SC7731GPCBdesignguideV101-EN

SC7731GPCBDesignGuideV1.0.1SpreadtrumConfidentialContent.2PMUDesignGuideRFDesignGuideSystemDiagramBaseBandDesignGuideSpreadtrumConfidential.32014-9-15VersionDataAuthorDescriptionV1.0.02014.7.8sandyFirstversionV1.0.12014.9.3sandy•ChangethePMUVBATlayoutrequirementSpreadtrumConfidential.42014-9-15TableofContentsüPackage•Packagesize•Footprint•SignalsdistributionüCommondesignrules•Stackup•Commonrules•Viastype•Fanout•PlacementüHighspeeddesignrules•PDN•DDR•EMMCüRFüPMUüothersSpreadtrumConfidentialPackageSizeInformation(SC7731G).52014-9-15Packageinfo:1.Packagesize:13.3X12.1X0.9mmmax2.Ballpitch:0.4mm3.Balldiameter:0.25mm4.Ballcount:597SpreadtrumConfidentialFootprint.62014-9-15Footprintinfo:1.Balldiameter:0.25mm2.Ballpitch:0.4mm3.Soldermaskopening:0.32mm4.Pastermastopening:0.27mmSpreadtrumConfidentialSignalsdistribution.72014-9-15DDRNANDKEY,IIS,Trace,UARTCSIEMMCDCDCDSISIM&SDUSBRFCTRLRFIQLDOAudioLDOSpreadtrumConfidential.82014-9-15TableofContentsüPackage•Packagesize•Footprint•SignalsdistributionüCommondesignrules•Stackup•Commonrules•Viastype•Fanout•PlacementüHighspeeddesignrules•PDN•DDR•EMMCüRFüPMUüothersSpreadtrumConfidential.92014-9-15PCBLayerstackPCBIfneedtoadjustthethickness,pleasekeepthethicknessofPP,justadjustthethicknessofCORE.SpreadtrumConfidential.102014-9-15PCBLayerstackPCBIfneedtoadjustthethickness,pleasekeepthethicknessofPP,justadjustthethicknessofCORE.SpreadtrumConfidentialCommonDesignRule.112014-9-15InternalchipAlllayersExternalchipUnit:mmSpreadtrumConfidentialVIAtype.122014-9-15Laservia:Drill0.1mmDiameter0.25mmBuriedvia:Drill0.25mmDiameter0.45mmSpreadtrumConfidentialPCBFanout.132014-9-15Thetraceofoutsidetworow/columnballsroutingfromtoplayerPassthreetracesSpreadtrumConfidentialPCBFanout.142014-9-15Mostofthetracesofrow/column3,4,5ballsroutinginlayer2PassfivetracesSpreadtrumConfidential.152014-9-15ReferencePlacementSC7731GLCDTFlashRFAntennaSIMCOFBT+WIFI+FM+GPSLPDDR2USBCameraBATRFSpreadtrumConfidential.162014-9-15TableofContentsüPackage•Packagesize•Footprint•SignalsdistributionüCommondesignrules•Stackup•Commonrules•Viastype•Fanout•PlacementüHighspeeddesignrules•PDN•DDR•EMMCüRFüPMUüothersSpreadtrumConfidentialPDNTheoryIntroducePowerDeliveryNetworkprovidepowerforproperoperationoftheprocessor.Thefrequencyoftheprocessorisupto1GHzevenmorehigh,thecorequantityisfromsinglecoretoquadcores,sothePDNbecomemoreandmorecritical.GenerallythePDNincludeVRM(VoltageRegulationModule),decouplingcapacitors,powerplane(ortrace)andGNDplane..172014-9-15ThepurposeofPDNdesignisminimizetheimpedanceovertheallfrequencyrange，ThetargetimpedancecanbedefinedasVRipple：themaximumallowedvoltagevariationforprocessorImax：themaximumcurrentSpreadtrumConfidentialCapacitorFrquencyCharacteristics.182014-9-15Anon-idealcapacitorcanbemodeledbycombinationsofcapacitance,inductanceandrestistance.Therightfigureistheequivalentcircuit.AtypicalcapacitorfrequencyResponseTheblackcurveistheimpedancecharacteristicsofthecombinationMulticapacitorscombinationfrequencyresponseFrequency[MHz]SpreadtrumConfidentialPDNImpedanceDistributionPCBdesign,decouplingcapacitors,chippackageandchipdesignwilldominatethePDNimpedanceindifferentfrequencyrange:DC-300KHz:thePDNimpedanceisdominatedbypcbandVRM300K-10MHz:thePDNimpedanceisdominatedbypcbanddecouplingcapacitors10M-100MHz:thePDNimpedanceisdominatedbydecouplingcapacitorsandchippackage100M-1GHz:thePDNimpedanceisdominatedbychippackageandchipdesign1G~:thePDNimpedanceisdominatedbychipdesigonly.192014-9-15Note:theimpedancedistributionistheoryvalueonlySpreadtrumConfidentialPDNCriticalPath.202014-9-15ThefollowingfigureisthePNDmodelconsideringtheparasiticparameter.TheCbuckistheDCDCbypasscapacitor,Cdeisthedecouplingcapacitors.ThedashedboxisthePDNcriticalpath,theloopeffectiveinductancedominatethehighfequencyimpedance.Sothedecouplingcapacitorsmustbelocatedasclosetoprocessorpowerpinsaspossible.Itisstrongrecommendedthatthedecouplingcapacitorsareplacedtotheback-sideofthepowerpins.Theloopeffectiveinductanceisproportiontothelooparea.BetterBestBadSpreadtrumConfidentialStackupTheadjacentlayertopowerplaneortracemustbewholeGNDplane,thatcanreducetheeffectiveinducdance,therecommendedstack-upis:.212014-9-15Note:ifneedtomodifythethickness,prefertokeepthedistancebetwenthepowerplaneandGNDplane,thecorethicknesscanbeadjusted.SpreadtrumConfidentialDCDCDesign.222014-9-15LXtracemustbeshortasfaraspossibleTheinductorandcapacitormustbeplacedascloseaspossibleDCDC’sGNDpinsmustusemorethan12blindviasand6buriedviastomainGNDplaneSpreadtrumConfidentialPCBTraceWidthDesign.232014-9-15CalculatetheDCresistanceofthetracecanusingtheformula:ρ：thecopperelecticalresistivityL：tracelengthW：tracewidthH：tracecopperthicknessAcommonruleis1mmwidthtracecorrespondingto1Acurrent.TheVDDARMtracewidthmustnotlessthan2mm,VDDCOREtracewidthmustnotless1.5mm.Thesetracescanberoutedindifferentlayer.HWLR×=rSpreadtrumConfidentialViasConsideration.242014-9-15ØCalculatetheminimumnumberofviasrequiretocarrythecurrent.Typicalblindvia(0.1/0.25mm)andburiedvia(0.25/0.45mm)canbecalculatedaccordingto200mA/viaand40