A Topical Index of TI LDO Application Notes (Rev. E)

1 ApplicationReportSBVA026E February2010 RevisedFebruary2015A TopicalIndexof TI ,PowerManagementProductsABSTRACTT hisdocumentsummarizesa collectionof applicationnotesfromTexasInstrumentsthat discusslow-dropout(LDO) shortabstractof eachapplicationnoteand categorizesthe seriesof documentsby arrangedin suchan orderthat lessexperiencedreaderscan workthroughthesedocumentsfrombeginningto end withoutthe needto gobackand this documentis identifiedby title and a uniqueTI summarydescriptionof the articleor reportalsocontainsa link to the TexasInstrumentswebsite( ). Unlessotherwisenoted,all materialssummarizedin this documentcan be PowerSolution, purposeof this reportis to providea quickreferencedocumentfor applicationdesignersand otheruserswho are interestedin TI applicationreportdiscussedin thisdocumentis identifiedby title and by a uniqueTI literaturenumber,as shownin Example1.

2 If you wishtoaccessa completeversionof a givenreport,clickon the documentliteraturenumber(SBxx###orSLxx## #).This tag providesa hyperlinkto the documentlocationon , whereyou can eitherreadthe documentin its entiretyor downloadit for SampleEntryThermalParametersand MetricsUsingNewThermalMetrics: reportdiscussesthe practicalapplicationof two new thermalmetrics, JTand JB, to estimatesiliconjunctiontemperatureusinga n illustratedanalogyof Ohm'slaw. Additionally,this applicationreportexplainswhy traditionalthermalparameters(suchas JAor JC) are not recommendedfor determiningthe actualthermalperformanceof assistancewith LDOproductselection,referto the LDOQ uickReferenceSelectiontool, alsoavailableon ,ANY-OUTare trademarksof othertrademarksare the propertyof February2010 RevisedFebruary2015A TopicalIndexof TI LDOA pplicationNotesSubmitDocumentationFeedba ckCopyright 2010 2015,TexasInstrumentsIncorporatedBasicOv erviewof reportis dividedinto thesetopicalareas: BasicOverviewof LDOA rchitecture TechnicalReviewsof LDOP erformance RecentLDOT echnologyTrends Real-WorldLDOA pplications TPS75005-SpecificNotes Older-GenerationPMOSLDO sand ESRIf you havean applicationquestion,contactthe LinearRegulatorForumon the TI E2E Community.

3 (Notethat this link requiresa securelog-in.)2 BasicOverviewof LDOA rchitectureThis sectionreviewsseveralapplicationnotestha t explainthe architectureof LDOsor presenta generaldiscussionof Definitionsfor LDOsUnderstandingthe Termsand Definitionsof LDOV oltageRegulators: documentis a goodstartingpointto is somewhatdated,it clearlydescribeskey terminologiesrelatedto LDOsusinga goodrangeof notemakesa goodfoundationfromwhichto readthe otherapplicationnotesintroducedin this importantpointto noteis that contemporarydevicevendors(includingTexas Instruments)usebothPMOSand NMOSas passelementsbetweenIN and OUTon a case-by-casebasis,althoughthisnoteonly refersto Low-DropoutVoltageRegulatorOperationand Performance: documentcan be seenas an LDOtextbookwhencoupledwithUnderstandingt he TermsandDefinitionsof LDOV oltageRegulators(SLVA079). This noteis somewhatdatedas document,it is recommendedto reviewthe reportslistedin textbookcontainsa seriesof applicationreportsthat explainthe specificperformancecharacteristicsand parametersof SwitchingVoltageRegulatorFundamentalPart 1: SNVA558is also a textbook-styledocumentthat explainsthe basicsof P-TypePassFET LDOsFundamentalTheoryof PMOSLow-DropoutVoltageRegulators: documentexplainshow the PMOS-passFET functionswith notefocuseson PMOSLDOs,it helpsreadersunderstandNMOSLDOsas :Theoryof Operationand Compensation: SNVA020 AandApplicationNote1482 LDOR egulatorStabilityUsingCeramicOutputCapac itors.

4 ControltheorybehindLDOoperationin detailbut in an TopicalIndexof TI LDOA pplicationNotesSBVA026E February2010 RevisedFebruary2015 SubmitDocumentationFeedbackCopyright 2010 2015, LDOP erformance3 TechnicalReviewof LDOP erformanceThis sectionprovidesa summaryof applicationnotesthat DropOut (LDO)Regulators: reportexplainsthe differencesbetweenseriesregulatorsand also discussestypicalconcernsaboutlow : documentexplainshow to use the dropoutspecificationsfor a givenLDOdeviceto alignwith acustomer' LinearRegulators: articleexplainsthe typesof noisegeneratedfroman LDOdeviceitself,and discussesthe majornoisesourceswithina the total amountof noiseon the outputof an LDOdeviceisthe sum of noisefromthe LDOand any noisecomingfromthe for outputnoisecomingfromthe inputvoltage,we mustlook atPSRR,and considerthe LDOas a noisefilter fromIN to Detail: SLYT489in the4Q 2012 IssueAnalogApplicationsJournal: articleexplainshow to reduceLDOnoisefromthe viewpointof a a uniqueminimumnoiselevelfor eachdeviceafteroptimizingits (PSRR)UnderstandingPower-SupplyRippleRej ectionin LinearRegulators: reportexplainsthe performanceparameter,PSRR,as a reasonablemeasureof the abilityof anLDOto workas a OutputVoltageAccuracyEffectof ResistorToleranceson PowerSupplyAccuracy.

5 Reportexamineshow externalresistortolerancesaffectthe accuracyof s Guideto LinearVoltageRegulatorsand ThermalManagement: documentexplainsthe basicprinciplesof thermalmanagementin a step-by-stepmannerwithmanyexamples;it presentsthe informationin ,it is recommendedto followup withUsingNewThermalMetrics, MetricsUsingNewThermalMetrics: reportdiscussesthe practicalapplicationof two new thermalmetrics, JTand JB, to estimatesiliconjunctiontemperatureusinga n illustratedanalogyof Ohm'slaw. Additionally,this applicationreportexplainswhy traditionalthermalparameters(suchas JAor JC) are not recommendedfordeterminingthe actualthermalperformanceof ,PowerLoss,and ThermalParametersPackagingLimitsRangeof LinearRegulators: applicationnoteexplainsthe importanceof packageselectionin termsof the packagecapabilityto handleheat(powerdissipation) notecautionsusersto : applicationnoteexplainshow the performanceof a PMOSLDO regulatorchangeswhentheinput-to-outputvo ltagedecreasesto approachthe February2010 RevisedFebruary2015A TopicalIndexof TI LDOA pplicationNotesSubmitDocumentationFeedba ckCopyright 2010 2015, Consof Usinga FeedforwardCapacitorProsand Consof Usinga Feed-ForwardCapacitorwith a Low DropoutRegulator.

6 LDOapplications,a feed-forwardcapacitor(CFF) improvesthe stability,outputnoise,load transientresponse,and power -supplyrejectionratio(PSRR)of the ;however,thereare severalissuesthat mustbe sectionreviewsseveralapplicationnotestha t addressrecenttechnologiesusedin TI VeryLow-NoiseLDOD eviceGet Low-Noise,Low-Ripple,High-PSRRP owerwith the TPS717xx: reportintroducesthe TPS717xx, one of the highest-performanceLDOsfromTI. It also describeshow the TPS717xxdevicecan offerhigh PSRRand low (UltralowDropout)LDOD eviceA 3-A, 80%Efficiencyand PLOST< 1 W: documentintroducesthe TPS742xx, TPS743xx, and TPS744xxseriesof devices:ultralowdropoutLDOsfor applicationswith over1-A describesthe devicefamilyfeaturesas the TPS720xx: applicationnotediscussesa new implementationof the current-limitfunction,whichgivesconstant power -uptime dependingonly on the outputcapacitorvalue,regardlessof the load currentconnectedduringthe (DynamicVoltageScaling)LDOS avingValuableBoardSpacewith DynamicVoltageScalingin PortableDevices: articleintroducesa functionthat allowstwo presetoutputvoltagesto be switchedby one featureis very valuablewhenusingsupplyprocessorsthat requiretwo voltages.

7 One for anormalor activestate,and the secondfor a traditionalmethodsto achievethis type of configurationusingexternalcomponents,thi s dynamicvoltage-scalingfunctionsavesbothb oardspaceand LDOR egulators: documentdescribesthe historyand detailsof outputcapacitor-freeLDOdevices,suchas theREG101, REG102, REG103, TPS731, TPS736, and TPS742xx, TPS743xx, and documentis not a recentpublication,and refersprimarilyto the REG10xseries,itoffersan excellentexplanationof how a : SNVA337also coversthe : reportcomparesthe processof inrushcurrentcontrolby usingexternalcomponentsand also illustratesthe benefitof an Stressof Start-Up: SNVA333also coversthe the TPS74x01 Familyof LinearRegulators: documentintroducesa voltage-trackingfunctionof the trackingfeature,a devicepower-downsequencecan be achievedvery TopicalIndexof TI LDOA pplicationNotesSBVA026E February2010 RevisedFebruary2015 SubmitDocumentationFeedbackCopyright 2010 2015, FixedOutputVoltageVersionsof TPS742xx/TPS743xx/TPS744 noteintroducesthe possibilityof a very accurateoutputvoltagesolutionusinga fixed-voltageversionof the TPS742xx, TPS743xx, and TPS744xxseriesof the ClockOscillatorSupplyNoiseEffecton OscillatorPhaseNoise: notediscussesthe low-noisepowerrail for RF clockdevicesand concludesthat a low-noiseLDO(suchas the TPS742xx) is preferablefor the Noisein RF ApplicationsLDON oiseDemystified: notediscussesthe differenceof two importantLDOparameters.

8 Noiseand RF applicationsand are CommunicationSystems(MagazineArticle)Gre goryWaterfall,MasashiNogawa,and DheepanSundaram,Powersupplychallengesin dataandvoicecommunicationsystems, ECN,Apr 19, articlediscussesLDOpowercleanlinessand performanceof downstream, (MagazineArticle)Nogawa,Masashiand Van Renterghem,Kyle,"WideBandwidthPSRRof LDOs", Bodo's PowerSystems, pp. 46-49,Mar articlediscussesPSRR bandwidthand real-worldripplerejectionof (MagazineArticle)Stokes,William,"WhatGiv esat Dropout?Low dropoutregulatorperformanceneardropout", ECN,Dec 15, Pair of High-Voltage,Low-Noise,Positiveand NegativeLDO(MagazineArticle)Hunter,Pat, "Designingan ultra-low-noisesupplyfor analogcircuits", ElectronicProducts,Mar 1, articleintroducesa pair of high-voltagepositiveand negativeLDOs(TPS7A4901andTPS7A3001).5 Real-WorldLDOA pplicationsThis sectionreviewsseveralapplicationnotestha t MeasurePSRRLDOPSRRM easurementSimplified: documentexplainshow to measurePSRRin also presentsa CheckFeedbackLoopStabilitySimplifyingSta bilityChecks: reportexplainshow to checkfeedbackloop stabilityon a thoroughway to checkthe loop stabilityis to use a frequency-responseanalyzer,thisapproachi nvolvesa lot of difficultyfor engineerswho wishto frequency-responseanalyzeris not alwayscommonequipmentin manylabs,and is also feedbackloop by cuttingthe printedcircuitboard(PCB)pattern.

9 Theseloopsare unableto be cut with somerecenthigh-performanceLDOdevicesbeca usethesedeviceshavemultipleloopswithinth e ,this loop-cuttingproceduremay also affectthe actualworkingconditionson an techniquesdiscussedin this noteenableloop stabilityto be checkedwith commonlab loop can be checkedin normaloperatingconditionson the techniqueis alsobasedon a firm academictheory,and it is not just an February2010 RevisedFebruary2015A TopicalIndexof TI LDOA pplicationNotesSubmitDocumentationFeedba ckCopyright 2010 2015, ExtendLDOI nputVoltageExtendingthe InputVoltageRangeof an LDOR egulator: articleexplainshow to use an LDOwith an inputvoltagethat exceedsthe techniqueis helpfulfor usinga preferredor performanceLDOin a widerrangeof ExpandLDOO utputVoltageUnderIts V Usingan ExternalReference: SLVA216,High-CurrentLDOL inearRegulators(UCCx81-ADJ,UCx82-ADJ,UCC x83-ADJ,UCx85-ADJ): SLUA256, andLow Power150-mA : to use an LDOthat suppliesan outputvoltagelowerthanitsreferencevoltag eby tweakingthe feedbackcircuitrywith ExpandLDOO utputCurrentby Parallel(LoadSharing)OperationBallastRes istorsAllowLoadSharingBetweenTwo ParallelDC/DCConverters: reportexplainshow to use multipleregulatorsin parallelto title, this documentis fully relevantto ExpandLDOO utputCurrentby ExternalPNPE xternalPNPT ransistorBoostsTPS71501 OutputCurrent: documentexplainshow to expandthe LDOoutputcurrentby connectinga PNPunderthe controlof the High-EfficiencyRegulatorhas Low Drop-OutVoltage: SNOA587 Aalso Makean LDOSoft-StartSoft-StartCircuitsfor LDOL inearRegulators: SLYT096andMonotonic,InrushCurrentLimited Start-Up for LinearRegulators.

10 Documentsexplainhow to achievethe soft-startfunctionof an LDOoutputwith theconfigurationof someLDOdeviceswith an integratedsoft-startfunction,the rangeof availabledevicesdoesnot coverall usefulfor addinga soft-startfunctionto the closestdevicefor a Use a CeramicCapacitorfor Tantalum-OnlyLDOsCeramicCapacitorsReplac eTantalumCapacitorsin LDOs: noteexplainshow to use a ceramiccapacitorat the outputof an LDOthat EstimateLDOJ unction-to-AmbientThermalResistanceMeasu ringthe ThermalImpedanceof LDOsin Situ: noteexplainshow to estimateR JAfromthe thermalshutdownfunctionof LDOas I2C controlledpowersolutionANY-OUT LDOC ontrolledby I 2 C IO ExpanderDevice: noteshowsthe demoof an ANY-OUTLDO workingas I2C powerwith I2C IO Use PowerSolutionsto ExtendMSP430 ApplicationBatteryLifeUsingPowerSolution sto ExtendBatteryLife in MSP430 applications : reportshowstwo simplebut effectivepowersolutionsthat furtherminimizeMSP430powerconsumptionand Picka LinearRegulatorfor Noi