Analog Devices UG-160, Руководство пользователя

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UG-160 Evaluation Board User Guide
Rev. B | Page 4 of 16
EVALUATION BOARD HARDWARE
The evaluation board comes with a mini-USB cable to connect
the evaluation board to the USB port of a PC. The evaluation
board silkscreen is shown in Figure 2. The
EV-ADF4108EB1Z
schematics are shown in Figure 7 to Figure 10.
POWER SUPPLIES
The board is powered via two external supplies, 5.5 V and 15 V,
and connected as described in the Quick Start Guide section.
INPUT SIGNALS
The necessary reference input can be supplied from an external
generator. A low noise, high slew rate reference source is best for
achieving the stated performance of the
ADF4108 . This reference
source is connected to the REFIN SMA connector. A second
option is to solder a footprint-compatible TCXO to Footprint Y1.
OUTPUT SIGNALS
The VCO output is available at EXT_VCOOUT through a
standard SMA connector. A divide-by-2 option is also available
at the VCO/2 SMA connector. To use an alternate loop filter
and VCO, the charge pump output (CPOUT) and the VCO
tune voltage (VTUNE) are available as outputs via standard
SMA connectors.
DEFAULT OPERATION
All components necessary for local oscillation (LO) generation
can be inserted on the board. The board is shipped with the
ADF4108 synthesizer, an active loop filter, and the VCO.
An active loop filter using standard feedback is inserted between
the charge pump output and the VCO input. The design para-
meters for the loop filter are for a center frequency of 6400 MHz,
a PFD frequency of 2500 kHz, and an active loop filter bandwidth
of 15 kHz. To design a filter for different frequency setups, use
the
ADIsimPLL simulation software to generate filter component
values and evaluate results.
09145-
002
Figure 2. Evaluation Board Silkscreen