ADF4206BRU Analog Devices Inc, ADF4206BRU Datasheet - Page 20

• Manufacturer Part Number: ADF4206BRU
• Description: IC PLL FREQ SYNTHESIZER 16-TSSOP
• Manufacturer: Analog Devices Inc
• Type: Clock/Frequency Synthesizer (RF)r

Specifications of ADF4206BRU

• Rohs Status: RoHS non-compliant
• Pll: Yes
• Input: CMOS
• Output: Clock
• Number Of Circuits: 1
• Ratio - Input:output: 3:1
• Differential - Input:output: Yes/No
• Frequency - Max: 550MHz
• Divider/multiplier: No/No
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TSSOP
• Frequency-max: 550MHz

ADF4206/ADF4208
APPLICATIONS SECTION
LOCAL OSCILLATOR FOR GSM HANDSET
RECEIVER
Figure 33 shows the ADF4208 used in a classic superheterodyne
receiver to provide the required local oscillators (LOs).
In this circuit, the reference input signal is applied to the circuit
at OSC
a low cost solution. For better performance over temperature, a
TCXO (temperature controlled crystal oscillator) can be used
instead.
IN
100pF
and is generated by a 10 MHz crystal oscillator. This is
18Ω
18Ω
IF
OUT
DECOUPLING CAPACITORS (22µF/10pF) ON V
THE ADF4208, AND ON V
OMITTED FROM THE DIAGRAM TO AID CLARITY.
18Ω
100pF
VCO190-125T
51Ω
100pF
V
CC
CC
1.3nF
OF THE VCOs HAVE BEEN
30pF
30pF
Figure 32. GSM Handset Receiver Local Oscillator Using the ADF4208
2.7kΩ
3.3kΩ
13nF
DD
10MHz
, V
P
620pF
18kΩ
OF
CP
V
RF2
OSC
OSC
Rev. A | Page 20 of 24
V
P
P
2
RF2
IN
IN
OUT
ADF4208
V
V
DD
DD
2 V
DD
To have a channel spacing of 200 kHz (the GSM standard),
the reference input must be divided by 50 using the on-chip
reference counter.
The RF output frequency range is 1050 MHz to 1086 MHz. Loop
filter component values are chosen so that the loop bandwidth is
20 kHz. The synthesizer is set up for a charge pump current of
4.375 mA and the VCO sensitivity is 15.6 MHz/V.
The IF output is fixed at 125 MHz. The IF loop bandwidth is
chosen to be 20 kHz with a channel spacing of 200 kHz. Loop
filter component values are chosen accordingly.
1
MUXOUT
CP
DATA
RF1
CLK
V
RF1
V
LE
P
P
IN
1
LOCK DETECT
V
VCO190-1068U
CC
100pF
100pF 18Ω
51Ω
100pF
RF
OUT
18Ω
18Ω