Analog Devices UG-002 - Manual

Evaluation Board User Guide
UG-002
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
Evaluating the AD9551 Multiservice Clock Generator
See the last page for an important warning and disclaimers. Rev. 0 | Page 1 of 12
FEATURES
Simple power connection using USB connection and
on-board LDO voltage regulators
LDOs are easily bypassed for power measurements
AC-coupled differential LVPECL SMA connectors
SMA connectors for
2 reference inputs
2 PLL lock detect outputs
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
USB computer interface
Dip switch configurable for manual operation
Software calculator provides flexibility, allowing programming
almost any rational input/output frequency ratio
GENERAL DESCRIPTION
This user guide describes the hardware and software of the
AD9551 evaluation board and includes detailed schematics and
PCB layout artwork. The AD9551 Revision D evaluation board
is a compact, easy to use platform for evaluating all features of the
AD9551 multiservice clock generator.
The AD9551 accepts one or two reference input signals to
synthesize one or two output signals. The AD9551 uses a
fractional-N PLL that precisely translates the reference frequency
to the desired output frequency. The input receivers and output
drivers provide both single-ended and differential operation.
Reference conditioning and switchover circuitry internally
synchronizes the two references so that if one reference fails,
there is virtually no phase perturbation at the output.
The AD9551 uses an external crystal and an internal DCXO to
provide for holdover operation. If both references fail, the device
maintains a steady output signal. This may mislead you to believe
that the PLL is locked and the board is configured properly. A
simple test is to move the input REF A or REF B clock a few kilo-
hertz and verify that the changes in output frequency track the input.
DIGITAL PICTURE OF THE EVALUATION BOARD
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Figure 1. AD9551 Evaluation Board, Revision D