ANALOG DEVICES UG-076 Service Manual

Evaluation Board User Guide

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UG-076

AD9520-x Evaluation Board

FEATURES

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

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

GENERAL DESCRIPTION

The AD9520-x (hereafter referred to as AD9520) is a very low noise PLL clock synthesizer featuring an integrated VCO, clock dividers, and up to 24 outputs. The AD9520 features automatic holdover and a flexible reference input circuit allowing for very smooth reference clock switching. The AD9520 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. This user guide covers all six versions of the AD9520 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.

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 LVDS outputs, is covered in 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 sheet and software documentation available at www.analog.com.

AD9520 EVALUATION BOARD

Figure 1.

See the last page for an important warning and disclaimers. Rev. 0 | Page 1 of 16

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UG-076 Evaluation Board User Guide

Features .............................................................................................. 1

Applications ....................................................................................... 1

General Description ......................................................................... 1

AD9520 Evaluation Board ............................................................... 1

Revision History ............................................................................... 2

Evaluation Board Hardware ............................................................ 3

Power and PC Connections ........................................................ 3

Signal Connections ...................................................................... 3

Bypassing the Wall Power Supply ............................................... 3

Bypassing the PLL (Clock Distribution Only) ............................. 3

Using an External VCXO ............................................................ 3

Using I2C Serial Port Mode ......................................................... 3

Evaluation Board Software .............................................................. 4

Software Installation .................................................................... 4

Running the Software .................................................................. 4

Quick Start Guide to the AD9520 PLL .......................................... 5

Evaluation Software Components .................................................. 7

Main Window ............................................................................... 7

PLL Reference INput Window .................................................... 8

PLL Configuration Window ....................................................... 8

REFMON, STATUS, and LD Buttons ........................................ 8

SYNC, PD (Power Down), and RESET Buttons .......................9

EEPROM Control Window .........................................................9

Reference (R) Divider Window ...................................................9

Feedback (N) Divider Window ................................................ 10

R and N Delay Window ............................................................. 10

Phase Frequency Detector (PFD) Window ............................ 10

Charge Pump Setup Window ................................................... 11

Zero Delay Window ................................................................... 11

VCO Calibration Window ........................................................ 11

Channel Divider Window ......................................................... 11

Output Driver Window ............................................................. 12

Debug Window ........................................................................... 12

Evaluation Software Menu Items.................................................. 13

Menu Bar ..................................................................................... 13

AD9520 PLL Loop Filter ............................................................... 14

Using the Evaluation Board to Program an AD9520 on a

Customer Board .............................................................................. 15

AD9520 Binary File Generation ................................................... 16

Checksum Generation ............................................................... 16

Avoiding Checksum Mismatches ............................................. 16

ESD Caution................................................................................ 16

REVISION HISTORY

1/10—Revision 0: Initial Version

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Evaluation Board User Guide UG-076

EVALUATION BOARD HARDWARE

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

1. Install AD9520 evaluation software. Administrative

privileges are required for installation. The 64-bit versions of Windows® are not supported.

2. Connect the wall power supply to the main power

connector labeled P2. The following five LEDs should be on: CR1 (USBSTAT), CR7 (VS), CR8 (VS-CP), CR9 (VS_USB), and CR10 (VS_LVPECL).

3. Connect the USB cables to the evaluation board and the

computer. The red LED labeled CR2 (VBUS) on the AD9520 evaluation board should illuminate and the CR1 (USBSTAT) LED should start blinking.

4. 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.

Refer to the Evaluation Board Software section for details on running the AD9520 evaluation board software.

If the USBSTAT LED is not blinking, ensure that:

• 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 50  to ground. An amplitude setting of 0 dBm to 6 dBm is fine.

If the user wishes 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.

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.

OUT0 through OUT8 are ac-coupled LVPECL outputs. OUT9 through OUT11 are dc-coupled and have no output termination. These are intended to allow the user to evaluate the AD9520 output driver in CMOS mode. To use OUT9 through OUT11 in LVPECL mode, replace the 0  resistors with 0.1 µF capacitors, and install 200  pull-down resistors.

BYPASSING THE WALL POWER SUPPLY

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. This 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  to ground. Refer to the Evaluation Software Components section for details on running the AD9520 evaluation board software.

USING AN EXTERNAL VCXO

To use an external VCXO,

1. Install a 0 Ω resistor at R9 and remove R8.

2. Connect a loop filter and external VCO/VCXO input to J12.

3. 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. Move Jumper S2 to the center and left (I

2. Move Jumper W1 to the center and left (I

3. Select the desired I

Jumper S6. Note that S5 = S6 = high is reserved for SPI mode.

4. On the evaluation software, select Configure Serial Port

from the I/O menu (see Figure 24).

5. Click Reset Serial Port, and then click Detect Current

Configuration. A dialog box appears and acknowledges

the I

C mode and address.

C address using Jumper S5 and

C) pins.

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UG-076 Evaluation Board User Guide

EVALUATION BOARD SOFTWARE

Use the following instructions to set up the AD9520 evaluation board software.

SOFTWARE INSTALLATION

Do not connect the evaluation board until the software installation is complete.

1. The latest evaluation software and documentation can be

downloaded from www.analog.com.

2. 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 descrip- tion of the CD contents and may contain additional as well as any last minute instructions or information. Doubleclick the Software folder.

3. 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\.

RUNNING THE SOFTWARE

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. 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.

2. If the evaluation board is found, click anywhere in the pop-

up window with the Evaluation Software Ready, 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 you 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.

See the Evaluation Board Hardware section for connecting the evaluation board. Alternatively, you can use the software in standalone mode, and specify which version of the AD9520 will be 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 you to load the evaluation board with the evaluation software settings or read the evaluation board with the evaluation software settings.

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Figure 2. SYNC Evaluation Software Window

If the evaluation board was not automatically detected when it was connected, you can also select the Select Evaluation Board option from the I/O menu (see Figure 24), and select Ezssp-0, Ezssp-1, or Ezssp-2.

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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.

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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 Tabl e 1.

Table 1.

Parameter Value

Input Frequency 19.44 MHz on REF1 Output Frequency 148.5 MHz Reference Divider 72 Phase Detector Frequency 270 kHz Feedback Divider 5500 VCO Frequency 1485 MHz VCO Divider 2 Channel Divider 5

1. Turn the PLL on by selecting Normal Op from the PLL

MODE box found at the top of the main window (see

Figure 8).

2. Enter the intended reference input frequency (in

megahertz) in the REF 1 (MHz) box at the upper left corner of the main window.

3. Click the triangular buffer symbol immediately to the

right of the input reference frequency (see Figure 4) text boxes to load 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.

Figure 5. Reference Input Control Window

4. When the window closes, the WRITE button under the

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.

5. 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).

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Figure 6. Buffer Symbol

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.

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Figure 4. Buffer Symbol

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