标签: crystals

TurningtoDigitalCrystalsinGSMTransceiversTurningtoDigitalCrystalsinGSMTransceiversVC-TCXOmodulesbringasizeandcostpenaltytonext-generationGSMhandsetdesigns.Fortunately,DCXOsarchitecturesareemergingthatwilladdressessizeandcostconcernsinmobiles.Today,mostGSMhandsetsusevoltage-controlled,temperature-compensatedcrystaloscillator(VC-TCXO)modulesasthesystemreferenceoscillator.Toestablishandmaintainarobustwirelessconnection,thereferenceoscillatormustattainhighlevelsofprecisionandaccuracy.Sinceaccuracyovertimeiscriticalinawirelessphonedesign,thereferenceoscillatormustbeabletocompensateforbothstaticanddynamicerrors.VC-TCXOmodulesmeettheserequirementsthroughanalogtechniquestocorrectfrequencydevi……

SelectionandSpecificationofCrystalsforTexasInstrumentsUSB2ApplicationReportSLLA122-December2002SelectionandSpecificationofCrystalsforTexasInstrumentsUSB2.0DevicesJulieMcElligattConnectivitySolutionsPeripheralApplicationsABSTRACTEveryUSBhigh-speedapplicationmustsupportadatarateof480Mb/swithin±500ppm(479.760Mb/sto480.240Mb/s)tocomplywiththeUniversalSerialBusSpecificationRevision2.0.ForTexasInstrumentsUSB2.0devices,itisrecommendedthattheclocksoftheUSB2.0devicesbederivedfromanexternalcrystal.Evaluationofthepropertiesofthecrystalwillensurethattheselectedcrystalwillfunctionasexpectedinthesystem.Capacitorselectionandlayoutcanalsoaffecttheoperationofthecrystal.Thisapplicationnotedetailsthepreferredcrystalproperties,aswellasguidelinesf……

SelectingCrystalsForStableOscillatorsqiyan307@52RDSelectingCrystalsForStableOscillatorsUnderstandinghowquartz-crystalresonatorsoperatecanleadtodesigningcrystaloscillatorswithimprovedstabilityandbetternoiseperformance.OscillatorsarecriticalcomponentsinRFanddigitaldesigns.Althoughoscillatorcircuitrymayalreadybeprovidedaspartofanintegratedcircuit(IC),aproduct-designengineermaystillberequiredtoselectthecrystalresonatorandexternalcapacitors.Toachievefinalproductsuccess,itisimportantthatthedesignerhasabasicunderstandingofhowanoscillatorandcrystalfunctiontoselectthecorrectcrystalandexternalcapacitorsforthedevice.Poorcrystalselectioncanleadtoaproductthatdoesnotoperateproperly,failsprematurely,orwillnotoperateoverthein……