CLC014AdaptiveCableEqualizerforHigh-SpeedDataRecoveryAugust2003
CLC014
AdaptiveCableEqualizerforHigh-SpeedDataRecovery
GeneralDescription
National’sCLC014adaptivecableequalizerisalow-costmonolithicsolutionforequalizingdatatransmittedovercable(oranymediawithsimilardispersivelosscharacteristics).TheCLC014simplifiesthetaskofhigh-speeddatarecoverywithaone-chipsolutionandaminimalnumberofexternalcomponents.Theequalizerautomaticallyadaptstoequalizeanycablelengthfromzerometerstolengthsthatattenuatethesignalby40dBat200MHz.Thiscorrespondsto300metersofBelden8281or120metersofCategory5UTP(unshieldedtwistedpair).
TheCLC014providessuperiorjitterperformance:180psppfor270Mbpsdatathathaspassedthrough200metersofBelden8281cable.Thisexceptionalperfor-manceprovideswideerrormarginindigitaldatalinks.Theequalizeroperatesonasinglesupplywithapowerconsumptionofonly290mW.Thesmall14-pinSOICpack-ageallowsforhigh-densityplacementofcomponentsformulti-channelapplicationssuchasrouters.Theequalizeroperatesoverawiderangeofdataratesfromlessthan50Mbpstoratesinexcessof650Mbps.
Theequalizerisflexibleinallowingeithersingle-endedordifferentialinputdrive.Itshighcommonmoderejectionpro-videsexcellentimmunitytointerferencefromnoisesources.On-chipquantizedfeedbackeliminatesbaselinewander.Additionalfeaturesincludeacarrierdetectoutputandanoutputmutepinwhich,whentiedtogether,mutetheoutputwhennosignalispresent.Abufferedeyemonitoroutputisprovided,forviewingtheequalizedsignalpriortothecom-parator.DifferentialAECpinsallowtheusertosettheinter-naladaptivelooptimeconstantwithoneexternalcapacitor.Also,theCLC014isinsensitivetothepathologicalpatternsinherentinthevideoindustrystandards.
Features
nnnnnn
AutomaticequalizationofcoaxialandtwistedpaircablesCarrierdetectionandoutputmuteOutputeyemonitor
Singlesupplyoperation:+5Vor−5.2VSingle-endedordifferentialinputLowcost
Applications
nSMPTE259Mserialdigitalinterfaces:NTSC/PAL,4:2:2componentandwidescreen;also540Mbps(4:4:4:4)nSerialdigitalvideoroutinganddistributionnSerialdigitaldataequalizationandreceptionnDatarecoveryequalization:ATM,CADnetworks,medical,settopterminals,industrialvideonetworks
KeySpecifications
nLowjitter:180pspp@270Mbpsthrough200metersofBelden8281coaxialcable
nHighdatarates:<50Mbpsto>650MbpsnExcellentinputreturnloss:19dB@270MHznLowsupplycurrent:58mA
nEqualizesupto300+metersofBelden8281or120metersofCat5UTPcable
TypicalApplication
10005604
©2003NationalSemiconductorCorporationDS100056www.national.com
元器件交易网www.cecb2b.com
CLC014TypicalApplication(Continued)After EqualizationVertical scale: 200mV/divBefore EqualizationVertical scale: 200mV/div270Mbps data through 300m of Belden 8281 coax cable10005602270Mbps data through 300mof Belden 8281 coax cable10005603ConnectionDiagramPinoutSOIC1000560114-PinSOICOrderNumberCLC014AJESeeNSPackageNumberM14Awww.national.com2
元器件交易网www.cecb2b.com
CLC014AbsoluteMaximumRatings
(Note1)
IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheNationalSemiconductorSalesOffice/Distributorsforavailabilityandspecifications.SupplyVoltage(VCC–VEE)MaximumJunctionTemperatureStorageTemperatureRangeLeadTemperature(Soldering4sec.)ESDRating(Note14)θJA14-PinSOIC(AJE)
MTTF(basedonlimitedlifetestdata)
−0.3V,+6.5V
+150˚C
−65˚Cto+150˚C
+260˚C
SeriesInputResistance(InSeriesw/DI&DI)InputCouplingCapacitanceAECCapacitor(ConnectedbetweenAEC+&AEC−)CableInputVoltageSwing(Note4)DO/DOMinimumVoltage(Note15)
100Ω1.0µF
50pFto1µF720to880mVppVCC–1.6V
<500V
95˚C/W
4.8x107hours
RecommendedOperatingConditions
SupplyVoltage(VCC–VEE)OperatingTemperatureRange
4.5Vto5.5V−40˚Cto+85˚C
ElectricalCharacteristics
(VCC=+5V,VEE=0V,signalsourceswing=0.8Vpp(Note4),CAEC=100pF)
Parameter
DYNAMICPERFORMANCEResidualJitter
100metersBelden8281200metersBelden8281300metersBelden8281EqualizationTimeConstant100metersBelden8281200metersBelden8281300metersBelden8281
outputriseandfalltime(20%–80%)outputdutycycledistortionminimumaveragetransitiondensitymaximumaveragedatarateVCCJitterSensitivity27MHz270MHz
VEEJitterSensitivity27MHz270MHz
STATICPERFORMANCE
SupplyCurrent(IncludesOutputCurrent)VAEC=0VVAEC=0.4V
InputandOutputParametersDO/DOoutputcurrentDO/DOoutputvoltageswingDI/DIcommonmodevoltageAECdifferentialvoltage
Belden8281
3
Conditions
Typ+25˚CMin/Max+25˚C
Min/Max−40˚Cto+85˚C
Units
270MbpsPRN(Note5)270MbpsPRN(Note5)270MbpsPRN(Notes3,5)CAEC=100pF(Note6)CAEC=100pF(Note6)CAEC=100pF(Note6)Rcollector=75Ω
1501803501.52.03.2750301/50
250250500___________
400400750___________
pspppspppsppµsµsµspspstrans/nsMbpsns/Vns/Vns/Vns/V
150mBelden8281(Note7)6500.851.900.551.45
(Note3)(Note3)
585310
48/6843/648.7/11.3650/850
__
40/7537/708.0/12600/900
__
mAmAmAmVVmV/meter
www.national.com
Rcollector=75Ω(Note3)
7503.41.5
元器件交易网www.cecb2b.com
CLC014ElectricalCharacteristics
(VCC=+5V,VEEParameter
AEC+/AEC−commonmode
outputeyemonitor(OEM)biaspotentialcarrierdetect(CD)currentoutput-HIGHcarrierdetect(CD)currentoutput-LOWMUTEvoltageinput-HIGHMUTEvoltageinput-LOWMUTEcurrentinput-HIGHMUTEcurrentinput-LOWTIMINGPERFORMANCECDResponseTimecarrierappliedcarrierremovedMUTEresponsetime
MISCELLANEOUSPERFORMANCEinputresistanceinputcapacitance
inputreturnloss@270MHzmaximumcableattenuation
(Continued)
=0V,signalsourceswing=0.8Vpp(Note4),CAEC=100pF)
Conditions
Typ+25˚C3.63.2
CDVOH=4.5VCDVOL=0.5V(Note3)(Note3)
VIH=5V(Note3)VIL=0V(Note3)
−4006001.81.25.00.2
Min/Max+25˚C
____2.00.8
Min/Max−40˚Cto+85˚C
____2.00.8
UnitsVVµAµAVVnAnA
±100±100±500±500
(Note8)(Note9)(Note10)single-ended
single-ended(Note11)Zo=75Ω(Note12)200MHz(Note13)
1.0122.07.31.01940
_______
_______
µsµsnskΩpFdBdB
Note1:“AbsoluteMaximumRatings”arethosevaluesbeyondwhichthesafetyofthedevicecannotbeguaranteed.Theyarenotmeanttoimplythatthedevicesshouldbeoperatedattheselimits.Thetableof“ElectricalCharacteristics”specifiesconditionsofdeviceoperation.
Note2:Min/maxratingsarebasedonproductcharacterizationandsimulation.Individualparametersaretestedasnoted.Outgoingqualitylevelsaredeterminedfromtestedparameters.
Note3:J-level:spec.is100%testedat+25˚C.
Note4:Thesespecificationsassumean800mVppsignalatthecableinput.Levelsaboveandbelow800mVareallowable,butperformancemayvary.Thecablewillattenuatethesignalpriortoenteringtheequalizer.Note5:Peak-to-peakjitterisdefinedas6timesthermsjitter.
Note6:Formoreinformation,see“CLC014Operation”and“DesignGuidelines”.Note7:50%eyeopening.
Note8:TimefromapplicationofavalidsignaltowhentheCDoutputassertshigh.Note9:TimefromtheremovalofavalidsignaltowhentheCDoutputassertslow.Note10:TimefromassertionofMUTEtowhentheoutputresponds.Note11:Deviceonly.Doesnotincludetypicalpcboardparasitics.Note12:Includestypicalpcboardparasitics.
Note13:Thissetsthemaximumcablelengthfortheequalizer.
Note14:Humanbodymodel,1.5kΩinserieswith100pF;basedonlimitedtestdata.Note15:Tomaintainspecifiedperformance,donotreduceDO/DObelowthislevel.
www.national.com4
元器件交易网www.cecb2b.com
CLC014TypicalPerformanceCharacteristicsBefore Equalization:100m of Belden 8281 Coaxial CableAfter Equalization:100m of Belden 8281 Coaxial CableData Rate: 270Mbps Time (1ns/div)10005605Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 270Mbps Time (1ns/div)10005608Before Equalization:200m of Belden 8281 Coaxial CableAfter Equalization:200m of Belden 8281 Coaxial CableData Rate: 270Mbps Time (1ns/div)10005606Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 270Mbps Time (1ns/div)10005609Before Equalization:300m of Belden 8281 Coaxial CableAfter Equalization:300m of Belden 8281 Coaxial CableData Rate: 270Mbps Time (1ns/div)10005607Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 270Mbps Time (1ns/div)100056105www.national.com
元器件交易网www.cecb2b.com
CLC014TypicalPerformanceCharacteristicsBefore Equalization:100m Category 5 UTP at 51.7Mbps(Continued)After Equalization:100m Category 5 UTP at 51.7MbpsData Rate: 51.7Mbps Time (6ns/div)10005611Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 51.7Mbps Time (6ns/div)10005614Before Equalization:100m Category 5 UTP at 155MbpsAfter Equalization:100m Category 5 UTP at 155MbpsData Rate: 155Mbps Time (2ns/div)10005612Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 155Mbps Time (2ns/div)10005615Before Equalization:100m Category 5 UTP at 311MbpsAfter Equalization:100m Category 5 UTP at 311MbpsData Rate: 311Mbps Time (1ns/div)10005613Equalizer Output (200mV/div)Equalizer Input (200mV/div)Data Rate: 311Mbps Time (1ns/div)10005616www.national.com6
元器件交易网www.cecb2b.com
CLC014TypicalPerformanceCharacteristicsMaximum Data Rate* vs. Cable Length (Typical)800(Continued)Jitter vs. Cable Length500400300200100Data Rate: 270Mbps00501001502002503001000561810005617Maximum Data Rate (Mbps)600400200*Max data rate for 50% eye opening.Eye boundary defined as point whereBER = 1 x 10-9.1002003004005000Peak-to-Peak Jitter (ps)Belden 8281 Cable Length (m)Belden 8281 Cable Length (m)Return Loss0Magnitude (5dB/div)DIDI-25-500100M200M300M400M500M10005619Frequency (Hz)7www.national.com
元器件交易网www.cecb2b.com
CLC014PinDefinitions
NameDI,DIDO,DOAEC+,AEC−
Pin#8,913,146,7
Description
Differentialdatainputs.Differentialcollectordataoutputs(ECLcompatible).AECloopfilterpins.Acapacitorconnected
betweenthesepinsgovernstheloopresponsefortheadaptiveequalizationloop.3
Eyemonitoroutput.Theoutputoftheequalizationfilter.
Carrierdetect.(Lowwhennosignalispresent).
OutputMUTE.(Activelow.)Carrierdetectmaybetiedtothispintoinhibittheoutputwhennosignalispresent.
VCCVEE1,2,Positivesupplypins(ground4or+5V).10,11Negativesupplypins(−5.2V
orground).
BLOCKDESCRIPTION
TheCLC014isanadaptiveequalizerthatreconstructsserialdigitaldatareceivedfromtransmissionlinessuchascoaxialcableortwistedpair.Itstransferfunctionapproximatesthereciprocalofthecablelosscharacteristic.TheblockdiagraminFigure2depictsthemainsignalconditioningblocksforequalizingdigitaldataatthereceivingendofacable.TheCLC014receivesbasebanddifferentialorsingle-endeddigi-talsignalsatitsinputsDIandDI.TheEqualizerblockisatwo-stageadaptivefilter.Thisfilteriscapableofequalizingcablelengthsfromzerometerstolengthsthatrequire40dBofboostat200MHz.
TheQuantizedFeedbackComparatorblockreceivesthedifferentialsignalsfromtheequalizerfilterblock.Thisblockincludestwocomparators.Thefirstcomparatorincorporatesaself-biasingDCrestorecircuit.Thisisfollowedbyasecondhigh-speedcomparatorwithoutputmutecapability.Thesec-ondcomparatorreceivesandslicestheDC-restoreddata.ItsoutputsDOandDOaretakenfromthecollectorsoftheoutputtransistors.MUTElatchesDOandDOwhenaTTLlogiclowlevelisapplied.
TheAdaptiveServoControlblockproducesthesignalforcontrollingthefilterblock,andoutputsavoltageproportionaltocablelength.Itreceivesdifferentialsignalsfromtheoutputofthefilterblockandfromthequantized-feedbackcompara-tor(QFBC)todevelopthecontrolsignal.TheservoloopresponseiscontrolledbyanexternalcapacitorplacedacrosstheAEC+andAEC−pins.Itsoutputvoltage,asmeasureddifferentiallyacrossAEC+andAEC−,isroughlyproportionaltothelengthofthetransmissionline.ForBelden8281coaxialcablethisdifferentialvoltageisabout1.5mV/meter.Oncethisvoltageexceeds500mV,noaddi-tionalequalizationisprovided.
TheCarrierDetect(CD)blockmonitorsthesignalpoweroutoftheequalizingfilterandcomparesittoaninternalrefer-encetodetermineifavalidsignalispresent.ACMOShighoutputindicatesthatdataispresent.TheoutputofCDcanbeconnectedtotheMUTEinputtoautomaticallylatchtheoutputs(DOandDO),preventingrandomtransitionswhennodataispresent.
TheOutputEyeMonitor(OEM)providesasingle-endedbufferedoutputforobservingtheequalizedeyepattern.TheOEMoutputisalowimpedancehigh-speedvoltagedrivercapableofdrivinganAC-coupled100Ωload.
OEM
CDMUTE512
Operation
TheCLC014AdaptiveCableEqualizerprovidesacompletesolutionforequalizinghigh-bit-ratedigitaldatatransmittedoverlongtransmissionlines.Thefollowingsectionsfurnishdesignandapplicationinformationtoassistincompletingasuccessfuldesign:
•BlockdiagramexplanationoftheCLC014
•Recommendedstandardinputandoutputinterfacecon-nections
•CommonapplicationsfortheCLC014
•Measurement,PClayout,andcableemulationboxesForapplicationsassistanceintheU.S.,call800-272-9959tocontactatechnicalstaffmember.
10005620
FIGURE1.CLC014EqualizerApplicationCircuit
www.national.com8
元器件交易网www.cecb2b.com
CLC014Operation
(Continued)
DIFFERENTIALINPUTINTERFACE:TwistedPairArecommendeddifferentialinputinterfaceisshowninFig-ure4.Propervoltagelevelsmustbefurnishedtotheinputpinsandthepropercableterminatingimpedancemustbeprovided.ForCategory5UTPthisisapproximately100Ω.Figure4showsageneralizednetworkwhichmaybeusedtoreceivedataoveratwistedpair.ResistorsR1andR2providetheproperterminatingimpedanceandsignalleveladjust-ment.TheblockingcapacitorsprovideACcouplingoftheattenuatedsignallevels.TheplotsintheTypicalPerfor-manceCharacteristicssectiondemonstratevariousequal-izeddataratesusingCategory5UTPat100meterlengths.Afullschematicofarecommendeddriverandreceivercir-cuitfor100ΩCategory5UTPisprovidedintheTypicalApplicationssectionwithfurtherexplanation.
10005621
FIGURE2.CLC014BlockDiagram
DEVICETESTING
PerformanceorcompliancytestingoftheCLC014withCableClonesisnotallowed.Useofthesedevicesiscon-trarytotheproduct’sspecificationsandtestprocedures.Testingforproductspecificationsorperformanceusingcableclonesisinvalidsincecablecloneshaveadifferentfre-quencyresponsethantheactualcable.Testingwithfulllengthcablesamplesisrecommended.
10005624
FIGURE4.TwistedPairInputInterface
InputInterfacing
TheCLC014acceptseitherdifferentialorsingle-endedinputvoltagespecifiedinStaticPerformance.Thefollowingsec-tionsshowseveralsuggestionsforinterfacesfortheinputsandoutputsoftheCLC014.
SINGLE-ENDEDINPUTINTERFACE:75ΩCoaxialCableTheinputisconnectedsingle-endedtoeitherDIorDIasshowninFigure3.Balancingunusedinputshelpstolessentheeffectsofnoise.Usetheequivalentterminationof37.5Ωtobalancetheinputimpedanceseenbyeachpin.Italsohelpstoterminategroundsatacommonpoint.ResistorsRxandRyarerecommendedforoptimumperformance.Theequalizerinputsareself-biasing.SignalsshouldbeACcoupledtotheinputsasshowninFigure3.
OutputInterfacing
TheoutputsDOandDOproduceECLlogiclevelswhentherecommendedoutputterminationnetworksareused.TheDOandDOpinsarenotcomplementaryemittercoupledlogicoutputs.Instead,theoutputsaretakenoffofthecol-lectorsofthetransistors.Therefore,caremustbetakentomeettheinterfacethresholdlevelsrequiredbyECLfamilies.RecommendedinterfacesforstandardECLfamiliesareshowninthefollowingcircuits.
DIFFERENTIALLOAD-TERMINATEDOUTPUTINTERFACE
Figure5showsarecommendedcircuitforimplementingadifferentialoutputthatisterminatedattheload.Adiodeor75Ωresistorprovidesavoltagedropfromthepositivesupply(+5VforPECLorGroundforECLoperation)toestablishproperECLlevels.Theresistorsterminatethecabletothecharacteristicimpedance.Theoutputvoltageswingisdeter-minedbytheCLC014outputcurrent(10mA)timestheterminationresistor.ForthecircuitinFigure5,thenominaloutputvoltageswingis750mV.
10005622
FIGURE3.Single-Ended75ΩCableInputInterface
9www.national.com
元器件交易网www.cecb2b.com
CLC014OutputInterfacing
(Continued)
10005627
FIGURE7.AlternativeLoadTerminated
OutputInterface
10005625
FIGURE5.DifferentialLoadTerminated
OutputInterface
DIFFERENTIALSOURCE-TERMINATEDOUTPUTINTERFACE
Figure6issimilartoFigure5exceptthattheterminationisprovidedatthesource.Thisconfigurationmayalsobeusedforsingle-endedapplications.However,theunusedoutputmuststillbeterminatedasshown.
DesignGuidelines
SELECTINGTHEAUTOMATICEQUALIZERCAPACITORTheAECcapacitorsetsthelooptimeconstantτfortheequalizer’sadaptiveloopresponsetime.Thefollowingfor-mulaisusedtosetthelooptimeconstant:
τ=R•CAEC•10−6Risaconversionfactorthatissetbyinternalequalizerparametersandcablelength.ForBelden8281coaxialcable,theRvaluesare(τ=µs,CAECinpF):
CableLength100meters200meters300meters
RValue(Ohms)150002000032000
Forexample,aCAECvalueof100pFresultsinanadaptivelooptimeconstantof2µsat200metersofcable.CONNECTIONANDOPERATIONOFCDANDMUTECarrierDetect(CD)isaCMOSoutputthatindicatesthepresenceofequalizeddatafromthefilter.ThisCDoutputcanbeconnectedtoMUTEtosuspendchangesinthedataoutputsDOandDO,ifnovalidsignalexists.Thissimpleconfigurationpreventsrandomoutputtransitionsduetonoise.ForsparsetransitionpatternsitisrecommendedthatacapacitorbeconnectedtoCDasshowninFigure1.
Addacapacitortopin5toslowtheresponsetimeofCarrierDetectwhenCarrierDetectisconnectedtoMUTE.Thecapacitorreducessensitivitytopathologicalpatterns.Patho-logicalpatternsaredefinedassparsedatasequenceswithfewtransitions.
OUTPUTEYEMONITOROEMCONNECTIONS
TheOEMisahigh-speed,bufferedoutputformonitoringtheequalizedeyepatternpriortotheoutputcomparator.ItsoutputisdesignedtodriveanAC-coupled50Ωcoaxialcablewithaseries50Ωbackmatchresistor.Thecableshouldbeterminatedwith50Ωattheoscilloscope.Figure1showsaschematicwithatypicalconnection.
10005626
FIGURE6.DifferentialSourceTerminated
OutputInterface
TERMINATINGPHYSICALLYSEPARATEDOUTPUTSWhenthetwooutputsmustberoutedtophysicallyseparatelocations,thecircuitinFigure6maybeapplied.Alterna-tively,ifloadterminationisdesired,thecircuitinFigure7maybeused.Theresistivedividernetworkprovides75ΩterminationandestablishesproperECLlevels.Thiscircuitconsumesslightlymorepowerthanthepreviouscircuits.
www.national.com10
元器件交易网www.cecb2b.com
CLC014DesignGuidelines
MINIMUMDATATRANSITIONS
(Continued)
TheCLC014specifiesaminimumtransitionrate.FortheCLC014thissetstheminimumdataratefortransmittingdatathroughanycablemedium.TheCLC014minimumaveragetransitiondensityisfoundintheElectricalCharacteristicssectionofthedatasheet.
POWERSUPPLYOPERATIONANDTHERMALCONSIDERATIONS
TheCLC014operatesfromeither+5Vor−5.2Vsinglesup-plies.RefertoFigure1whenoperatingthepartfrom+5V.Whenoperatingwitha−5.2Vsupply,theVEEpinsshouldbebypassedtoground.Theevaluationboardandassociatedliteratureprovideforoperationfromeithersupply.
Maximumpowerdissipationoccursatminimumcablelength.Underthatcondition,ICC=58mA.Totalpowerdissipated:
PT=(58mA)(5V)=290mW
Powerintheload:
PL=(0.7V)(11mA)+(37.5)(11mA)2=12mWMaximumpowerdissipatedonthedie:PDMAX=PT–PL=278mWJunctionTemperature=
(θJA)(278mW)+TA=TA+26˚C
11www.national.com
元器件交易网www.cecb2b.com
CLC014LayoutandMeasurement
TheprintedcircuitboardlayoutfortheCLC014requiresproperhigh-speedlayouttoachievetheperformancespeci-ficationsfoundinthedatasheet.Thefollowinglistcontainsafewrulestofollow:
1.Useagroundplane.2.
Decouplepowerpinswith0.1µFcapacitorsplaced≤0.1”(3mm)fromthepowerpins.
3.DesigntransmissionstriplinesfromtheCLC014’sinput
andoutputpinstotheboardconnectors.4.Routeoutputsawayfrominputs.5.
Keepgroundplane≥0.025”(0.06mm)awayfromtheinputandoutputpads.
Figure8showsablocklevelmeasurementdiagram,whileFigure15ondepictsadetailedschematic.Apseudo-randompatterngeneratorwithlowoutputjitterwasusedtoprovideaNRZIpatterntocreatetheeyediagramsshownintheTypi-calPerformanceCharacteristicssection.
Sincemostpatterngeneratorshavea50Ωoutputimped-ance,atranslationcanbeaccomplishedusingaCLC006CableDriverasanimpedancetransformer.Awideband-widthoscilloscopeisneededtoobservethehighdatarateeyepattern.Whenmonitoringasingleoutputthatistermi-natedatboththeequalizeroutputandtheoscilloscope,theeffectiveoutputloadis37.5Ω.Consequently,thesignalswingishalfthatobservedforasingle-ended75Ωtermination.
10005628
FIGURE8.TypicalMeasurementBlock
Troubleshootingwithscopeprobescanaffecttheequaliza-tion.Forhighdatarates,usealowcapacitanceprobewithlessthan2pFprobecapacitance.EvaluationboardsandliteratureareavailableforquickprototypingandevaluationoftheCLC014AdaptiveCableEqualizer.TheCLC014con-tainsCMOSdevicesandoperatorsshouldusegroundingstrapswhenhandlingtheparts.
Figure9showstheCLC014’sinternalpowersupplyrouting.BypassVCC(pin4)by:
•Monolithiccapacitorofabout0.1µFplacedlessthan0.1”(3mm)fromthepin
•Tantalumcapacitorofabout6.8µFforlargecurrentsignalswingsplacedascloseasconvenienttotheCLC014
10005629
FIGURE9.PowerPackageRoutingFixture
www.national.com12
元器件交易网www.cecb2b.com
CLC014LayoutandMeasurement
(Continued)
CABLEEMULATIONBOXES
Somecableemulationboxeswillnotmimiccablescorrectly.WhenevaluatingtheCLC014,itisstronglyrecommendedthatactualcablebeusedtodeterminethevariousperfor-manceparameters.
TominimizeringingattheCLC014’sinputs,placea100Ωresistorinserieswiththeinput.Thisresistorreducesinduc-tanceeffects.
Severallayouttechniquescanimprovehighspeedperfor-mance:
•Keepinput,outputandAECtraceswellseparated•Usebalancedinputtermination’s
TypicalApplications
COAXIALCABLERECEIVER(Page1)
TheCLC014equalizerapplicationshownonpage1willequalizeavarietyofcoaxialcablesuptolengthsthatattenu-atethesignalby40dBat200MHz.TheapplicationshowstheproperconnectionforasinglecabledrivenwithaCLC006driver.CarrierDetect(CD)isconnectedtoMUTEtolatchoutputsDOandDOintheabsenceofaninputsignaltotheequalizer.
RefertotheCLC014’sevaluationboardlayoutforadditionalsuggestions.
Nationalcansupplymostofthemajorcomponentsrequiredtodesignatransmissionlinerepeater.Figure11showsatypicalrepeaterdesignusingtheCLC006,CLC014,andtheCLC016.Thedesignfunctionssupportedbyeachchipare:CLC006:Cableconnectionchip
Boostsdrivefortransmissiontonextrepeaterorfinaldestinations
CLC014:Receiveserializeddigitaldatafromincoming
transmissionlines
Equalizestheincomingdata
CLC016:Retimestheequalizeddata(improvingjitter)TheCLC016isamulti-ratedataretimingPLL.Thecircuit(Figure11)willworkatupto4differentdatarateswithnoadditionalcomponentsormanualtuning.
•AvoidroutingtracesclosetotheCLC014’sinputtrace•Maintaincommonreturnpointsforcomponents•Useguardtraces
TheinputlinesoftheCLC014usea100Ωseriesresistorsattheinputpins.Thisdecreasestheinductiveeffectsinternaltotheparttoreduceringingonfastriseandfalltimes.RefertotheevaluationboardlayoutforfurthersuggestionsonlayoutfortheCLC014AdaptiveEqualizer.
EQUALIZATIONCURVE
TheCLC014AdaptiveCableEqualizerhasamaximumequalizationresponseasshowninFigure10.Thisresponsemaybeobtainedbyforcing>0.5VdifferentiallyattheAECpins.
Magnitude (5dB/div)10k100k1M10M100M1G10005630
Frequency (Hz)
FIGURE10.MaximumEqualizationResponse
13www.national.com
元器件交易网www.cecb2b.com
CLC014TypicalApplications
(Continued)
10005631
FIGURE11.TypicalRepeaterDesign
DIGITALVIDEO(SDV)ROUTERS
TheCLC014providesperformancethatcomplieswiththeSMPTE259Mstandardforserialdigitalvideo(SDV)trans-missionovercoaxialcable.OnecommonapplicationisinSDVrouters,whichprovideaswitchingmatrixforconnectingvideosourceequipment(e.g.,cameras)todestinationequip-ment(e.g.,videotaperecorders,monitors,etc.).
Figure12showsatypicalconfigurationforanSDVrouter,includingequalizers,acrosspointswitch,dataretimers,andcabledrivers.TheCLC014isusedinitsstandardconfigu-rationinthisapplication,andautomaticallyequalizescablelengthsfromzerometerstogreaterthan300metersat360MHz(seeplotsinTypicalPerformanceCharacteris-ticssection).Theequalizedoutputsareconnectedtothedifferentialinputsofthecrosspointswitch.TheCLC016DataRetimerreceivesthedatafromthecrosspointandperformstheclockanddatarecoveryfunctions,furtherreducingjitter.Finally,theretimeddataisdrivenintothecoaxialcablebyaCLC006CableDriver(withtwoamplitude-adjustableout-puts)oraCLC007CableDriver(withfouroutputs).
10005632
FIGURE12.VideoRoutingBlockDiagram
TWISTEDPAIRDRIVER
Alow-costmediumfortransmittingdataistwistedpair.Cat-egory5UTPhasanattenuationcharacteristicsimilartoBelden8281coaxialcablebutscaledinlength:120metersofCategory5UTPisroughlyequivalentto300metersofBelden8281cable.Whenproperlyimplemented,theCLC014willequalizedataratesupto625MbpsoverCat-egory5UTP.Themaximumdataratedependsuponthecablelength.AplotofMaximumDataRatevsCableLengthisfoundintheTypicalPerformanceCharacteristicssec-tionforBelden8281,andcanbescaledasstatedabovetoestimatemaximumcablelengthsanddataratesforUTP.
www.national.com14
元器件交易网www.cecb2b.com
CLC014TypicalApplications
(Continued)
Category5UTPhasacharacteristicimpedanceofapproxi-mately100Ω.TheCLC006inFigure13isusedtodrivethetwistedpairAC-coupledwithaseries0.1µFcapacitoranda50Ωresistorineachdifferentialoutput.TheCLC014Adap-tiveEqualizerrequires800mVppfromthetransmitsideofthecable.AvoltagedividerisnecessarytoscalethevoltagetotherequiredlevelattheinputoftheCLC014.Thisresistornetworkalsoprovidesthecorrectimpedancematchfortwistedpair.
ForCategory5UTP,theapproximateAECvoltageperlengthis3.75mV/m(seeBlockDescription).TheCLC006providesatrimadjustforfinetuningtheoutputsignalwiththeresistorR.RefertotheCLC006/007datasheetfortuningdirections.
10005634
10005633
FIGURE13.TwistedPairEqualization
FIGURE14.BeforeandAfterEqualizationat622Mbps
Through50MetersofCategory5UTP
10005635
FIGURE15.TypicalMeasurementSetup
15www.national.com
元器件交易网www.cecb2b.com
CLC014EvaluationBoard
EvaluationboardsareavailableforanominalchargethatdemonstratethebasicoperationoftheSDI/SDV/SDHde-vices.TheevaluationboardscanbeorderedthroughNation-al’sDistributors.Suppliesarelimited,pleasecheckforcur-rentavailability.
TheSD014EVKevaluationkitfortheCLC014,AdaptiveCableEqualizerforHigh-SpeedDataRecovery,providesanoperatingenvironmentinwhichthecableequalizercanbeevaluatedbysystem/hardwaredesigners.TheevaluationboardhasalltheneededcircuitryandconnectorsforeasyconnectionandcheckoutofthedevicecircuitoptionsasdiscussedintheCLC014datasheet.Aschematic,partslistandpictorialdrawingareprovidedwiththeboard.
FromtheWWW,thefollowinginformationmaybeviewed/downloadedformostevaluationboards:www.national.com/appinfo/interface
•DeviceDatasheetand/orEVKUserManual
••••ViewViewViewViewapictureoftheEVKtheEVKSchematic
thetopassemblydrawingandBOMthebottomassemblydrawingandBOM
PCBLAYOUT
TheCLC014requiresproperhigh-speedlayouttechniquestoobtainbestresults.AfewrecommendedlayoutrulestofollowforbestresultswhenusingtheCLC014AdaptiveCableEqualizerare:1.2.
Useagroundplane.
Decouplepowerpinswith0.01µFcapacitorsplaced≤0.1”(3mm)fromthepowerpins.
3.Designtransmissionlinestotheinputsandoutputs.4.Routeoutputsawayfrominputs.5.
Removegroundplane≥0.025”(0.06mm)fromtheinputandoutputpads.
www.national.com16
元器件交易网www.cecb2b.com
CLC014AdaptiveCableEqualizerforHigh-SpeedDataRecoveryPhysicalDimensions
unlessotherwisenoted
inches(millimeters)
14-PinSOIC
OrderNumberCLC014AJENSPackageNumberM14A
LIFESUPPORTPOLICY
NATIONAL’SPRODUCTSARENOTAUTHORIZEDFORUSEASCRITICALCOMPONENTSINLIFESUPPORTDEVICESORSYSTEMSWITHOUTTHEEXPRESSWRITTENAPPROVALOFTHEPRESIDENTANDGENERALCOUNSELOFNATIONALSEMICONDUCTORCORPORATION.Asusedherein:1.Lifesupportdevicesorsystemsaredevicesorsystemswhich,(a)areintendedforsurgicalimplantintothebody,or(b)supportorsustainlife,andwhosefailuretoperformwhenproperlyusedinaccordancewithinstructionsforuseprovidedinthelabeling,canbereasonablyexpectedtoresultinasignificantinjurytotheuser.
NationalSemiconductorAmericasCustomerSupportCenter
Email:new.feedback@nsc.comTel:1-800-272-9959
www.national.com
NationalSemiconductor
EuropeCustomerSupportCenter
Fax:+49(0)180-5308586Email:europe.support@nsc.com
DeutschTel:+49(0)6995086208EnglishTel:+44(0)8702402171FrançaisTel:+33(0)141918790
2.Acriticalcomponentisanycomponentofalifesupportdeviceorsystemwhosefailuretoperformcanbereasonablyexpectedtocausethefailureofthelifesupportdeviceorsystem,ortoaffectitssafetyoreffectiveness.
NationalSemiconductorAsiaPacificCustomerSupportCenter
Email:ap.support@nsc.com
NationalSemiconductor
JapanCustomerSupportCenterFax:81-3-5639-7507
Email:jpn.feedback@nsc.comTel:81-3-5639-7560
Nationaldoesnotassumeanyresponsibilityforuseofanycircuitrydescribed,nocircuitpatentlicensesareimpliedandNationalreservestherightatanytimewithoutnoticetochangesaidcircuitryandspecifications.
因篇幅问题不能全部显示，请点此查看更多更全内容