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1、 SFF 8431簡介及SFI電氣參數測試 Agenda IntroductionofSFF 8431SFF 8431StandardComplianceTestofSFIEyeDiagramTestbyDSA8200 IntroductionofSFF 8431 BRIEFINTRODUCTIONOFSFF 8431ThespecificationofSFF 8431definestheelectricalinterfacesandtheirtestmethodsbetweentheSFP moduleandhostboardforoperationupto11 1GBd Thehighsp
2、eedelectricalinterfacebetweenthehostandSFP moduleiscalled SFI SFIsimplifiesthemoduleandleverageshostbasedtransmitpre emphasisandhostbasedreceiveequalizationtoovercomePCBandexternalmediaimpairments SFItypicallyoperateswithoneconnectoratthemoduleinterfaceanduptoabout200mmofimprovedFR4materialor150mmof
3、standardFR4 Theelectricalinterfaceisbasedonhighspeed lowvoltageACcoupledlogicwithanominaldifferentialimpedanceof100 TheSFP specificationsincludesmanagement lowspeedsignal highspeedsignal connector definedbySFF 8083 mechanical definedbySFF 8432 andappendicesprovidingparameterandtestboarddefinitions a
4、ndimplementationandmeasurementdescriptions IntroductionofSFF 8431 TheSFP SUPPORTEDSTANDARDS IntroductionofSFF 8431 POWERSPECIFICATIONSOFSFP ThemodulesignalgroundcontactsVeeRandVeeTshouldbeisolatedfrommodulecase AthostpowerupthehostshallsupplyVccTandVccRtothemodulewithin100msofeachother SFP lowspeeds
5、ignalingisbasedonLowVoltageTTL LVTTL operatingwithamodulesupplyof3 3V 5 andwithahostsupplyrangeof2 38to3 46V Toavoidexceedingsystempowersupplylimitsandcoolingcapacity allmodulesatpowerupbydefaultshalloperatewith 1 0W HostssupportingPowerLevelIIoperationmayenableaPowerLevelIImodulethroughthe2 wireint
6、erface PowerLevelIImodulesshallassertthepowerleveldeclarationbitofSFF 8472 Overlongspanssuchasthe40kmEthernetextendedreach ER longwavelengthapplications theSFP transceiversmayrequireadditionalpowerconsumption especiallyatextremeoperatingconditions PowerLevelImodules Upto1 0W PowerLevelIImodules Upto
7、1 5W GENERALREQUIREMENTS IntroductionofSFF 8431 Themaximumpowerlevelisallowedtoexceedtheclassifiedpowerlevelfor500msfollowinghotinsertionorpowerup orPowerLevelIIauthorization howeverthecurrentislimitedtovaluesgivenbythefollowingtable POWERSPECIFICATIONSOFSFP IntroductionofSFF 8431 TheSFP moduleshall
8、meetESDrequirementsgiveninEN61000 4 2 criterionBtestspecificationsuchthatunitsaresubjectedto15kVairdischargesduringoperationand8kVdirectcontactdischargestothecase IntroductionofSFF 8431 HIGHSPEEDELECTRICALSPECIFICATIONSofSFI SFIsignalingisbasedondifferentialhighspeedlowvoltagelogicwithACcouplinginth
9、emodule SFIwasdevelopedwiththeprimarygoaloflowpowerandlowelectromagneticinterference EMI Tosatisfythisrequirementthenominaldifferentialsignallevelsare 500mVp pwithedgespeedcontroltoreduceEMI IntroductionofSFF 8431 PCBLAYOUTRECOMMENDATIONS ThePCBtracesarerecommendedbythespecificationtomeet100 10 diff
10、erentialimpedacewithnominal7 differentialcoupling Itispreferabletohavetheimpedancetolerancebe 5 Routedifferentialpairsatleast8xtheirtrace widthfromothertraces Avoidsharpanglesinrouting chamfercorners Inordertoavoidreflection therecommendedminimumtracelengthrequirementis 1inch inFR4 Whentheremustbevi
11、asonthehigh speeddifferentialsignals the100differentialviasisrecommendedbeused Andstubsduetoviasmustbeavoided ThemaximumSFItracelengthrecommendbythespecificationofSFF 8431 SFF 8431StandardComplianceTestofSFI TESTENVIRONMENTREQUIREMENTSThebandwidthofmeasurementinstrumentshallbe12GHzorabove RequireACc
12、oupledtestequipmentonalltestports AllSFItestequipmentmusthave50ohmsingleendedimpedance Referenceimpedancefordifferentialmeasurementsis100ohm andthereferenceimpedanceforcommonmodemeasurementsis25ohm Hostcompliancetestboardisrequired SFF 8431STANDARDCOMPLIANCETESTofSFI TESTMETHODOLOGYANDMEASUREMENTHOS
13、TCOMPLIANCETESTA 1TestpointHostsystemtransmitterandreceivercompliancearedefinedbytestsinwhichaHostComplianceBoardisinsertedinplaceoftheSFP module ThecompliancepointsareB SFF 8431StandardComplianceTestofSFI A 2Measurementsetup SFF 8431StandardComplianceTestofSFI A 2TESTEQUIPMENT SFF 8431StandardCompl
14、ianceTestofSFI A 3HostTransmitterOutputJitterandEyeMaskSpecificationsatB SFF 8431StandardComplianceTestofSFI 10GSFP CuDIRECTATTACHCABLEComplianceTest 10GSFP CucableassembliesareeffectivelyconstructedoutofapairofSFP moduleswiththeOEcomponentsreplacedwithcoppercabling ThecableassemblyshallincorporateD
15、Cblockingcapacitorswithatleast4 3VratingontheRXsideandwithhighpasspoleofbetween20kHzand100kHz ThedrainwireisconnectedtoVeeTandtoVeeR ThecableshielddirectlyconnectsthemoduleAandBcases B 110GSFP CuDirectAttachConstruction SFF 8431StandardComplianceTestofSFI SFF 8431StandardComplianceTestofSFI B 2SFP D
16、irectAttachCableTestSetup SFF 8431StandardComplianceTestofSFI B 310GSFP CuCableAssemblySpecificationsatB andC OurTestEnvironment Figure1 EyeDiagramTestbyDSA8200 KeyfeaturesofTestInstrumentsDSA8200DigitalSerialAnalyzerDCto65GHzopticalbandwidth DCto70 GHzelectricalbandwidth withupto12 5GHztriggering Bandwidthisdeterminedbythecapabilitiesoftheinstalledmodules CR125AElectricalClockRecoveryinstrument100Mb sto12 5Gb scontinuousdataratecoverage Single endedordifferential50 datainputs outputs DCcoupledd
