LDO 详细介绍

SERVICESERVICESERVICESERVICEIIIINTEGRITYNTEGRITYNTEGRITYNTEGRITYINNOINNOINNOINNOVVVVATIONATIONATIONATIONSSSSHARINGHARINGHARINGHARINGLowDropoutRegulatorGMTFAE：Billy.ChenMAIL：[e-mail]：13590497418致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidential你需要知道什么你需要知道什么1.1.1.1.LDOLDOLDOLDO的定义2.2.2.2.LDOLDOLDOLDO的基本拓朴和操作3.3.3.3.LDOLDOLDOLDO的重要参数4.4.4.4.RFLDORFLDORFLDORFLDO的特性5.5.5.5.PCBLAYOUTPCBLAYOUTPCBLAYOUTPCBLAYOUT建议6.6.6.6.温度管理致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidentialLDOLDOLDOLDOLDOLDOLDOLDO的定义的定义LDOLDOLDOLDOLinearRegulatorLinearRegulatorLinearRegulatorLinearRegulatorLoadLoadLoadLoadVinVinVinVinVoutVoutVoutVoutVVVVdropoutdropoutdropoutdropoutLDOLDOLDOLDO就是在输入输出间只需要较小的压差的线性电压调整器VdropoutVdropoutVdropoutVdropout：在正常输出电压时调整输入电压，当输出电压下降到额定输出电压的98%98%98%98%时，输入与输出的电压差为DropDropDropDrop电压，（注意，带不同负载时有不同的DropDropDropDrop电压）致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidentialLDOLDOLDOLDOLDOLDOLDOLDO的基本拓朴的基本拓朴PassElementPassElementPassElementPassElementErrorAmpErrorAmpErrorAmpErrorAmpVoltageDividerVoltageDividerVoltageDividerVoltageDividerVoltageReferenceVoltageReferenceVoltageReferenceVoltageReferenceP-MOSFETLDOP-MOSFETLDOP-MOSFETLDOP-MOSFETLDO具有更简单的驱动，更低的RdsRdsRdsRds值。但P-MOSP-MOSP-MOSP-MOS的成本更高StructureofCMOSLDORegulatorStructureofCMOSLDORegulatorStructureofCMOSLDORegulatorStructureofCMOSLDORegulator致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidentialLDOLDOLDOLDOLDOLDOLDOLDO的基本拓朴的基本拓朴PPPPNPNPNPNP电晶体LDOLDOLDOLDO具有高输入电压的优点，但同时需要更高的DropDropDropDrop电压BasecurrentisrequiredBasecurrentisrequiredBasecurrentisrequiredBasecurrentisrequiredStructureofBipolarLDORegulatorStructureofBipolarLDORegulatorStructureofBipolarLDORegulatorStructureofBipolarLDORegulator致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidential常见的五种结构常见的五种结构VdoVdoVdoVdo=2V~3V=2V~3V=2V~3V=2V~3VVdoVdoVdoVdo=1.2V~1.3V=1.2V~1.3V=1.2V~1.3V=1.2V~1.3VVdoVdoVdoVdo=0.3V~0.6V=0.3V~0.6V=0.3V~0.6V=0.3V~0.6VVdo=RonXIoutVdo=RonXIoutVdo=RonXIoutVdo=RonXIoutVdo=RonXIoutVdo=RonXIoutVdo=RonXIoutVdo=RonXIout致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidentialLDOLDOLDOLDOLDOLDOLDOLDO的线性操作模式的线性操作模式LinearRegionLinearRegionLinearRegionLinearRegionSaturationRegionSaturationRegionSaturationRegionSaturationRegionIVCurveofMOSTransistorIVCurveofMOSTransistorIVCurveofMOSTransistorIVCurveofMOSTransistorVinVinVinVinVoutVoutVoutVout0000致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidentialLDOLDOLDOLDOLDOLDOLDOLDO的的工作原理工作原理输出电压经反馈电阻RsRsRsRs和RfRfRfRf分压，产生输出电压VfbVfbVfbVfb，并和基准电压（VrefVrefVrefVref）经相误差放大器作比较。通过此误差放大器向输出晶体管提供必要的门极电压，而使输出电压不受输入电压或温度变化的影响而保持一定。需特别注意的是CMOSCMOSCMOSCMOS制程的LDOLDOLDOLDO因寄生二极管的存在，当VoutVoutVoutVout的电位高于VinVinVinVin时，有可能因反向电流而导致ICICICIC损坏。因此，请注意VoutVoutVoutVout不要超过Vin+0.3vVin+0.3vVin+0.3vVin+0.3v以上致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidential几个重要的参数几个重要的参数11111111（（DROPDROPDROPDROPDROPDROPDROPDROP电压）电压）Definition:Definition:Definition:Definition:VVVVdropoutdropoutdropoutdropout=IoXRon=IoXRon=IoXRon=IoXRon,usingMOSFETasthepasstransistor,usingMOSFETasthepasstransistor,usingMOSFETasthepasstransistor,usingMOSFETasthepasstransistor•TheminimumvoltagedifferencebetweentheinputvoltageandtheoutputTheminimumvoltagedifferencebetweentheinputvoltageandtheoutputTheminimumvoltagedifferencebetweentheinputvoltageandtheoutputTheminimumvoltagedifferencebetweentheinputvoltageandtheoutputvoltage,whichstillproducearegulatedoutputvoltageundermaximumvoltage,whichstillproducearegulatedoutputvoltageundermaximumvoltage,whichstillproducearegulatedoutputvoltageundermaximumvoltage,whichstillproducearegulatedoutputvoltageundermaximumoperationloadcondition.operationloadcondition.operationloadcondition.operationloadcondition.致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidential几个重要的参数几个重要的参数22222222（（静态电流静态电流））•ThesupplycurrentusedbytheregulatoritselfthatdoesnotpassThesupplycurrentusedbytheregulatoritselfthatdoesnotpassThesupplycurrentusedbytheregulatoritselfthatdoesnotpassThesupplycurrentusedbytheregulatoritselfthatdoesnotpassintotheload.intotheload.intotheload.intotheload.Definition:Definition:Definition:Definition:致新科技股份有限公司GGGGloballoballoballobalMMMMixed-modeixed-modeixed-modeixed-modeTTTTechnologyInc.echnologyInc.echnologyInc.echnologyInc.GMTConfidential几个重要的参