CN-0147 Datasheet, PDF (4/4 Pages) Analog Devices – Powering a Fractional-N Voltage Controlled Oscillator with Low Noise LDO Regulators for Reduced Phase Noise

CN-0147
COMMON VARIATIONS
Additional regulators can be added for greater isolation
between power supplies, if desired. Also, one ADP150
regulator can be used to power the entire ADF4350 part.
However, care needs to be taken in this case to ensure the
maximum rated current of the single ADP150 regulator is not
exceeded. This is possible if the lowest output power setting
on the ADF4350 is selected.
CIRCUIT EVALUATION AND TEST
This circuit note, CN-0147, uses the EVAL-ADF4350EB1Z
board for evaluation of the described circuit, allowing for quick
setup and evaluation. The EVAL-ADF4350EB1Z board uses the
standard ADF4350 programming software, contained on the
CD that accompanies the evaluation board.
Equipment Needed
Windows® XP, Windows, Vista (32-bit), or Windows 7 (32-bit)
PC with USB Port, the EVAL-ADF4350EB1Z, the ADF4350
programming software, 5.5 V power supply, and a spectrum
analyzer such as a Rhode and Schwartz FSUP26. See this circuit
note CN-0147 and UG-109 user guide for evaluation board
EVAL-ADF4350EB1Z and the ADF4350 data sheet.
Getting Started
This circuit note, CN-0147, contains a description of the circuit,
the schematic, and a block diagram of the test setup. The ser
guide, UG-109, details the installation and use of the EVAL-
ADF4350 evaluation software. UG-109 also contains board
setup instructions and the board schematic, layout, and bill of
materials.
Functional Block Diagram
This circuit note, CN-0147, contains the function block
diagram of the described test setup in Figure 3.
Setup and Test
After setting up the equipment, standard RF test methods
should be used to measure the spectral purity of the output
signal.
Circuit Note
LEARN MORE
CN0147 Design Support Package:
http://www.analog.com/CN0147-DesignSupport
ADIsimPLL Design Tool
ADIsimPower Design Tool
Basso, C., C. Fourtet, and P. Kadanka. “Get the Best from Your
Low-Dropout Regulator.” EDN, 18 Feb. 1999.
Data Sheets and Evaluation Boards
ADF4350 Data Sheet
ADF4350 Evaluation Board
ADP150 Data Sheet
ADP3334 Data Sheet
REVISION HISTORY
6/11—Rev. B to Rev. C
Changes to Circuit Description.......................................................2
11/10—Rev. A to Rev. B
Added Evaluation and Design Support Section ............................1
Added Circuit Evaluation and Test Section ...................................4
7/10—Rev. 0 to Rev. A
Changes to Figure 1...........................................................................1
Changes to Figure 3...........................................................................2
4/10—Revision 0: Initial Version
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