verifying register settings for a given PLL setup. If the evaluation board is connected while the evaluation software is running, the window in Figure 2 appears to prompt the user to load the evaluation board with the evaluation software settings or read the evaluation board with the evaluation software settings. 08746-002 Use the following instructions to set up the AD9520 evaluation board software. Figure 2. SYNC Evaluation Software Window Power up and connect the evaluation board to the PC. See the Evaluation Board Hardware section for details on the various connectors on the evaluation board. 1. 2. Double-click AD9520 Eval Software to run the AD9520 evaluation software. Depending on whether the evaluation board was found by the software, either light blue text appears in a pop-up window indicating that the evaluation board was found, or red text appears indicating that the evaluation board was not found. If the evaluation board is found, click anywhere in the popup window with the Evaluation Software Ready message, and the main window for the software appears. Proceed to the Evaluation Software Components section for details about running the software. If the evaluation board is not found, a dialog box appears allowing the user to select which AD9520 evaluation board is connected while the software runs in standalone mode. Standalone mode is useful for viewing and generating register setup files. If the evaluation board was not automatically detected when it was connected, the user can also click Select Evaluation Board from the I/O menu (see Figure 24), and select Ezssp-0, Ezssp-1, or Ezssp-2. 08746-003 RUNNING THE SOFTWARE Figure 3. Select USB Device Window See the Evaluation Software Components section for a description of the evaluation software features, or the Quick Start Guide to the AD9520 PLL section for details on the individual blocks of the AD9520. Rev. A | Page 4 of 16 Evaluation Board User Guide UG-076 QUICK START GUIDE TO THE AD9520 PLL When the evaluation software is installed, the evaluation board is connected, and the software is loaded, use the following steps to configure and lock the PLL. These steps assume that the input signal is present, the evaluation board has not been modified, and that the PLL loop filter is suitable for the user’s application. This quick start guide covers only simple PLL operation to start the PLL. See the AD9520 data sheet and Evaluation Software Components section for a detailed explanation of the various AD9520 features. The following case is an example for the AD9520-4 using the values in Table 1. Table 1. Default Parameter Values 2. 3. 08746-004 Figure 5. Reference Input Control Window 4. Turn the PLL on by selecting Normal Op from the PLL MODE box found at the top of the main window (see Figure 8). Enter the intended reference input frequency (in megahertz) in the REF 1 (MHz) box at the upper left corner of the main window. Click the triangular buffer symbol immediately to the right of the input reference frequency text boxes (see Figure 4) to open the Reference Input Control window shown in Figure 5. Turn the REF1 reference input buffer on by selecting the Enable REF 1 check box, and then click OK. 5. When the window closes, the WRITE button under the REGISTER W/R section in Figure 8 blinks red. This indicates that there are settings that have not been loaded to the AD9520 evaluation board. Click the blinking red WRITE button to load these settings to the evaluation board. Select the VCO as the input to the clock distribution circuitry by clicking the mux symbol that is located immediately to the right of the VCO (MHz) box (see Figure 6). Figure 6. Mux Symbol 6. 08746-024 1. Value 19.44 MHz on REF1 148.5 MHz 72 270 kHz 5500 1485 MHz 2 5 08746-025 Parameter Input Frequency Output Frequency Reference Divider Phase Detector Frequency Feedback Divider VCO Frequency VCO Divider Channel Divider Figure 4. Buffer Symbol Rev. A | Page 5 of 16 When the VCO is selected, the border of the VCO (MHz) box changes from gray to black. The current VCO frequency is shown in the VCO (MHz) box. UG-076 Evaluation Board User Guide Program the R (reference) divider by clicking the R DIVIDER box at the top of the main window. Set the desired value and click OK (see Figure 13). 8. Program the N (feedback) divider by clicking the N DIVIDER box at the top of the main window. Set the desired value and click OK. For this example, N = 5500 can use 8/9 dual modulus mode with A = 4 and B = 687. 9. Set the charge pump current (1.2 mA in this case) by clicking the CHARGE PUMP box in the upper right corner of the main window, and click OK. 10. Note that if the desired configuration has the a phase detector frequency above 50 MHz, an antibacklash pulse width of 1.3 ns may work better. This setting is accessed by clicking the PFD box to the left of the CHARGE PUMP box. However, this setting normally does not need to be modified. 11. Set the VCO divider by clicking the green VCO box in the center of the main window immediately to the left of the Cal VCO button. 12. Power down unused drivers by clicking the numbered triangular symbol (see Figure 7) on the right side of the main window, and then clicking Safe Power Down. 08746-026 7. Figure 7. Driver Symbol 13. Set the channel dividers by clicking DIVIDER 0 through DIVIDER 3, and entering the divider ratio. 14. Click the flashing red WRITE button under the REGISTER W/R section. This loads the desired settings to the AD9520 evaluation board. 15. Click the blinking yellow Cal VCO button to open the VCO calibration window. The default VCO divide ratio (16) works for all applications. Click the Cal VCO button in the Calibrate VCO window to begin calibration (see Figure 19). The PLL is now locked and the lock detect (LD) LED on the left side of the board is on. Rev. A | Page 6 of 16 Evaluation Board User Guide UG-076 EVALUATION SOFTWARE COMPONENTS 08746-005 MAIN WINDOW Figure 8. Evaluation Software Main Window The AD9520 evaluation software is composed of subsections that correspond to the major functional blocks of the AD9520. These subsections are listed in the following sections, and each of these subsections has its own window. From the main window, each functional block can be accessed by clicking that block in the main window. When a subwindow closes after clicking OK, the WRITE box on the main window (under the REGISTER W/R section) may blink red. This indicates that there are settings that have not been loaded to the AD9520 evaluation board. Clicking the blinking red WRITE box loads these settings to the evaluation board. Rev. A | Page 7 of 16 UG-076 Evaluation Board User Guide PLL CONFIGURATION WINDOW The Reference Input Control window is shown in Figure 10 and is accessed by clicking either of the triangular buffer symbols immediately to the right of the REF 1 (MHz) and REF 2 (MHz) input reference frequency boxes (see Figure 9). The PLL Configuration window shown in Figure 11 is opened by clicking the Config PLL button on the main screen. The window has three sections: SyncB Counter Reset Mode, PLL Status Registers, and Settings. 08746-024 PLL REFERENCE INPUT WINDOW 08746-007 Figure 9. Buffer Symbol Figure 11. PLL Configuration Window 08746-006 The SyncB Counter Reset Mode section indicates whether the R, A, and B counters are reset when the SYNC pin is activated, and controls Register 0x019, Bits[7:6]. See the AD9520 data sheet for more details. Figure 10. Reference Input Control Window This window is used to enable the PLL reference inputs, which are powered down by default. Select Enable REF 1, Enable REF 2, or both to enable the appropriate reference input and click OK when finished. If a differential input is used, select the Use Differential Ref Mode (Unchecked = Single-Ended Mode) check box. Note that this mode must not be used simultaneously with Enable REF 1 or Enable REF 2. The remaining six check boxes control the reference switchover modes. If Disable Switchover De-Glitch is activated, the AD9520 maintains the phase relationship between the active input and PLL output during a reference switchover. Otherwise, the AD9520 minimizes the phase disturbance at the output during a reference switchover. The user must check Enable XTAL Oscillator if intending to connect a crystal to the reference input. Enable PLL CMOS Ref Input DC Offset forces the dc bias point of the single-ended reference input to be different from the switching point, and is useful for preventing an ac-coupled input from chattering when the reference input is lost. The PLL Status Registers section allows the user to see the current value of the readonly PLL status register, Address 0x01F. This function is useful for ensuring that the AD9520 VCO has finished VCO calibration, and that the PLL is locked. The Settings section controls the various PLL settings such as holdover. The AD9520 data sheet describes these functions in detail. REFMON, STATUS, AND LD BUTTONS These three blue buttons (REFMON, STATUS, and LD) allow the user to select which signals appear at the REFMON, STATUS, and LD pins at Connector P1. Connector P1 is located in the center of the evaluation board. The pins in the left column of Connector P1 are ground pins, and the ones in the right column are signal pins. There are many useful diagnostic signals available at these pins. The R divider output is particularly useful. In the example used in the Quick Start Guide to the AD9520 PLL section, the 80 kHz signal is visible on the STATUS pin to ensure that the reference inputs and R divider are working properly. Dynamic signals (such as the R divider output) are primarily intended for diagnostics. These diagnostic signals may adversely affect PLL performance in critical applications if left on in normal operation. Rev. A | Page 8 of 16 Evaluation Board User Guide UG-076 REGISTER W/R BOX The REGISTER W/R (write/read) box has three buttons and three check boxes. The WRITE button transfers the values stored in the evaluation software to the evaluation board. It blinks red when register values have changed. The READ button transfers the values stored in the evaluation board to the evaluation software. The UPDATE button issues an I/O update command by writing 0x01 to Register 0x232. Selecting the All check box transfers all of the registers when the WRITE button is clicked. When this box is cleared, only the registers whose value has changed are written. Selecting the Auto check box adjacent to the WRITE box forces the evaluation software to write the register changes to the evaluation board automatically when they occur. To load the values stored in the EEPROM, ensure that the EEPROM pin is pulled high and reset the AD9520. The EEPROM pin is pulled high by placing the S4 EEPROM jumper (located in the lower left corner of the evaluation board) across the center and right (high) pin. The user can reset the AD9520 by clicking the red RESET button in the lower left corner of the main window, and selecting Strobe ResetB. REFERENCE (R) DIVIDER WINDOW The R divider window shown in Figure 13 is accessed by clicking the R DIVIDER box in the main window. It allows the user to set the reference divider. If this box is colored gray, the PLL is off. To turn the PLL on, click the PLL MODE box at the top of the main window, and select Norm Op. 08746-009 Selecting the Auto check box adjacent to the UPDATE box forces the evaluation software to issue an I/O update command whenever registers are written to the AD9520. SYNC, PD (POWER DOWN), AND RESET BUTTONS The SYNC, PD, and RESET buttons allow the user to control the SYNC, PD, and RESET pins on the AD9520. Each button has three options: Strobe, Latch, and Release. Strobe activates the pin, and then releases it. Latch holds the pin active until the Release command is issued. EEPROM CONTROL WINDOW This window has a check box for holding the R divider in reset. When the R divider is held in reset, the PLL loop is opened. Therefore, this feature is seldom used. The reference input path also has a reference multiply-by-2 (labeled X2 in the main window) check box that controls the reference clock doubler. This frequency doubler can be used to double the phase detector frequency of the PLL, and is described in detail in the AD9520 data sheet. 08746-008 The EEPROM Control window shown in Figure 12 is accessed by clicking the EEPROM button near the lower left corner of the main window. Figure 13. Reference Divider Window Figure 12. EEPROM Control Window To store the current register settings of the AD9520 to the EEPROM, click the Program EEPROM button (see Figure 12). Check the EEPROM Status Registers section on the right side of the window to verify that the operation is successful. Rev. A | Page 9 of 16 UG-076 Evaluation Board User Guide R AND N DELAY WINDOW The N Divider window shown in Figure 14 is accessed by clicking the N DIVIDER box. It allows the user to set the feedback divider. If this box is colored gray, the PLL is off. To turn the PLL on, click the PLL MODE box at the top of the main window and select Norm Op. The N delay window shown in Figure 15 is accessed by clicking the N DELAY box on the main window. The R DELAY box is identical to the N DELAY box. These delay settings, which are most often used in zero delay mode, allow the user to vary the static phase offset of the PLL. 08746-011 08746-010 FEEDBACK (N) DIVIDER WINDOW Figure 14. N Divider Window Figure 15. N Delay Window The evaluation software has internal checking to ensure that invalid settings are not programmed. For example, the B counter must always be larger than the A counter. Another restriction is that 8/9 dual modulus mode cannot be used for VCO frequencies greater than 2400 MHz. In cases where a feedback divider restriction cannot be resolved, the user may need to adjust the R (reference) divider to allow a different feedback divider value. For example, it is not possible to use the internal VCO and a feedback divider of 30. However, the R divider can be doubled, which allows a feedback divider of 60. The feedback divider window has a check box for holding the N divider in reset. When the N divider is held in reset, the PLL is open. Therefore, this feature is seldom used. PHASE FREQUENCY DETECTOR (PFD) WINDOW The Phase Frequency Detector (PFD) window shown in Figure 16 is accessed by clicking the PFD box in the main window. 08746-012 The various modes of the N divider are described in detail in the AD9520 data sheet. For most applications, the 8/9 or 16/17 dual modulus modes are used. For applications requiring a divider value larger than 131119, the 32/33 mode is provided. Different applications require different settings, and the user can experiment with the different settings. Figure 16. Phase Frequency Detector Window The features accessible in this window are described in detail in the AD9520 data sheet. The most commonly used settings are Anti-Backlash Pulse Width and Lock Detect Counter. For phase detector frequencies greater than 50 MHz, the PLL may work better with the 1.3 ns antibacklash pulse width setting. Setting the Lock Detect Counter to values greater than 5 PFD cycles can be useful in applications where the loop bandwidth is low and the lock detect counter chatters during acquisition. Rev. A | Page 10 of 16 Evaluation Board User Guide UG-076 VCO CALIBRATION WINDOW The Charge Pump Setup window shown in Figure 17 is accessed by clicking the CHARGE PUMP box in the main window. The Calibrate VCO window shown in Figure 19 is accessed by clicking the Cal VCO button in the main window. 08746-013 08746-015 CHARGE PUMP SETUP WINDOW Figure 19. Calibrate VCO Window Figure 17. Charge Pump Setup Window This window is most often used to vary the charge pump current. A valid reference input signal must be present to complete VCO calibration, and the VCO must be recalibrated any time the VCO frequency changes by more than 40 MHz. The window also has a check box for setting the charge pump voltage to VCP/2, which is useful for debugging the PLL and isolating the output driver section of the AD9520 from the PLL section. A VCO divider of 16 is suitable for all applications. However, for applications where the phase detector frequency is