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Dual RF PLL Frequency Synthesizers
ADF4206/ADF4207/ADF4208
GENERAL DESCRIPTION
FEATURES
The ADF4206 family of dual frequency synthesizers can be
used to implement local oscillators in the upconversion and
downconversion sections of wireless receivers and transmitters.
Each synthesizer consists of a low-noise digital PFD (Phase
Frequency Detector), a precision charge pump, a programmable
reference divider, programmable A and B counters and a dual-
modulus prescaler (P/P + 1). The A (6-bit) and B (11-bit)
counters, in conjunction with the dual modulus prescaler (P/P + 1),
implement an N divider (N = BP + A). In addition, the 14-bit
reference counter (R Counter), allows selectable REFIN frequen-
cies at the PFD input. The on-chip oscillator circuitry allows
the reference input to be derived from crystal oscillators.
ADF4206: 550 MHz/550 MHz
ADF4207: 1.1 GHz/1.1 GHz
ADF4208: 2.0 GHz/1.1 GHz
2.7 V to 5.5 V Power Supply
Selectable Charge Pump Supply (VP) Allows Extended
Tuning Voltage in 3 V Systems
Selectable Charge Pump Currents
On-Chip Oscillator Circuit
Selectable Dual Modulus Prescaler
RF2: 32/33 or 64/65
RF1: 32/33 or 64/65
3-Wire Serial Interface
Power-Down Mode
A complete PLL (Phase-Locked Loop) can be implemented if
the synthesizers are used with an external loop filter and VCOs
(Voltage Controlled Oscillators).
APPLICATIONS
Wireless Handsets (GSM, PCS, DCS, CDMA, WCDMA)
Base Stations for Wireless Radio (GSM, PCS, DCS,
CDMA, WCDMA)
Wireless LANS
Communications Test Equipment
CATV Equipment
Control of all the on-chip registers is via a simple 3-wire interface.
The devices operate with a power supply ranging from 2.7 V
to 5.5 V and can be powered down when not in use.
FUNCTIONAL BLOCK DIAGRAM
V
1
V
2
V 1
V 2
P
DD
DD
P
N = BP + A
ADF4206/ADF4207/ADF4208
11-BIT RF2
B-COUNTER
PHASE
COMPARATOR
RF2
A
B
IN
RF2
PRESCALER
RF2
CHARGE
PUMP
IN
CP
RF2
6-BIT RF2
A-COUNTER
RF2
LOCK
DETECT
OSC
IN
OSCILLATOR
OSC
OUT
14-BIT RF2
R-COUNTER
OUTPUT
MUX
MUXOUT
CLOCK
DATA
LE
22-BIT
DATA
REGISTER
SDOUT
RF1
14-BIT RF1
R-COUNTER
LOCK
DETECT
N = BP + A
CHARGE
PUMP
CP
RF1
11-BIT RF1
B-COUNTER
PHASE
COMPARATOR
RF1
A
B
IN
RF1
PRESCALER
RF1
IN
6-BIT RF1
A-COUNTER
AGND
RF1
DGND
RF2
AGND
RF2
DGND
RF1
REV. 0
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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© Analog Devices, Inc., 2001