ANALOG DEVICES UG-109 Service Manual

Evaluation Board User Guide

One Technology Way • P. O . Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel : [phone] • Fax : [phone] • www.analog.com

UG-109

Evaluation Board for Fractional-N/Integer-N PLL Frequency Synthesizer

FEATURES

Self-contained board including PLL, VCO, loop filter (35 kHz),

25 MHz TCXO reference, USB interface, and voltage
regulators

Accompanying software allows control of synthesizer

functions from a PC
Choice of power supply via USB or external feeding
Typical phase noise performance of −99 dBc/Hz @ 1 kHz

offset from carrier (1 GHz output frequency)

GENERAL DESCRIPTION

The EVAL-ADF4350EB1Z is designed to evaluate the perfor­mance of the ADF4350 frequency synthesizer. A digital picture

DIGITAL PICTURE OF EVALUATION BOARD

of the board is shown in Figure 1. It contains the ADF4350
synthesizer, a USB connector and related interface, a 25 MHz
TCXO reference source, SMA connectors for the RF outputs,
and reference signal plus headers for various signals and
voltages. There is also a loop filter (35 kHz) on board. A USB
cable is included with the board to connect to a PC USB port.

The package also contains Windows® software (2000- and XP­compatible) to allow easy programming of the synthesizer.

EVALUATION KIT CONTENTS

Evaluation board software CD
USB cable
EVAL-ADF4350EB1Z

PLEASE SEE THE LAST PAGE FOR AN IMPORTANT
WARNING AND LEGAL TERMS AND CONDITIONS.

Figure 1.

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UG-109 Evaluation Board User Guide

TABLE OF CONTENTS

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

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

Evaluation Kit Contents ................................................................... 1

Digital Picture of Evaluation Board ............................................... 1

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

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

Overview ........................................................................................ 3

Power Supplies .............................................................................. 3

REVISION HISTORY

3/10—Revsion 0: Initial Version

RF Output .......................................................................................3

Loop Filter ......................................................................................3

Reference Source ...........................................................................3

Evaluation Setup ................................................................................4

Evaluation Board Software ...............................................................5

Evaluation Board Schematics and Artwork ...................................6

Ordering Information .................................................................... 10

Bill of Materials ........................................................................... 10

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Evaluation Board User Guide UG-109

EVALUATION BOARD HARDWARE

OVERVIEW

The EVAL-ADF4350EB1Z comes with a cable for connecting to
the USB port of a PC. The silk screen for the evaluation board is
shown in Figure 8. The board schematic is shown in Figure 5,
Figure 6, and Figure 7.

POWER SUPPLIES

The EVAL-ADF4350EB1Z can be powered either from the
USB port or via dc power connectors (4 mm banana connec­tors). When feeding via banana connectors, 3.75 V to 5.5 V is
a suitable feeding voltage. The power supply circuitry allows
the user to use one or two separate LDOs to feed the ADF4350
(using fewer LDOs increases the risk of spur contaminated dc
feeds). Consult the board schematic in Figure 5, Figure 6, and
Figure 7 to determine a suitable setting.

An LED, D6, indicates when USB power is available, and
another LED, D5, indicates when the ADF4350 is powered.
Switch S1 is used to power the ADF4350 from the external
dc connectors USB port and Switch S2 to power from the
USB port.

In case the USB processor or clock causes spurs on the RF
output signal, the user may feed the evaluation board via the
dc connectors and unplug the USB cable, thereby removing
power from the USB interface circuitry. There is also a
grounded frame surrounding the USB interface circuitry
to allow mounting of a shielding box.

RF OUTPUT

The EVAL-ADF4350EB1Z has two SMA output connectors
(differential outputs). The device is quite sensitive to impedance
unbalance. If only one port of a differential pair is used, termi­nate the other with a 50 Ω load. If the user wishes to utilize the
auxiliary outputs, use the EVAL-ADF4350EB2Z.

LOOP FILTER

The loop filter schematic is included in the board schematic on
Figure 5. The loop filter component placements are clarified in
Figure 2.

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Figure 2. Loop Filter Placement

REFERENCE SOURCE

The 25 MHz TCXO from Rakon Limited provides the necessary
reference signal. An external REFIN may be used if desired. In
this case, disable the on-board TCXO by removing R1 and R2.
R9 can be populated with 50 Ω to adjust impedance matching
of the evaluation board to the external reference source.

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UG-109 Evaluation Board User Guide

EVALUATION SETUP

REFERENCE (OPTIONAL)

REFERENCE IN/
REFERENCE OUT

PC

USB CRYSTAL

AND PROCESSOR

LOCK DETECT LED

EXTERNAL DC

SUPPLY

EXTERNAL DC

GND

USB

POWER

LED

EXTERNAL
POWER
SWITCH

USB
POWER
SWITCH

PLL

POWER

LED

TCXO

ADF4350

50Ω

TERMINATION

LOOP

FILTER

SPECTRUM
ANALYZER

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Figure 3. Evaluation Setup

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