2.5G SFP光模块设计参考方案

ReferenceDesign:HFRD-04.0Rev.7:11/08AsofJuly,2008thisreferencedesignboardisnolongeravailable.Gerberfilesandschematicsareavailableuponrequest.REFERENCEDESIGN2.7Gbps,1310nmSmallFormFactorPluggable(SFP)TransceiverMaximIntegratedProductsReferenceDesignHFRD-04.0(Rev.7;11/08)MaximIntegratedProductsPage2of21ReferenceDesign:2.7Gbps,1310nmSFPTransceiverTableofContentsOverview........................................................2ObtainingAdditionalInformation..................2ReferenceDesignDetails...............................3RecommendedOperatingConditions.............5TypicalDesignPerformanceData..................6TransmitterCharacteristicGraphs..................8ReceiverCharacteristicGraphs......................10ApplicationInformation.................................12QuickStart......................................................14PadDescription..............................................15ComponentList(SFPBoard).........................16Schematics(SFPBoard).................................17SFPBoardDimensions...................................18SFPBoardLayout..........................................19SFPLayerProfile...........................................21AdditionalEvaluationMaterials.....................211OverviewHighFrequencyReferenceDesign(HFRD)4.0isacompleteopticaltransceivertargetedfortheSmallFormFactorPluggable(SFP)MultisourceAgreement(MSA)marketandotherhigh-speedopticaltransceiverapplications.Dataratesupto2.7Gbpsareattainablewiththehigh-speedFabryPerotlaser,thehigh-speedMAX3735Adirectmodulationlaserdriver,theMAX3744transimpedanceamplifier(TIA),thehigh-speedPINphotodiodeandtheMAX3748limitingamplifier.Averagepowerandextinctionratioareheldconstantoverthefull–40oCto+85oCtemperaturerangeusingtheAPCloopoftheMAX3735AandtheDallasSemiconductorDS1859dualtemperature-controlleddigitalresistors.TheDS1859providesdigitalmonitorsforbiascurrent,monitordiodecurrent,receivedpower,VCCandtemperature.ThedeviceiscompatiblewithSFF8472digitaldiagnosticrequirementsandhasthecapabilityofperforminginternalcalibrationandmonitorscaling/offsets.TheHFRD-4.0transceiverreducesdesigntimeforSFPandotheropticaltransmittersbyprovidingtheschematics,PCboardlayout,GerberfilesandbillofmaterialsforacompleteSFPtransceiver.Testdataandtypicalperformancefromanassembledboardarealsogiventoaidintheevaluationofthisreferencedesign.1.1Features•SchematicsandBillofMaterialsProvided•GerberPlotFilesAvailable•Multi-Rate(upto2.7Gbps)•Single+3.3VPowerSupply•SFPMultisourceFootprint•DigitalDiagnosticMonitorsandInternalCalibration.•-40oCto+85oCOperatingRange•TemperatureCompensationusingVariableDigitalResistorswithLook-UpTableandDigitalDiagnostics•AssembledSFPtransceiverBoard(RD004-1)andSFPHostBoard(RD003-2)areAvailableforEvaluation2ObtainingAdditionalInformationLimitedquantitiesoftheRD004-1SFPtransceiverboardandRD003-2SFPhostboardareavailable.FormoreinformationaboutthereferencedesignortoobtainanSFPtransceiverand/orhostboardpleaseemailto:(Rev.7;11/08)MaximIntegratedProductsPage3of213ReferenceDesignDetailsTheHFRD-4.0SFPtransceiverreferencedesign(Figure1)isimplementedusingahigh-speedlaserdriver(MAX3735A),adualtemperature-controlledvariableresistor(DS1859)withmonitorsandinternalcalibration,aFabry-Perotlaser(ExceLightSLT2170-LN),ahigh-speedlimitingamplifierwithRSSIoutput(MAX3748),aReceiverOpticalSub-Assembly(theROSAincludesaMAX3744andaPINphotodiode),andanSFPmoduleboard(RD004-1).ThedesignisSFPandSFF8472MSAcompatibleandincorporatesoptionalsafetyfeaturesandinternalcalibration.Thetransmittersectionismulti-ratecompatibleandcanbeoperatedatdataratesfrom155Mbpsto2.7Gbpsusinglongpseudo-randombitstream(PRBS)patterns.Thereceiversectionofthedesignmayalsobeoperatedat155Mbpsto2.7Gbps;however,overloadoftheMAX3744TIAisreducedatdataratesbelow2.5Gbps.Seesection8.7,OperatingatLowerDataRatesforadditionalinformation.3.1TransmitterComponents3.1.1MAX3735ALaserDriverTheMAX3735AisdesignedfordirectmodulationofDC-coupledlaserdiodesatdataratesupto2.7Gbps.Anautomaticpowercontrol(APC)loopisusedtomaintainaveragepowerovertemperature.TheMAX3735Acanmodulatelaserdiodesatamplitudesupto60mAp-p(85mAp-pAC-coupled)andsupplybiascurrentsupto100mA.Typicaledgespeedsare50ps.TheMAX3735AfeaturescurrentmonitorsandsafetyfeaturesincompliancewiththeSFPMSA.ATX_FAULToutputisprovidedtoindicatewhentheAPCloopisunabletomaintaintheaverageopticalpowerorwhenasafetyfaulthasoccurred.ForadditionalinformationseetheMAX3735datasheetavailableonthewebat“direct-to-digital”temperaturesensor,threeexternalvoltagemonitors,andoneinternalvoltagemonitorforVCC.TheDS1859iscompliantwithSFF-8472requirementsandprovidesinternalcalibration.Thedeviceprovidestemperaturecompensationtothebiasandmodulationcurrentsbychangingtheresistanceseenbythecurrent-settingpinsoftheMAX3735A.Thevariableresistors’settingsarestoredinEEPROMmemoryandcanbeaccessed