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VddRF5

Phase

Comp

FinIF

Charge

Pump

CPoutIF

Ftest/LD

MUX

Ftest/LD

IF

LD

Phase

Comp

8/9

or

16/17

Prescaler

B Counter

IF N Divider

A Counter

FLoutRF

VddIF2

VddIF1

RFN Divider

GND

GND

GND

FinRF

FinRF*

8/9/12/13

or

16/17/20/21

Prescaler

C Counter

6'

Compensation

A Counter

B Counter

RF N Divider

ENOSC

OSCout

OSCin

VddRF4

VddRF3

VddRF2

VddRF1

IF R

Divider

RF R

Divider

1X / 2X

RF LD

Charge

Pump

CPoutRF

RF Fastlock

MICROWIRE

Interface

CLK

LE

DATA

CE

Product

Folder

Sample &

Buy

Technical

Documents

Tools &

Software

Support &

Community

LMX2485

,

LMX2485E

SNAS236G–OCTOBER2005–REVISEDJANUARY2016

LMX2485x3-GHzDelta-SigmaLow-PowerDualPLLatinum™FrequencySynthesizer

1Features3Description

TheLMX2485deviceisalowpower,high

1

•QuadrupleModulusPrescalerforLowerDivides

performancedelta-sigmafractional-NPLLwithan

–RFPLL:8/9/12/13or16/17/20/21

auxiliaryinteger-NPLL.Thedeviceisfabricated

–IFPLL:8/9or16/17

usingTexasInstruments'advancedprocess.

•AdvancedDelta-SigmaFractionalCompensation

Withdelta-sigmaarchitecture,fractionalspursat

–12-Bitor22-BitSelectableFractionalModulus

loweroffsetfrequenciesarepushedtohigher

frequenciesoutsidetheloopbandwidth.Theabilityto

–Upto4thOrderProgrammableDelta-Sigma

pushcloseinspurandphasenoiseenergytohigher

Modulator

frequenciesisadirectfunctionofthemodulator

•FeaturesforImprovedLockTime

order.Unlikeanalogcompensation,thedigital

–Fastlock/CycleSlipReductionWithIntegrated

feedbacktechniqueusedintheLMX2485ishighly

resistanttochangesintemperatureandvariationsin

Time-OutCounterWhichRequiresOnlya

waferprocessing.TheLMX2485delta-sigma

Single-WordWrite

modulatorisprogrammableuptofourthorder,which

•WideOperatingRange

allowsthedesignertoselecttheoptimummodulator

–LMX2485RFPLL:500MHzto3.0GHz

ordertofitthephasenoise,spur,andlocktime

requirementsofthesystem.

–LMX2485ERFPLL:50MHzto3.0GHz

•UsefulFeatures

SerialdataforprogrammingtheLMX2485is

transferredthroughathree-line,high-speed(20-MHz)

–DigitalLockDetectOutput

MICROWIREinterface.TheLMX2485offersfine

–HardwareandSoftwarePower-DownControl

frequencyresolution,lowspurs,fastprogramming

–On-ChipInputFrequencyDoubler.

speed,andasingle-wordwritetochangethe

frequency.Thismakesitidealfordirectdigital

–RFPhaseDetectorFrequencyupto50MHz

modulationapplications,wheretheN-counteris

–2.5to3.6VOperationWithI

CC

=5.0mA

directlymodulatedwithinformation.TheLMX2485is

availableina24-lead4.0×4.0×0.8mmWQFN

2Applications

package.

•CellularPhonesandBaseStations

DeviceInformation

(1)

•DirectDigitalModulationApplications

PARTNUMBERRFPLLFrequencyIFPLLFrequency

•SatelliteandCableTVTuners

LMX2485E50-3000MHz75-800MHz

•WLANStandards

LMX2485500-3000MHz75-800MHz

(1)Forallavailablepackages,seetheorderableaddendumat

theendofthedatasheet.

FunctionalBlockDiagram

1

AnIMPORTANTNOTICEattheendofthisdatasheetaddressesavailability,warranty,changes,useinsafety-criticalapplications,

intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

Produktspecifikationer