实用的PICmicro振荡器的分析与设计
Thereisawealthofinformationwrittenonthesubject
ofdesigningandanalyzingoscillatorcircuits.Sources
rangefromacademicandresearchpaperstoindustry
generatedapplicationguides.Itisadauntingtaskfor
theembeddeddesignertoworkthroughalltheavail-
ableandsometimesconflictinginformation.Allthe
designerisreallyinterestedinisasimplesetofrules
resultinginareliableoscillatordesignthatwillwork
despitecrystalaging,deviationsbetweendevices,
temperatureorvoltage.Theproblemisthesimple
CrystalPierceGateOscillator(Figure1)hasa“simpli-
fied”model(Figure2)thatisanythingbutsimple.None
ofthevaluesarefixed.Somevarywithprocess,age,
temperatureandvoltage.Somecomponentshavea
nonlinearbehaviorwithamplitude.AN943PracticalPICmicroOscillatorAnalysisandDesignThepurposeofthisdocumentistoexplainthemostAuthor:RuanLourenscriticalaspectstodesigningandanalyzingareliableMicrochipTechnologyInc.PICmicroMCUbasedoscillator.Note:ReadingapplicationnotesAN826,CrystalOscillatorBasicsandCrystalSelectionforINTRODUCTIONrfPICandPICmicroDevicesan