SFF 8431簡介及SFI電氣參數測試 Agenda IntroductionofSFF 8431SFF 8431StandardComplianceTestofSFIEyeDiagramTestbyDSA8200 IntroductionofSFF 8431 BRIEFINTRODUCTIONOFSFF 8431ThespecificationofSFF 8431definestheelectricalinterfacesandtheirtestmethodsbetweentheSFP moduleandhostboardforoperationupto11 1GBd ThehighspeedelectricalinterfacebetweenthehostandSFP moduleiscalled SFI SFIsimplifiesthemoduleandleverageshostbasedtransmitpre emphasisandhostbasedreceiveequalizationtoovercomePCBandexternalmediaimpairments SFItypicallyoperateswithoneconnectoratthemoduleinterfaceanduptoabout200mmofimprovedFR4materialor150mmofstandardFR4 Theelectricalinterfaceisbasedonhighspeed lowvoltageACcoupledlogicwithanominaldifferentialimpedanceof100 TheSFP specificationsincludesmanagement lowspeedsignal highspeedsignal connector definedbySFF 8083 mechanical definedbySFF 8432 andappendicesprovidingparameterandtestboarddefinitions andimplementationandmeasurementdescriptions IntroductionofSFF 8431 TheSFP SUPPORTEDSTANDARDS IntroductionofSFF 8431 POWERSPECIFICATIONSOFSFP ThemodulesignalgroundcontactsVeeRandVeeTshouldbeisolatedfrommodulecase AthostpowerupthehostshallsupplyVccTandVccRtothemodulewithin100msofeachother SFP lowspeedsignalingisbasedonLowVoltageTTL LVTTL operatingwithamodulesupplyof3 3V 5 andwithahostsupplyrangeof2 38to3 46V Toavoidexceedingsystempowersupplylimitsandcoolingcapacity allmodulesatpowerupbydefaultshalloperatewith 1 0W HostssupportingPowerLevelIIoperationmayenableaPowerLevelIImodulethroughthe2 wireinterface PowerLevelIImodulesshallassertthepowerleveldeclarationbitofSFF 8472 Overlongspanssuchasthe40kmEthernetextendedreach ER longwavelengthapplications theSFP transceiversmayrequireadditionalpowerconsumption especiallyatextremeoperatingconditions PowerLevelImodules Upto1 0W PowerLevelIImodules Upto1 5W GENERALREQUIREMENTS IntroductionofSFF 8431 Themaximumpowerlevelisallowedtoexceedtheclassifiedpowerlevelfor500msfollowinghotinsertionorpowerup orPowerLevelIIauthorization howeverthecurrentislimitedtovaluesgivenbythefollowingtable POWERSPECIFICATIONSOFSFP IntroductionofSFF 8431 TheSFP moduleshallmeetESDrequirementsgiveninEN61000 4 2 criterionBtestspecificationsuchthatunitsaresubjectedto15kVairdischargesduringoperationand8kVdirectcontactdischargestothecase IntroductionofSFF 8431 HIGHSPEEDELECTRICALSPECIFICATIONSofSFI SFIsignalingisbasedondifferentialhighspeedlowvoltagelogicwithACcouplinginthemodule SFIwasdevelopedwiththeprimarygoaloflowpowerandlowelectromagneticinterference EMI Tosatisfythisrequirementthenominaldifferentialsignallevelsare 500mVp pwithedgespeedcontroltoreduceEMI IntroductionofSFF 8431 PCBLAYOUTRECOMMENDATIONS ThePCBtracesarerecommendedbythespecificationtomeet100 10 differentialimpedacewithnominal7 differentialcoupling Itispreferabletohavetheimpedancetolerancebe 5 Routedifferentialpairsatleast8xtheirtrace widthfromothertraces Avoidsharpanglesinrouting chamfercorners Inordertoavoidreflection therecommendedminimumtracelengthrequirementis 1inch inFR4 Whentheremustbeviasonthehigh speeddifferentialsignals the100differentialviasisrecommendedbeused Andstubsduetoviasmustbeavoided ThemaximumSFItracelengthrecommendbythespecificationofSFF 8431 SFF 8431StandardComplianceTestofSFI TESTENVIRONMENTREQUIREMENTSThebandwidthofmeasurementinstrumentshallbe12GHzorabove RequireACcoupledtestequipmentonalltestports AllSFItestequipmentmusthave50ohmsingleendedimpedance Referenceimpedancefordifferentialmeasurementsis100ohm andthereferenceimpedanceforcommonmodemeasurementsis25ohm Hostcompliancetestboardisrequired SFF 8431STANDARDCOMPLIANCETESTofSFI TESTMETHODOLOGYANDMEASUREMENTHOSTCOMPLIANCETESTA 1TestpointHostsystemtransmitterandreceivercompliancearedefinedbytestsinwhichaHostComplianceBoardisinsertedinplaceoftheSFP module ThecompliancepointsareB SFF 8431StandardComplianceTestofSFI A 2Measurementsetup SFF 8431StandardComplianceTestofSFI A 2TESTEQUIPMENT SFF 8431StandardComplianceTestofSFI A 3HostTransmitterOutputJitterandEyeMaskSpecificationsatB SFF 8431StandardComplianceTestofSFI 10GSFP CuDIRECTATTACHCABLEComplianceTest 10GSFP CucableassembliesareeffectivelyconstructedoutofapairofSFP moduleswiththeOEcomponentsreplacedwithcoppercabling ThecableassemblyshallincorporateDCblockingcapacitorswithatleast4 3VratingontheRXsideandwithhighpasspoleofbetween20kHzand100kHz ThedrainwireisconnectedtoVeeTandtoVeeR ThecableshielddirectlyconnectsthemoduleAandBcases B 110GSFP CuDirectAttachConstruction SFF 8431StandardComplianceTestofSFI SFF 8431StandardComplianceTestofSFI B 2SFP DirectAttachCableTestSetup SFF 8431StandardComplianceTestofSFI B 310GSFP CuCableAssemblySpecificationsatB andC OurTestEnvironment Figure1 EyeDiagramTestbyDSA8200 KeyfeaturesofTestInstrumentsDSA8200DigitalSerialAnalyzerDCto65GHzopticalbandwidth DCto70 GHzelectricalbandwidth withupto12 5GHztriggering Bandwidthisdeterminedbythecapabilitiesoftheinstalledmodules CR125AElectricalClockRecoveryinstrument100Mb sto12 5Gb scontinuousdataratecoverage Single endedordifferential50 datainputs outputs DCcoupledd