Datasheet

UG-104 Evaluation Board User Guide
Rev. B | Page 4 of 16
EXTERNAL INDUCTOR OPTIONS
The ADF4360-7 uses external inductors (L1 and L2) to set up
the LC tank circuit of the VCO. The evaluation board has a
footprint for placing these inductors. A value of 3.9 nH is inserted
on the board giving a VCO center frequency of 900 MHz. For
this inductor value and for other inductor values of greater than
3.3 nH, a 470 Ω resistor in parallel to ground for both L1 and L2
must be inserted, as shown in Figure 3.
08891-004
Figure 3. External Inductors and Resistors for ADF4360-7 Tank Circuit
To find the optimum frequency range for a given inductor, see
Figure 4. Ensure that the desired frequency is between the two
lines and read off the appropriate inductance needed.
300
500
400
1200
1300
1400
1000
1100
800
900
600
700
1500
0 5 10 15 20 3025
EXT INDUCTANCE (nH)
FREQUENCY (MHz)
08891-005
Figure 4. Output Center Frequency vs. External Inductor Value