电容测试条件(经典)

CapacitanceandDissipationFactorMeasurementofChipMultilayerCeramicCapacitorsPage1.Introduction--------------------------------------------------------------12.CharacteristicsofChipMultilayerCapacitors-------------------12-1.TemperatureCharacteristic2-2.VoltageCharacteristic(1)ACVoltageCharacteristic(2)DCBiasCharacteristic2-3.FrequencyCharacteristic2-4.Summary3.LCRMetersandMeasurementJigs-------------------------------63-1.LCRMeters3-2.MeasurementJigs4.LCRMeterMeasurementPrinciple--------------------------------74-1.MeasurementPrinciple4-2.MeasuringVoltage4-3.CapacitanceMeasurementCircuitMode5.CapacitanceMeasurementbyLCRMeter4284A--------------106.CapacitanceMeasurementbyLCRMeter4278A--------------147.Closing--------------------------------------------------------------------18References------------------------------------------------------------------18TDNo.C10EMurataMfg.Co.,Ltd.-1-1.IntroductionWhenyoumeasureahighdielectricMLCCcapacitor(X7R-characteristicorY5V-characteristic)usingaLCRmeter,theremaybeacaseyoucannotobtainareasonablecapacitancevaluewithinitsnominalrange.AscapacitanceanddissipationfactoroftheseTemperaturecharacteristicMLCCcapacitorssignificantlychangeaccordingtothemeasurementtemperature,voltage(AC,DC)andfrequency.Oneofthereasonsofsuchafailuretoobtainareasonablecapacitancecanbethatyourhavenotperformedthemeasurementcorrectlyusingspecifiedmeasurementconditions.Anotherreasonmaybeanincorrectmetersettingoruseofmeasurementequipmentthatdoesnothavethecapabilityneededforaccuratemeasurement.SolutionsfortheformerissueistofullyunderstandcharacteristicsofMLCCcapacitorsandtheappropriate“three(3)measuringconditions”,i.e.measuringtemperature,voltage(ACandDC)andfrequency.TheactualmeasurementconditionsofcapacitanceanddissipationfactorofhighdielectricceramiccapacitorsareshowninTable1below.Thetemperatureusedfortheseconditionsis25degree:Table1MeasuringConditionsNominalCapacitanceMeasuringFrequencyMeasuringVoltageC≤10µF(10Vorgreater)1±0.1kHz1.0±0.2VrmsC≤10µF(6.3Vorless)1±0.1kHz0.5±0.1VrmsC10µF120±24Hz0.5±0.1VrmsThesolutionforthesecondissueistounderstandthecapabilityofthemeasurementequipmenttobeusedandtoconfirmthatitmeetsthemeasurementconditionslistedinTable1.Inthisbrochure,wewillfirstdescribethecharacteristicsoftheMLCCcapacitorsthatcanaffectcapacitanceanddissipationfactormeasurement.Next,themeasuringprincipleoftheLCRmetersusedforactualmeasurementisdescribed,thenanexampleofthecorrectmethodusedtomeasurethecapacitanceanddissipationfactoroftheMLCCcapacitorsisexplained.2.CharacteristicsoftheMLCC(MultilayerCeramicChip)CapacitorsTheMLCCcapacitorshaveexcellentfeaturessuchassmallsize,highreliability,lowimpedanceandno-polarity,etc.,butontheotherhand,theyhavedemeritssuchascapacitancechangewithtemperatureorvoltagechange.Inthefollowingsections,measurementsof1206type10µFX7R-characteristicandY5V-characteristicMLCCcapacitorsaretakenupasexamplestoexplainthevariouscharacteristicsthatcanaffectthemeasurementofcapacitanceanddissipationfactor.-2-2-1.TemperatureCharacteristicTemperaturecharacteristicsofMLCCcapacitorsareshowninFig.1below:Atthemeasurementconditionsof1kHz,1Vrms,whereascapacitancechangeratiooftheX7R-characteristiciswithin±10%atmaximum,TheY5V-characteristiccapacitorisallowedtooverawiderrangeof+30%/-80%.Dissipationfactoralsochangesaccordingtomeasurementtemperature,whichtendstogoupinlowertemperaturesforbothX7R-andY5V-characteristiccapacitors.(a)CapacitanceChangeRatio(b)DissipationFactor(DF)Fig.1TemperatureCharacteristic1206type10uF10V-100-80-60-40-20020-75-50-250255075100125150Temp[Degree]Cap.change[%]X7RY5V1206type10uF10V0.00.10.20.30.40.5-75-50-250255075100125150Temp[Degree]DFX7RY5V-3-2-2.VoltageCharacteristic(1)ACVoltageCharacteristicTheACvoltagecharacteristicsofX7R-andY5V-characteristicMLCCcapacitorsareshowninFig.2below:Atthemeasurementconditionsof25degree,1kHz,whilecapacitancechangeratiooftheX7R-characteristiccapacitorsiswithin±5%atmaximum,thecapacitanceofY5V-characteristiccapacitorsdropsby50%atthemaximumandchangesaccordingtoappliedACvoltagelevel.AlthoughthedissipationfactorofY5V-characteristiccapacitoralsochangessignificantlyaccordingtothemeasurementvoltage,theX7R-characteristiccapacitorshowsverylittlechange.(a)CapacitanceChangeRatio(b)DissipationFactor(DF)Fig.2ACVoltageCharacteristic1206type10uF10V-100-80-60-40-2002000.511.52ACVoltage[Vrms]Cap.change[%]X7RY5V1206type10uF10V0.000.050.100.150.200.2500.511.52ACVoltage[Vrms]DFX7RY5V-4-(2)DCBiasCharacteristicTheDCbiascharacteristicsofX7R-andY5V-characteristicMLCCcapacitorsareshowninFig.3below:Atthemeasurementconditionsof25degree,1kHz,1vrms,thecapacitanceoftheX7R-characteristiccapacitordropsbyamaximumof60%accordingtoDCbiasvoltageapplied,whilethecapacitanceoftheY5V-characteristiccapacitordropsasmuchas90%.ThecapacitanceofMLCCcapacitorsdecreasesasappliedDCbiasvoltageincreases.AlsodissipationfactorsofthosecapacitorscomesdownasDCbiasvoltagegoesup.(a)CapacitanceChangeRatio(b)DissipationFactor(DF)Fig.3DCBiasCharacteristic1206type10uF10V-100-80-60-40-200200246810DCBias[Vdc]Cap.change[%