ADF4360-9BCPZ Analog Devices Inc, ADF4360-9BCPZ Datasheet - Page 20

• Manufacturer Part Number: ADF4360-9BCPZ
• Description: Synthesizer And VCO
• Manufacturer: Analog Devices Inc
• Type: Fanout Distribution, Integer N Synthesizer (RF)r

Specifications of ADF4360-9BCPZ

• Pll: Yes
• Input: CMOS
• Output: Clock
• Number Of Circuits: 1
• Ratio - Input:output: 1:2
• Differential - Input:output: No/No
• Frequency - Max: 400MHz
• Divider/multiplier: Yes/No
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-LFCSP
• Frequency-max: 400MHz
• Number Of Elements: 1
• Supply Current: 5mA
• Pll Input Freq (min): 10MHz
• Pll Input Freq (max): 250MHz
• Operating Supply Voltage (typ): 3.3V
• Operating Temp Range: -40C to 85C
• Package Type: LFCSP EP
• Output Frequency Range: 1.1 to 400MHz
• Operating Supply Voltage (min): 3V
• Operating Supply Voltage (max): 3.6V
• Operating Temperature Classification: Industrial
• Pin Count: 24
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADF4360-9
APPLICATIONS
CHOOSING THE CORRECT INDUCTANCE VALUE
The ADF4360-9 can be used at many different frequencies
simply by choosing the external inductors to give the correct
output frequency. Figure 27 shows a graph of both minimum
and maximum frequency vs. the external inductor value. The
correct inductor should cover the maximum and minimum
frequencies desired. The inductors used are 0603 CS or 0805 CS
type from Coilcraft. To reduce mutual coupling, the inductors
should be placed at right angles to one another.
The lowest center frequency of oscillation possible is approximately
65 MHz, which is achieved using 560 nH inductors. This
relationship can be expressed by
where:
f
L
The approximate value of capacitance at the midpoint of the
center band of the VCO is 9.3 pF, and the approximate value of
internal inductance due to the bond wires is 0.9 nH. The VCO
sensitivity is a measure of the frequency change vs. the tuning
voltage. It is a very important parameter for the low-pass filter.
Figure 28 shows a graph of the tuning sensitivity (in MHz/V)
vs. the inductance (nH). It can be seen that as the inductance
increases, the sensitivity decreases. This relationship can be
derived from the previous equation; that is, because the
inductance increased, the change in capacitance from the
varactor has less of an effect on the frequency.
O
EXT
is the center frequency.
is the external inductance.
f
Figure 27. Output Center Frequency vs. External Inductor Value
O
450
400
350
300
250
200
150
100
50
0
=
0
2π
9.3
100
pF
(
0.9
1
200
nH
INDUCTANCE (nH)
+
L
300
EXT
)
400
500
600
Rev. A | Page 20 of 24
ENCODE CLOCK FOR ADC
Analog-to-digital converters (ADCs) require a sampling clock
for their operation. Generally, this is provided by TCXO or VCXOs,
which can be large and expensive. The frequency range is usually
quite limited. An alternative solution is the ADF4360-9, which can
be used to generate a CMOS clock signal suitable for use in all
but the most demanding converter applications.
Figure 29 shows an ADF4360-9 with a VCO frequency of 320 MHz
and a DIVOUT frequency of 80 MHz. Because a 50% duty cycle
is preferred by most sampling clock circuitry, the A/2 mode is
selected. Therefore, A is programmed to 2, giving an overall
divide value of 4. The
that requires an encode clock jitter of 6 ps or less. The ADF4360-9
takes a 10 MHz TCXO frequency and divides this to 1 MHz;
therefore, R = 10 is programmed and N = 320 is programmed
to achieve a VCO frequency of 320 MHz. The resultant 80 MHz
CMOS signal has a jitter of <1.5 ps, which is more than adequate
for the application.
470Ω
10MHz
TCXO
Figure 29. The ADF4360-9 Used as an Encode Clock for an ADC
12
10
21nH
ADF4360-9
GENERATOR
8
6
4
2
0
0
SIGNAL
80MHz
Figure 28. Tuning Sensitivity vs. Inductance
100
21nH
470Ω
AD9215-80
200
LPF
INDUCTANCE (nH)
300
A
is a 10-bit, 80 MSPS ADC
SPI
IN
AD9215-80
ENCODE
CLOCK
400
500
EVALA-SC
HC-ADC-
PC
600
USB