Fractional-N/Integer-N PLL Synthesizer

Data Sheet

ADF4151

Rev. B

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FEATURES

Fractional-N synthesizer and integer-N synthesizer

RF bandwidth to 3.5 GHz

3.0 V to 3.6 V power supply

1.8 V logic compatibility

voltage (up to 5.5 V) in 3 V systems

Programmable dual-modulus prescaler of 4/5 or 8/9

Programmable RF output phase

3-wire serial interface

Analog and digital lock detect

Switched bandwidth fast lock mode

Cycle slip reduction

APPLICATIONS

Wireless infrastructure (W-CDMA, TD-SCDMA, WiMax, GSM,

PCS, DCS, DECT)

Test equipment

Wireless LANs, CATV equipment

Clock generation

GENERAL DESCRIPTION

The ADF4151 allows implementation of fractional-N or

integer-N phase-locked loop (PLL) frequency synthesizers

if used with an external voltage controlled oscillator (VCO),

loop filter, and external reference frequency.

The ADF4151 is used with external VCO parts and is footprint

and software compatible with the ADF4350. The part 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, FRAC, and MOD registers

define an overall N divider [N = (INT + (FRAC/MOD))]. The

RF output phase is programmable for applications that require

a particular phase relationship between the output and the

reference. The ADF4151 also features cycle slip reduction

circuitry, leading to faster lock times without the need for

modifications to the loop filter.

Control of all the on-chip registers is through a simple 3-wire

interface. The device operates with a power supply ranging

from 3.0 V to 3.6 V that can be powered down when not in use.

The ADF4151 is available in a 5 mm × 5 mm package.

FUNCTIONAL BLOCK DIAGRAM

MUXOUT

LD

SW

CLK

DATA

LE

CE

PHASE

COMPARATOR

CHARGE

PUMP

10-BIT R

COUNTER

÷2

DIVIDER

×2

DOUBLER

FUNCTION

LATCH

DATA REGISTER

INTEGER

REG

N COUNTER

FRACTION

REG

THIRD-ORDER

FRACTIONAL

INTERPOLATOR

MODULUS

REG

MULTIPLEXER

LOCK

DETECT

ADF4151

Figure 1.