ADF4157_15 Datasheet, PDF (1/24 Pages) Analog Devices – High Resolution 6 GHz Fractional-N Frequency Synthesizer

Data Sheet
High Resolution 6 GHz Fractional-N
Frequency Synthesizer
ADF4157
FEATURES
GENERAL DESCRIPTION
RF bandwidth to 6 GHz
25-bit fixed modulus allows subhertz frequency resolution
2.7 V to 3.3 V power supply
Separate V_P allows extended tuning voltage
Programmable charge pump currents
3-wire serial interface
Digital lock detect
Power-down mode
Pin compatible with the following frequency synthesizers:
ADF4110/ADF4111/ADF4112/ADF4113/
ADF4106/ADF4153/ADF4154/ADF4156
Cycle slip reduction for faster lock times
APPLICATIONS
The ADF4157 is a 6 GHz fractional-N frequency synthesizer with
a 25-bit fixed modulus, allowing subhertz frequency resolution
at 6 GHz. It consists of a low noise digital phase frequency detector
(PFD), a precision charge pump, and a programmable reference
divider. There is a Σ-Δ based fractional interpolator to allow
programmable fractional-N division. The INT and FRAC values
define an overall N divider, N = INT + (FRAC/2²⁵). The ADF4157
features cycle slip reduction circuitry, which leads to faster lock
times without the need for modifications to the loop filter.
Control of all on-chip registers is via a simple 3-wire interface.
The device operates with a power supply ranging from 2.7 V to
3.3 V and can be powered down when not in use.
Satellite communications terminals, radar equipment
Instrumentation equipment
Personal mobile radio (PMR)
Base stations for mobile radio
Wireless handsets
FUNCTIONAL BLOCK DIAGRAM
AV_DD DV_DD V_P
R_SET
ADF4157
REF_IN
MUXOUT
CE
×2
DOUBLER
5-BIT
R COUNTER
÷2
DIVIDER
HIGH Z
OUTPUT
MUX
V_DD
DGND
SD_OUT
V_DD
R_DIV
N_DIV
LOCK
DETECT
THIRD-ORDER
FRACTIONAL
INTERPOLATOR
REFERENCE
+ _PHASE
FREQUENCY
DETECTOR
–
CHARGE
CP
PUMP
CSR
CURRENT
SETTING
RFCP4 RFCP3 RFCP2 RFCP1
N COUNTER
RF_INA
RF_INB
CLK
DATA
LE
32-BIT
DATA
REGISTER
FRACTION MODULUS
REG
2²⁵
INTEGER
REG
AGND
DGND
Figure 1.
CPGND
Rev. D
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