sonnet signal integrity in multilayer boards外语英文电子书

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1、SignalIntegrityinMultilayerBoardsSimulationofaModelImportedfromCadenceAllegro®Dr.JamesR.WillhiteImportModelsfromCadenceAllegro®Multilayerdigitalboardsarecomplexstructurestolayoutoftenhaving100’sor1000’sofnets.Astheclockrateshaveincreasedthevarioussignallinesnowmustbedesignedtoincludecouplin

2、gandothermicrowave-likeeffectswhichwerepreviouslyignored.MicrowaveStudiocanimportmodelsfromCadenceAllegroandthesignallinesanalyzedforeffectsinfluencingsignalintegrityto20GHzandbeyond.Thesehigherfrequenciesarerequiredforthenewerapplications.22LayerBoard(Multi-channel10GXFP)ImportedfromCadenc

3、eAllegrobyJimAntonellisofSandburstCorporationandshownwiththeirpermission.2SonnetSoftware,Inc.(315)453-3096mwssupport@sonnetsoftware.comImportBoards,Nets,orRegionsCompleteboarddesignscanbequitelargemodelsandoftenyouneedtostudySIeffectsinonlyalimitednumberofthenets.UsingtheAllegrointerfacetoM

4、WSyoucanchosetobringintheentiredesign,onlycertainregions,oronlycertainnets.Ifyouchosetoimportaregionoftheboardthiscanbetheareainsideageneralpolygon.Ifyouimportselectednets,youcanbringinstructureswithinasetradius.ForthisstudydonewithSandburst,onlyselectednetswereexportedfromtheentireboarddes

5、ign:two,balancedlinepairswithviastoalowerlayerintheboard.Thegoalisastudyofsignalintegrityforthesedifferentiallinepairsinanunpopulatedboard.3SonnetSoftware,Inc.(315)453-3096mwssupport@sonnetsoftware.comViaDownA22-LayerBoardThelinesforeachdifferentialpairpassdownintoalowerlevelintheboardthrou

6、ghvias.ThevariousdielectricandmetallayerscameintoMWSinastraightforwardmannerfromAllegro.Inthesectionedviewshowntotheleftthedielectricsarehidden.Themetalforthesignalpathisshowninyellow,thatofgroundandsignallayersisgrey,andthepowerplanesareorange.Youcanseethattheviasarecomplexstructureswithpa

7、dsandantipadsateachlayerandwithashortstubattheend.Allofthesefeaturescouldscattersignalanddegradethesignalintegrity.4SonnetSoftware,Inc.(315)453-3096mwssupport@sonnetsoftware.comCurrentOnAViaInA22-LayerBoardThisfigureshowstheinstantaneouscurrentat10GHzont