Product Order Technical Tools & Support & Folder Now Documents Software Community LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 LM2574x SIMPLE SWITCHER® 0.5-A Step-Down Voltage Regulator 1 Features 3 Description • 3.3-V,5-V,12-V,15-V,andAdjustableOutput The LM2574xx series of regulators are monolithic 1 integrated circuits that provide all the active functions Versions for a step-down (buck) switching regulator, capable of • AdjustableVersionOutputVoltageRange:1.23V driving a 0.5-A load with excellent line and load to37V(57VforHVversion)±4%MaximumOver regulation.Thesedevicesareavailableinfixedoutput LineandLoadConditions voltages of 3.3 V, 5 V, 12 V, 15 V, and an adjustable • Specified0.5-AOutputCurrent outputversion. • WideInputVoltageRange:40V,upto60Vfor Requiring a minimum number of external HVVersion components, these regulators are simple to use and • RequiresOnly4ExternalComponents include internal frequency compensation and a fixed- frequencyoscillator. • 52-kHzFixed-FrequencyInternalOscillator The LM2574xx series offers a high-efficiency • TTLShutdownCapability,Low-PowerStandby replacement for popular three-terminal linear Mode regulators. Because of its high efficiency, the copper • HighEfficiency traces on the printed-circuit board (PCB) are normally • UsesReadilyAvailableStandardInductors theonlyheatsinkingneeded. • ThermalShutdownandCurrent-LimitProtection A standard series of inductors optimized for use with • CreateaCustomDesignUsingtheLM2574With the LM2574 are available from several different theWEBENCH®PowerDesigner manufacturers. This feature greatly simplifies the designofswitch-modepowersupplies. 2 Applications Other features include a specified ±4% tolerance on • SimpleHigh-EfficiencyStep-Down(Buck) output voltage within specified input voltages and output load conditions, and ±10% on the oscillator Regulator frequency. External shutdown is included, featuring • EfficientPreregulatorforLinearRegulators 50-μA (typical) standby current. The output switch • On-CardSwitchingRegulators includes cycle-by-cycle current limiting, as well as • Positive-to-NegativeConverter(Buck-Boost) thermal shutdown for full protection under fault conditions. DeviceInformation(1) PARTNUMBER PACKAGE BODYSIZE(NOM) SOIC(14) 8.992mm×7.498mm LM2574,LM2574HV PDIP(8) 6.35mm×9.81mm (1) For all available packages, see the orderable addendum at theendofthedatasheet. TypicalApplication(FixedOutputVoltageVersions) 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Table of Contents 1 Features.................................................................. 1 7.3 FeatureDescription.................................................11 2 Applications........................................................... 1 7.4 DeviceFunctionalModes........................................13 3 Description............................................................. 1 8 ApplicationandImplementation........................ 14 4 RevisionHistory..................................................... 2 8.1 ApplicationInformation............................................14 8.2 TypicalApplications................................................19 5 PinConfigurationandFunctions......................... 3 9 PowerSupplyRecommendations...................... 26 6 Specifications......................................................... 4 10 Layout................................................................... 26 6.1 AbsoluteMaximumRatings......................................4 6.2 ESDRatings..............................................................4 10.1 LayoutGuidelines.................................................26 6.3 RecommendedOperatingConditions.......................4 10.2 LayoutExample....................................................27 6.4 ThermalInformation..................................................4 10.3 Grounding.............................................................27 6.5 ElectricalCharacteristicsforAllOutputVoltage 10.4 ThermalConsiderations........................................27 Versions.....................................................................5 11 DeviceandDocumentationSupport................. 29 6.6 ElectricalCharacteristics–3.3-VVersion.................5 11.1 DeviceSupport......................................................29 6.7 ElectricalCharacteristics–5-VVersion....................6 11.2 DocumentationSupport........................................31 6.8 ElectricalCharacteristics–12-VVersion..................6 11.3 ReceivingNotificationofDocumentationUpdates31 6.9 ElectricalCharacteristics–15-VVersion..................6 11.4 CommunityResources..........................................31 6.10 ElectricalCharacteristics–AdjustableVersion.......7 11.5 Trademarks...........................................................31 6.11 TypicalCharacteristics............................................8 11.6 ElectrostaticDischargeCaution............................31 7 DetailedDescription............................................ 11 11.7 Glossary................................................................31 7.1 Overview.................................................................11 12 Mechanical,Packaging,andOrderable 7.2 FunctionalBlockDiagram.......................................11 Information........................................................... 31 4 Revision History ChangesfromRevisionD(April2016)toRevisionE Page • AddedlinksforWEBENCH ................................................................................................................................................... 1 • maximumsupplyvoltageinAbsMaxRatingsfrom"4.5"to"45"tocorrecttypo................................................................... 4 ChangesfromRevisionC(April2013)toRevisionD Page • AddedDeviceInformationtable,ESDRatingstable,FeatureDescriptionsection,DeviceFunctionalModes, ApplicationandImplementationsection,PowerSupplyRecommendationssection,Layoutsection,Deviceand DocumentationSupportsection,andMechanical,Packaging,andOrderableInformationsection ..................................... 1 • ChangedR valueinSOICcolumnto77.1 ........................................................................................................................ 4 θJA • SplittestconditionsrowoftheElectricalCharacteristicstabletoincludeT =25°CandT <25°CMIN,TYP,and J J MAXvalues............................................................................................................................................................................. 5 • SplittestconditionsinI rowtorearrangetheMIN,TYP,andMAXvalues ......................................................................... 5 L ChangesfromRevisionB(November2004)toRevisionC Page • ChangedlayoutofNationalDataSheettoTIformat............................................................................................................. 1 2 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 5 Pin Configuration and Functions PPackage 8-PinPDIP NPAPackage TopView 14-PinSOIC TopView FB 1 8 NC NC 1 14 NC SIG_GND 2 7 OUTPUT NC 2 13 NC ON/OFF 3 6 NC FB 3 12 OUTPUT PWR_GND 4 5 V   IN SIG_GND 4 11 NC ON/OFF 5 10 V   IN PWR_GND 6 9 NC NC 7 8 NC PinFunctions PIN I/O DESCRIPTION NAME PDIP SOIC Feedbacksenseinputpin.Connecttothemidpointoffeedbackdividertoset FB 1 3 I VOUTforADJversionorconnectthispindirectlytotheoutputcapacitorfora fixedoutputversion. 1,2,7,8,9, NC 8,6 — Nointernalconnection,butmustbesolderedtoPCBforbestheattransfer. 11,13,14 Enableinputtothevoltageregulator.High=OFFandlow=ON.Connectto ON/OFF 3 5 I GNDtoenablethevoltageregulator.Donotleavethispinfloat. Emitterpinofthepowertransistor.Thisisaswitchingnode.Attachedthispin OUTPUT 7 12 O toaninductorandthecathodeoftheexternaldiode. Powergroundpins.ConnecttosystemgroundandSIFGND,groundpinsof PWR_GND 4 6 — C andC .PathtoC mustbeasshortaspossible. IN OUT IN Signalgroundpin.Groundreferenceforinternalreferencesandlogic.Connect SIG_GND 2 4 — tosystemground. Supplyinputpintocollectorpinofhigh-sidetransistor.Connecttopower V 5 10 I supplyandinputbypasscapacitorsC .PathfromVINpintohighfrequency IN IN bypassC andPWRGNDmustbeasshortaspossible. IN Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1) MIN MAX UNIT LM2574 45 Maximumsupplyvoltage V LM2574HV 63 ON/OFFpininputvoltage –0.3 V V IN Outputvoltagetoground,steady-state –1 V Powerdissipation Internallylimited Leadtemperature,soldering(10s) 260 °C Maximumjunctiontemperature 150 °C Storagetemperature,T –65 150 °C stg (1) StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratings only,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommended OperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. 6.2 ESD Ratings VALUE UNIT V Electrostaticdischarge Human-bodymodel(HBM),perANSI/ESDA/JEDECJS-001(1) ±2000 V (ESD) (1) JEDECdocumentJEP155statesthat500-VHBMallowssafemanufacturingwithastandardESDcontrolprocess. 6.3 Recommended Operating Conditions overoperatingfree-airtemperaturerange(unlessotherwisenoted) MIN NOM MAX UNIT LM2574 40 Supplyvoltage V LM2574HV 60 T Temperature –40 125 °C J 6.4 Thermal Information LM2574,LM2574HV THERMALMETRIC(1)(2) P(PDIP) NPA(SOIC) UNIT 8PINS 14PINS R Junction-to-ambientthermalresistance(3) 60.4 77.1 °C/W θJA R Junction-to-case(top)thermalresistance(3) 59.9 29.2 °C/W θJC(top) R Junction-to-boardthermalresistance(3) 37.9 33.3 °C/W θJB ψ Junction-to-topcharacterizationparameter 17.1 2 °C/W JT ψ Junction-to-boardcharacterizationparameter 37.7 32.8 °C/W JB R Junction-to-case(bottom)thermalresistance(3) — — °C/W θJC(bot) (1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheSemiconductorandICPackageThermalMetricsapplication report. (2) ThepackagethermalimpedanceiscalculatedinaccordancewithJESD51-7. (3) Thermalresistancesweresimulatedona4-layer,JEDECboard. 4 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 6.5 Electrical Characteristics for All Output Voltage Versions T =25°C,andMINandMAXapplyoverfulloperatingtemperaturerange.V =12Vforthe3.3-V,5-V,andadjustable J IN version,V =25Vforthe12-Vversion,andV =30Vforthe15-Vversion,I =100mA(unlessotherwisenoted). IN IN LOAD PARAMETER TESTCONDITIONS MIN(1) TYP MAX(1) UNIT Adjustableversion TJ=25°C 50 100 I Feedbackbiascurrent nA b only,VOUT=5V –40°C<TJ<125°C 500 T =25°C 47 52 58 f Oscillatorfrequency See(2) J kHz O –40°C<T <125°C 42 63 J T =25°C 0.9 1.2 V Saturationvoltage I =0.5A(3) J V SAT OUT –40°C<T <125°C 1.4 J DC Maximumdutycycle(ON) See(4) 93% 98% 0.7 1 1.6 I Currentlimit Peakcurrent(2)(3) A CL 0.65 1.8 Output=0V 2 I Currentoutputleakage mA L Output=–1V(5)(6) 7.5 30 I Quiescentcurrent See(5) 5 10 mA Q I Standbyquiescentcurrent ON/OFFpin=5V(OFF) 50 200 μA STBY ON/OFFCONTROL(SEEFigure27) T =25°C 2.2 1.4 J V V =0V V IH OUT –40°C<T <125°C 2.4 J ON/OFFpinlogicinputlevel V VOUT=Nominaloutput TJ=25°C 1.2 1 V IL voltage –40°C<T <125°C 0.8 J I ON/OFFpin=5V(OFF) 12 30 μA H ON/OFFpininputcurrent I ON/OFFpin=0V(ON) 0 10 μA IL (1) AlllimitsspecifiedatroomtemperatureTYPandMAX.Allroomtemperaturelimitsare100%productiontested.Alllimitsattemperature extremesarespecifiedthroughcorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedtocalculate AverageOutgoingQualityLevel. (2) Theoscillatorfrequencyreducestoapproximately18kHzintheeventofanoutputshortoranoverloadwhichcausestheregulated outputvoltagetodropapproximately40%fromthenominaloutputvoltage.Thisselfprotectionfeaturelowerstheaveragepower dissipationoftheICbyloweringtheminimumdutycyclefrom5%downtoapproximately2%(seeFigure6). (3) Outputpinsourcingcurrent.Nodiode,inductororcapacitorconnectedtooutputpin. (4) Feedbackpinremovedfromoutputandconnectedto0V. (5) Feedbackpinremovedfromoutputandconnectedto12Vfortheadjustable,3.3-V,and5-Vversions,and25Vforthe12-Vand15-V versions,toforcetheoutputtransistorOFF. (6) V =40V(60Vforhighvoltageversion). IN 6.6 Electrical Characteristics – 3.3-V Version T =25°C,andallMINandMAXapplyoverfulloperatingtemperaturerange(unlessotherwisenoted). J PARAMETER(1) TESTCONDITIONS MIN(2) TYP MAX(2) UNIT V =12V,I =100mA 3.234 3.3 3.366 IN LOAD LM2574,4.75V≤VIN≤40V, TJ=25°C 3.168 3.3 3.432 VOUT Outputvoltage 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 3.135 3.465 V LM2574HV,4.75V≤VIN≤60V, TJ=25°C 3.168 3.3 3.45 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 3.135 3.482 η Efficiency V =12V,I =0.5A 72% IN LOAD (1) TestCircuitinFigure22andFigure27. (2) Alllimitsspecifiedatroomtemperatureandattemperatureextremes.Allroomtemperaturelimitsare100%productiontested.Alllimits attemperatureextremesarespecifiedviacorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedto calculateAverageOutgoingQualityLevel. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 6.7 Electrical Characteristics – 5-V Version T =25°C,andallMINandMAXapplyoverfulloperatingtemperaturerange(unlessotherwisenoted). J PARAMETER(1) TESTCONDITIONS MIN TYP(2) MAX(2) UNIT V =12V,I =100mA 4.9 5 5.1 IN LOAD LM2574,7V≤VIN≤40V, TJ=25°C 4.8 5 5.2 VOUT Outputvoltage 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 4.75 5.25 V LM2574HV,7V≤VIN≤60V, TJ=25°C 4.8 5 5.225 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 4.75 5.275 η Efficiency V =12V,I =0.5A 77% IN LOAD (1) TestcircuitinFigure22andFigure27. (2) AlllimitsspecifiedatroomtemperatureTYPandMAX.Allroomtemperaturelimitsare100%productiontested.Alllimitsattemperature extremesarespecifiedthroughcorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedtocalculate AverageOutgoingQualityLevel. 6.8 Electrical Characteristics – 12-V Version T =25°C,andallMINandMAXapplyoverfulloperatingtemperaturerange(unlessotherwisenoted). J PARAMETER(1) CONDITIONS MIN TYP(2) MAX(2) UNIT V =25V,I =100mA 11.76 12 12.24 IN LOAD LM2574,15V≤VIN≤40V, TJ=25°C 11.52 12 12.48 VOUT Outputvoltage 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 11.4 12.6 V LM2574HV,15V≤VIN≤60V, TJ=25°C 11.52 12 12.54 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 11.4 12.66 η Efficiency V =15V,I =0.5A 88% IN LOAD (1) TestcircuitinFigure22andFigure27. (2) AlllimitsspecifiedatroomtemperatureTYPandMAX.Allroomtemperaturelimitsare100%productiontested.Alllimitsattemperature extremesarespecifiedthroughcorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedtocalculate AverageOutgoingQualityLevel. 6.9 Electrical Characteristics – 15-V Version T =25°C,andallMINandMAXapplyoverfulloperatingtemperaturerange(unlessotherwisenoted). J PARAMETER(1) TESTCONDITIONS MIN TYP(2) MAX(2) UNIT V =30V,I =100mA 14.7 15 15.3 IN LOAD LM2574,18V≤VIN≤40V, TJ=25°C 14.4 15 15.6 VOUT Outputvoltage 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 14.25 15.75 V LM2574HV,18V≤VIN≤60V, TJ=25°C 14.4 15 15.68 0.1A≤ILOAD≤0.5A −40°C≤TJ≤125°C 14.25 15.83 η Efficiency V =18V,I =0.5A 88% IN LOAD (1) TestcircuitinFigure22andFigure27. (2) AlllimitsspecifiedatroomtemperatureTYPandMAX.Allroomtemperaturelimitsare100%productiontested.Alllimitsattemperature extremesarespecifiedthroughcorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedtocalculate AverageOutgoingQualityLevel. 6 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 6.10 Electrical Characteristics – Adjustable Version T =25°C,andallMINandMAXapplyoverfulloperatingtemperaturerange.V =12V,I =100mA(unlessotherwise J IN LOAD noted). PARAMETER(1) TESTCONDITIONS MIN TYP(2) MAX(2) UNIT V =12V,I =100mA 1.217 1.23 1.243 IN LOAD LM2574,7V≤V ≤40V, T =25°C 1.193 1.23 1.267 IN J 0.1A≤I ≤0.5A, LOAD VFB Feedbackvoltage VOUTprogrammedfor5V −40°C≤TJ≤125°C 1.18 1.28 V LM2574HV,7V≤V ≤60V, T =25°C 1.193 1.23 1.273 IN J 0.1A≤I ≤0.5A, LOAD VOUTprogrammedfor5V −40°C≤TJ≤125°C 1.18 1.286 η Efficiency V =12V,V =5V,I =0.5A 77% IN OUT LOAD (1) TestcircuitinFigure22andFigure27. (2) AlllimitsspecifiedatroomtemperatureTYPandMAX.Allroomtemperaturelimitsare100%productiontested.Alllimitsattemperature extremesarespecifiedthroughcorrelationusingstandardStatisticalQualityControl(SQC)methods.Alllimitsareusedtocalculate AverageOutgoingQualityLevel. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 6.11 Typical Characteristics SeeFigure27. Figure1.NormalizedOutputVoltage Figure2.LineRegulation Figure3.DropoutVoltage Figure4.CurrentLimit Figure5.SupplyCurrent Figure6.StandbyQuiescentCurrent 8 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Typical Characteristics (continued) SeeFigure27. Figure7.OscillatorFrequency Figure8.SwitchSaturationVoltage Figure9.Efficiency Figure10.MinimumOperatingVoltage Figure11.SupplyCurrentvsDutyCycle Figure12.FeedbackVoltagevsDutyCycle Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Typical Characteristics (continued) SeeFigure27. Figure13.FeedbackPinCurrent Figure14.Junction-to-AmbientThermalResistance 10 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 7 Detailed Description 7.1 Overview The LM2574 SIMPLE SWITCHER® regulator is an easy-to-use, non-synchronous, step-down DC-DC converter with a wide input voltage range from 40 V to up to 60 V for a HV version. It is capable of delivering up to 0.5-A DC load current with excellent line and load regulation. These devices are available in fixed output voltages of 3.3 V, 5 V, 12 V, 15 V, and an adjustable output version. The family requires few external components and the pinarrangementwasdesignedforsimple,optimumPCBlayout. 7.2 Functional Block Diagram V IN Unregulated Internal ON / OFF 5 ON / OFF 3 DC Input Regulator + 1 Feedback CIN R2 Fixed Gain Error Amp + Compatator 0.5 Amp + Switch R1 – – DRIVER Output L1 VOUT 7 2 + SGigNnaDl 1.23 V D1 COUT L BAND – GAP 52 kHz Thermal Current O REFRENCE OSCILLATOR Reset Shutdown Limit 4 A D Pwr Gnd Copyright © 2016, Texas Instruments Incorporated Note:Pinnumbersareforthe8-pinPDIPpackage R1=1k 3.3V,R2=1.7k 5V,R2=3.1k 12V,R2=8.84k 15V,R2=11.3k Foradjustableversion, R1=Open,R2=0Ω 7.3 Feature Description 7.3.1 CurrentLimit The LM2574 device has current limiting to prevent the switch current from exceeding safe values during an accidental overload on the output. This value (I ) can be found in Electrical Characteristics for All Output CL VoltageVersions. 7.3.2 UndervoltageLockout In some applications, it is desirable to keep the regulator off until the input voltage reaches a certain threshold. An undervoltage lockout circuit which accomplishes this task is shown in Figure 15 while Figure 16 shows the same circuit applied to a buck-boost configuration. These circuits keep the regulator off until the input voltage reachesapredeterminedlevelinEquation1. V ≈V +2V (1) TH Z1 BE Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Feature Description (continued) Note:Completecircuitnotshown(seeFigure20). Note:Pinnumbersarefor8-pinPDIPpackage. Figure15. UndervoltageLockoutforBuckCircuit Note:Completecircuitnotshown(seeFigure20). Note:Pinnumbersarefor8-pinPDIPpackage. Figure16. UndervoltageLockoutforBuck-BoostCircuit 7.3.3 DelayedStart-Up The ON/OFF pin can be used to provide a delayed start-up feature as shown in Figure 17. With an input voltage of 20 V and for the part values shown, the circuit provides approximately 10 ms of delay time before the circuit begins switching. Increasing the RC time constant can provide longer delay times. But excessively large RC time constants can cause problems with input voltages that are high in 60-Hz or 120-Hz ripple, by coupling the ripple intotheON/OFFpin. 7.3.4 AdjustableOutput,Low-RipplePowerSupply A 500-mA power supply that features an adjustable output voltage is shown in Figure 18. An additional L-C filter thatreducestheoutputripplebyafactorof10ormoreisincludedinthiscircuit. 12 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Feature Description (continued) Note:Completecircuitnotshown. Note:Pinnumbersarefor8-pinPDIPpackage. Figure17. DelayedStart-Up Note:Pinnumbersarefor8-pinPDIPpackage. Figure18. 1.2-Vto55-VAdjustable500-mAPowerSupplyWithLow-OutputRipple 7.4 Device Functional Modes 7.4.1 ShutdownMode The ON/OFF pin provides electrical ON and OFF control for the LM2574. When the voltage of this pin is higher than1.4V,thedeviceisshutdownmode.Thetypicalstandbycurrentinthismodeis50 μA. 7.4.2 ActiveMode When the voltage of the ON/OFF pin is below 1.2 V, the device starts switching and the output voltage rises until itreachesanormalregulationvoltage. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validateandtesttheirdesignimplementationtoconfirmsystemfunctionality. 8.1 Application Information 8.1.1 InputCapacitor(C ) IN To maintain stability, the regulator input pin must be bypassed with at least a 22-μF electrolytic capacitor. The leadsofthecapacitormustbekeptshort,andlocatedneartheregulator. If the operating temperature range includes temperatures below −25°C, the input capacitor value may need to be larger. With most electrolytic capacitors, the capacitance value decreases and the ESR increases with lower temperatures and age. Paralleling a ceramic or solid tantalum capacitor increases the regulator stability at cold temperatures. For maximum capacitor operating lifetime, the RMS ripple current rating of the capacitor must be greaterthanEquation2. t 1.2´ ON ´I T LOAD where t V ON = OUT T V • IN forabuckregulator t V ON = OUT T V +V • OUT IN forabuck-boostregulator (2) 8.1.2 InductorSelection All switching regulators have two basic modes of operation: continuous and discontinuous. The difference betweenthetwotypesrelatestotheinductorcurrent,whetheritisflowingcontinuously,orifitdropstozerofora period of time in the normal switching cycle. Each mode has distinctively different operating characteristics, whichcanaffecttheregulatorperformanceandrequirements. The LM2574 (or any of the SIMPLE SWITCHER family) can be used for both continuous and discontinuous modesofoperation. In many cases the preferred mode of operation is in the continuous mode. It offers better load regulation, lower peak switch, inductor, and diode currents, and can have lower output ripple voltage. But it does require relatively largeinductorvaluestokeeptheinductorcurrentflowingcontinuously,especiallyatlowoutputloadcurrents. To simplify the inductor selection process, an inductor selection guide (nomograph) was designed. This guide assumes continuous mode operation, and selects an inductor that allows a peak-to-peak inductor ripple current (ΔI ) to be a certain percentage of the maximum design load current. In the LM2574 SIMPLE SWITCHER, the IND peak-to-peak inductor ripple current percentage (of load current) is allowed to change as different design load currents are selected. By allowing the percentage of inductor ripple current to increase for lower current applications,theinductorsizeandvaluecanbekeptrelativelylow. 8.1.3 InductorRippleCurrent When the switcher is operating in the continuous mode, the inductor current waveform ranges from a triangular to a sawtooth type of waveform (depending on the input voltage). For a given input voltage and output voltage, the peak-to-peak amplitude of this inductor current waveform remains constant. As the load current rises or falls, the entire sawtooth current waveform also rises or falls. The average DC value of this waveform is equal to the DCloadcurrent(inthebuckregulatorconfiguration). 14 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Application Information (continued) If the load current drops to a low enough level, the bottom of the sawtooth current waveform reaches zero, and the switcher changes to a discontinuous mode of operation. This is a perfectly acceptable mode of operation. Any buck switching regulator (no matter how large the inductor value is) is forced to run discontinuous if the load currentislightenough. ThecurveshowninFigure19illustrateshowthepeak-to-peakinductorripplecurrent(ΔI )isallowedtochange IND as different maximum load currents are selected, and also how it changes as the operating point varies from the upperbordertothelowerborderwithinaninductanceregion(seeInductorSelection). Figure19. InductorRippleCurrent(Δi )Range IND Considerthefollowingexample: V =5Vat0.4A OUT V =10-Vminimumupto20-Vmaximum IN The selection guide in Figure 24 shows that for a 0.4-A load current, and an input voltage range between 10 V and 20 V, the inductance region selected by the guide is 330 μH. This value of inductance allows a peak-to-peak inductor ripple current (ΔI ) to flow that is a percentage of the maximum load current. For this inductor value, IND the ΔI also varies depending on the input voltage. As the input voltage increases to 20 V, it approaches the IND upper border of the inductance region, and the inductor ripple current increases. Referring to the curve in Figure 19, it can be seen that at the 0.4-A load current level, and operating near the upper border of the 330-μH inductanceregion,theΔI is53%of0.4A,or212mA . IND p-p This ΔI is important because from this number the peak inductor current rating can be determined, the IND minimum load current required before the circuit goes to discontinuous operation, and also, knowing the ESR of the output capacitor, the output ripple voltage can be calculated, or conversely, measuring the output ripple voltageandknowingthe ΔI ,theESRcanbecalculated. IND From the previous example, the peak-to-peak inductor ripple current (ΔI ) = 212 mA . When the Δ value is IND p-p IND known, the following three formulas can be used to calculate additional information about the switching regulator circuit: 1. PeakinductororpeakswitchcurrentinEquation3. æ DI ö æ 212ö =çèILOAD + 2IND ÷ø=çè0.4 A+ 2 ÷ø=506mA (3) 2. MinimumloadcurrentbeforethecircuitbecomesdiscontinuousinEquation4. DI 212 = IND = =106mA 2 2 (4) 3. Outputripplevoltage=(ΔI )×(ESRofC ) IND OUT Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Application Information (continued) The selection guide chooses inductor values suitable for continuous mode operation, but if the inductor value chosenisprohibitivelyhigh,thedesignershouldinvestigatethepossibilityofdiscontinuousoperation. Inductors are available in different styles such as pot core, toroid, E-frame, bobbin core, and so forth, as well as different core materials, such as ferrites and powdered iron. The least expensive, the bobbin core type, consists of wire wrapped on a ferrite rod core. This type of construction makes for an inexpensive inductor, but because the magnetic flux is not completely contained within the core, it generates more electro-magnetic interference (EMI). This EMl can cause problems in sensitive circuits, or can give incorrect scope readings because of inducedvoltagesinthescopeprobe. The inductors listed in the selection chart include powdered iron toroid for Pulse Engineering, and ferrite bobbin coreforRenco. An inductor must not be operated beyond its maximum rated current because it may saturate. When an inductor begins to saturate, the inductance decreases rapidly and the inductor begins to look mainly resistive (the DC resistance of the winding). This can cause the inductor current to rise very rapidly and affects the energy storage capabilities of the inductor and could cause inductor overheating. Different inductor types have different saturation characteristics, and consider this when selecting an inductor. The inductor manufacturers' data sheets includecurrentandenergylimitstoavoidinductorsaturation. 8.1.4 OutputCapacitor An output capacitor is required to filter the output voltage and is needed for loop stability. The capacitor must be located near the LM2574 using short PCB traces. Standard aluminum electrolytics are usually adequate, but low ESR types are recommended for low output ripple voltage and good stability. The ESR of a capacitor depends on many factors, some which are: the value, the voltage rating, physical size, and the type of construction. In general,low-valueorlow-voltage(lessthan12V)electrolyticcapacitorsusuallyhavehigherESRnumbers. Theamountofoutputripplevoltageisprimarilyafunctionoftheequivalentseriesresistance(ESR)oftheoutput capacitorandtheamplitudeoftheinductorripplecurrent, ΔI (seeInductorRippleCurrent(Δi )). IND IND The lower capacitor values (100 μF to 330 μF) allows typically 50 mV to 150 mV of output ripple voltage, while larger-valuecapacitorsreducetherippletoapproximately20mVto50mV(asseeninEquation5). OutputRippleVoltage=(ΔI )(ESRofC ) (5) IND OUT To further reduce the output ripple voltage, several standard electrolytic capacitors may be paralleled, or a higher-grade capacitor may be used. Such capacitors are often called high-frequency, low-inductance, or low- ESR. These reduce the output ripple to 10 mV or 20 mV. However, when operating in the continuous mode, reducingtheESRbelow0.03Ω cancauseinstabilityintheregulator. Tantalum capacitors can have a very low ESR, and must be carefully evaluated if it is the only output capacitor. Because of their good low temperature characteristics, a tantalum can be used in parallel with aluminum electrolytics,withthetantalummakingup10%or20%ofthetotalcapacitance. The ripple current rating of the capacitor at 52 kHz must be at least 50% higher than the peak-to-peak inductor ripplecurrent. 8.1.5 CatchDiode Buckregulatorsrequireadiodetoprovideareturnpathfortheinductorcurrentwhentheswitchisoff.Thisdiode mustbelocatedclosetotheLM2574usingshortleadsandshortprinted-circuittraces. Because of their fast switching speed and low forward voltage drop, Schottky diodes provide the best efficiency, especially in low output voltage switching regulators (less than 5 V). fast-recovery, high-efficiency, or ultra-fast recovery diodes are also suitable, but some types with an abrupt turnoff characteristic may cause instability and EMI problems. A fast-recovery diode with soft recovery characteristics is a better choice. Standard 60-Hz diodes (for example, 1N4001 or 1N5400, and so forth) are also not suitable. See Table 1 for Schottky and soft fast- recoverydiodeselectionguide. 16 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Table1.DiodeSelectionGuide 1-ADIODES V R SCHOTTKY FASTRECOVERY 1N5817 20V SR102 MBR120P 1N5818 SR103 Thefollowingdiodesareallratedto100V 30V 11DQ03 MBR130P 10JQ030 1N5819 SR104 11DF1 40V 11DQ04 10JF1 11JQ04 MUR110 MBR140P HER102 MBR150 SR105 50V 11DQ05 11JQ05 MBR160 SR106 60V 11DQ06 11JQ06 90V 11DQ09 8.1.6 OutputVoltageRippleandTransients The output voltage of a switching power supply contains a sawtooth ripple voltage at the switcher frequency, typically about 1% of the output voltage, and may also contain short voltage spikes at the peaks of the sawtooth waveform. TheoutputripplevoltageisduemainlytotheinductorsawtoothripplecurrentmultipliedbytheESRoftheoutput capacitor(seeInductorSelection). The voltage spikes are present because of the fast switching action of the output switch, and the parasitic inductance of the output filter capacitor. To minimize these voltage spikes, special low inductance capacitors can be used, and their lead lengths must be kept short. Wiring inductance, stray capacitance, as well as the scope probeusedtoevaluatethesetransients,allcontributetotheamplitudeofthesespikes. An additional small LC filter (20 μH and 100 μF) can be added to the output (as shown in Figure 18) to further reduce the amount of output ripple and transients. A 10 × reduction in output ripple voltage and transients is possiblewiththisfilter. 8.1.7 FeedbackConnection The LM2574 (fixed voltage versions) feedback pin must be wired to the output voltage point of the switching power supply. When using the adjustable version, physically locate both output voltage programming resistors near the LM2574 to avoid picking up unwanted noise. Avoid using resistors greater than 100 kΩ because of the increasedchanceofnoisepickup. 8.1.8 ON/OFFInput For normal operation, the ON/OFF pin must be grounded or driven with a low-level TTL voltage (typically less than 1.6 V). To put the regulator into standby mode, drive this pin with a high-level TTL or CMOS signal. The ON/OFF pin can be safely pulled up to +V without a resistor in series with it. The ON/OFF pin must not be left IN open. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 8.1.9 AdditionalApplications 8.1.9.1 InvertingRegulator Figure 20 shows a LM2574-12 in a buck-boost configuration to generate a negative 12-V output from a positive input voltage. This circuit bootstraps the ground pin of the regulator to the negative output voltage, then by groundingthefeedbackpin,theregulatorsensestheinvertedoutputvoltageandregulatesitto −12V. Note:Pinnumbersareforthe8-pinPDIPpackage. Figure20. InvertingBuck-BoostDevelops,12V For an input voltage of 8 V or more, the maximum available output current in this configuration is approximately 100mA.Atlighterloads,theminimuminputvoltagerequireddropstoapproximately4.7V. The switch currents in this buck-boost configuration are higher than in the standard buck-mode design, thus lowering the available output current. Also, the start-up input current of the buck-boost converter is higher than the standard buck-mode regulator, and this may overload an input power source with a current limit less than 0.6 A. Using a delayed turnon or an undervoltage lockout circuit (described in Negative Boost Regulator) would allowtheinputvoltagetorisetoahighenoughlevelbeforetheswitcherwouldbeallowedtoturnon. Because of the structural differences between the buck and the buck-boost regulator topologies, the design procedure can not be used to select the inductor or the output capacitor. The recommended range of inductor values for the buck-boost design is between 68 μH and 220 μH, and the output capacitor values must be larger than what is normally required for buck designs. Low-input voltages or high-output currents require a large value outputcapacitor(inthethousandsofmicroFarads). Thepeakinductorcurrent,whichisthesameasthepeakswitchcurrent,canbecalculatedfromEquation6. I »ILOAD´(VIN+ VOUT )+ VIN´ VOUT ´ 1 P V V + V 2´L ´f IN IN OUT 1 OSC where • f =52kHz.Undernormalcontinuousinductorcurrentoperatingconditions, osc • theminimumV representstheworstcase.Selectaninductorthatisratedforthepeakcurrentanticipated. IN (6) Also, the maximum voltage appearing across the regulator is the absolute sum of the input and output voltage. Fora−12-Voutput,themaximuminputvoltagefortheLM2574is28V,or48VfortheLM2574HV. 8.1.9.2 NegativeBoostRegulator Another variation on the buck-boost topology is the negative boost configuration. The circuit in Figure 21 accepts an input voltage ranging from −5 V to −12 V and provides a regulated −12-V output. Input voltages greater than −12Vcausestheoutputtorisegreaterthan −12V,butdoesnotdamagetheregulator. 18 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Note:Pinnumbersarefor8-pinPDIPpackage. Figure21. NegativeBoost Because of the boosting function of this type of regulator, the switch current is relatively high, especially at low input voltages. Output load current limitations are a result of the maximum current rating of the switch. Also, boost regulators can not provide current-limiting load protection in the event of a shorted load, so some other means(suchasafuse)maybenecessary. 8.2 Typical Applications 8.2.1 FixedOutputVoltageApplications C :22μF,75V IN Aluminumelectrolytic C :220μF,25V OUT Aluminumelectrolytic D1:Schottky,11DQ06 L1:330μH,52627 (for5Vin,3.3Vout,use 100μH,RL-1284-100) R1:2k,0.1% R2:6.12k,0.1% Figure22. FixedOutputVoltageVersions Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Typical Applications (continued) 8.2.1.1 DesignRequirements ThedesignrequirementsforthefixedoutputvoltageapplicationisprovidedinTable2. Table2.DesignParameters PARAMETER EXAMPLEVALUE Regulatedoutputvoltage(3.3V,5V,12V,or15V),V 5V OUT Maximuminputvoltage,V (Max) 15V IN Maximumloadcurrent,I (Max) 0.4A LOAD 8.2.1.2 DetailedDesignProcedure 8.2.1.2.1 CustomDesignWithWEBENCH®Tools ClickheretocreateacustomdesignusingtheLM2574devicewiththeWEBENCH® PowerDesigner. 1. Startbyenteringtheinputvoltage(V ),outputvoltage(V ),andoutputcurrent(I )requirements. IN OUT OUT 2. Optimizethedesignforkeyparameterssuchasefficiency,footprint,andcostusingtheoptimizerdial. 3. ComparethegenerateddesignwithotherpossiblesolutionsfromTexasInstruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricingandcomponentavailability. Inmostcases,theseactionsareavailable: • Runelectricalsimulationstoseeimportantwaveformsandcircuitperformance • Runthermalsimulationstounderstandboardthermalperformance • ExportcustomizedschematicandlayoutintopopularCADformats • PrintPDFreportsforthedesign,andsharethedesignwithcolleagues GetmoreinformationaboutWEBENCHtoolsatwww.ti.com/WEBENCH. 8.2.1.2.2 InductorSelection(L1) Select the correct Inductor value selection guide from Figure 23, Figure 24, Figure 25, or Figure 26 (output voltagesof3.3V,5V,12V,or15Vrespectively). From the inductor value selection guide, identify the inductance region intersected by V (Max) and I (Max). IN LOAD Theinductanceareaintersectedbythe15-Vlineand0.4-Alineis330. Select an appropriate inductor from Table 3. Part numbers are listed for three inductor manufacturers. The inductor chosen must be rated for operation at the LM2574 switching frequency (52 kHz) and for a current rating of 1.5 × I . For additional inductor information, see Inductor Selection. The required inductor value is 330 μH. LOAD FromTable3,choosePulseEngineeringPE-52627,RencoRL-1284-330,orNPINP5920/5921. 20 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 Table3.InductorSelectionByManufacturer'sPartNumber INDUCTORVALUE PULSEENG. RENCO NPI 68μH * RL-1284-68-43 NP5915 100μH * RL-1284-100-43 NP5916 150μH 52625 RL-1284-150-43 NP5917 220μH 52626 RL-1284-220-43 NP5918/5919 330μH 52627 RL-1284-330-43 NP5920/5921 470μH 52628 RL-1284-470-43 NP5922 680μH 52629 RL-1283-680-43 NP5923 1000μH 52631 RL-1283-1000-43 * 1500μH * RL-1283-1500-43 * 2200μH * RL-1283-2200-43 * 8.2.1.2.3 OutputCapacitorSelection(C ) OUT The value of the output capacitor together with the inductor defines the dominate pole-pair of the switching regulator loop. For stable operation and an acceptable output ripple voltage, (approximately 1% of the output voltage) a value between 100 μF and 470 μF is recommended. C = 100-μF to 470-μF standard aluminum OUT electrolytic. Thevoltageratingofthecapacitormustbeatleast1.5timesgreaterthantheoutputvoltage.Fora5-Vregulator, a rating of at least 8 V is appropriate, and a 10-V or 15-V rating is recommended. Capacitor voltage rating = 20V. Higher voltage electrolytic capacitors generally have lower ESR numbers, and for this reason it may be necessarytoselectacapacitorratedforahighervoltagethanwouldnormallybeneeded. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 21 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 8.2.1.2.4 CatchDiodeSelection(D1) The catch-diode current rating must be at least 1.5 times greater than the maximum load current. Also, if the power supply design must withstand a continuous output short, the diode must have a current rating equal to the maximum current limit of the LM2574. The most stressful condition for this diode is an overload or shorted output condition.Forthisexample,a1-Acurrentratingisadequate. The reverse voltage rating of the diode must be at least 1.25 times the maximum input voltage. Use a 20-V 1N5817orSR102Schottkydiode,oranyofthesuggestedfast-recoverydiodesshowninTable1. 8.2.1.2.5 InputCapacitor(C ) IN An aluminum or tantalum electrolytic bypass capacitor located close to the regulator is needed for stable operation. A 22-μF aluminum electrolytic capacitor located near the input and ground pins provides sufficient bypassing. 8.2.1.3 ApplicationCurves Figure23.3.3-VLM2574HVInductorSelectionGuide Figure24.5-VLM2574HVInductorSelectionGuide Figure25.12-VLM2574HVInductorSelectionGuide Figure26.15-VLM2574HVInductorSelectionGuide 22 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 8.2.2 AdjustableOutputVoltageApplications Figure27. AdjustableOutputVoltageVersion 8.2.2.1 DesignRequirements ThedesignrequirementsforthefixedoutputvoltageapplicationisprovidedinTable4. Table4.DesignParameters PARAMETER EXAMPLEVALUE Regulatedoutputvoltage,V 24V OUT Maximuminputvoltage,V (Max) 40V IN Maximumloadcurrent,I (Max) 0.4A LOAD Switchingfrequency,F 52kHz 8.2.2.2 DetailedDesignProcedure 8.2.2.2.1 ProgrammingOutputVoltage SelectingR1andR2,asshowninFigure27. UseEquation7toselecttheappropriateresistorvalues. æ R ö VOUT = VREF´ç1+ R2÷ è 1ø where • V =1.23V (7) REF R can be between 1k and 5k as in Equation 8. For best temperature coefficient and stability with time, use 1% 1 metalfilmresistors. æV ö R2 =R1´çVOUT -1÷ è REF ø (8) Forthisexample,useEquation9andEquation10. æ R ö VOUT =1.23´ç1+ R2÷ è 1ø select • R1=1k (9) æV ö æ 24 V ö R2 =R1´çèVOREUFT -1÷ø=1k´çè1.23 V -1÷ø (10) R =1k(19.51−1)=18.51k,closest1%valueis18.7k 2 Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 23 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 8.2.2.2.2 InductorSelection(L1) CalculatetheinductorVolt× microsecondconstant,E ×T(V ×μs),fromEquation11. V 1000 E´T =(V -V )´ OUT ´ (V´µs) IN OUT V F(kHz) IN (11) Forthisexample,calculateE× T(V ×μs)usingEquation12. 24 1000 E´T =(40-24)´ ´ =185 V´µs 40 52 (12) Use the E × T value from the previous formula and match it with the E × T number on the vertical axis of the inductorvalueselectionguideshowninFigure32.Forthisexample,E ×T=185V × μs. Onthehorizontalaxis,selectthemaximumloadcurrent,I (Max)=0.4A. LOAD Identify the inductance region intersected by the E × T value and the maximum load current value, and note the inductorvalueforthatregion,inductanceregion=1000. Select an appropriate inductor from the table shown in Table 3. Part numbers are listed for three inductor manufacturers.TheinductorchosenmustberatedforoperationattheLM2574switchingfrequency(52kHz)and foracurrentratingof1.5 ×I .Foradditionalinductorinformation,seeInductorSelection. LOAD 8.2.2.2.3 OutputCapacitorSelection(C ) OUT The value of the output capacitor together with the inductor defines the dominate pole-pair of the switching regulatorloop.Forstableoperation,thecapacitormustsatisfytherequirementinEquation13. V C ³13300´ IN(MAX) (µF) OUT V ´L(µH) OUT (13) Equation 13 yields capacitor values between 5 μF and 1000 μF that satisfies the loop requirements for stable operation. But to achieve an acceptable output ripple voltage, (approximately 1% of the output voltage) and transientresponse,theoutputcapacitormayneedtobeseveraltimeslargerthantheaboveformulayields. Thevoltageratingofthecapacitormustbeatlast1.5timesgreaterthantheoutputvoltage.Fora24-Vregulator, a rating of at least 35 V is recommended. Higher voltage electrolytic capacitors generally have lower ESR numbers, and for this reasion it may be necessary to select a capacitor rate for a higher voltage than would normallybeneeded. 40 C >13300´ =22.2µF OUT 24´1000 (14) However,foracceptableoutputripplevoltageselect: C ≥100 μF OUT C =100μFelectrolyticcapacitor OUT 8.2.2.2.4 CatchDiodeSelection(D1) The catch-diode current rating must be at least 1.5 times greater than the maximum load current. Also, if the power supply design must withstand a continuous output short, the diode must have a current rating equal to the maximum current limit of the LM2574. The most stressful condition for this diode is an overload or shorted output condition.SuitablediodesareshowninTable1.Forthisexample,a1-Acurrentratingisadequate. The reverse voltage rating of the diode must be at least 1.25 times the maximum input voltage. Use a 50-V MBR150or11DQ05Schottkydiode,oranyofthesuggestedfast-recoverydiodesinTable1. 8.2.2.2.5 InputCapacitor(C ) IN An aluminum or tantalum electrolytic bypass capacitor located close to the regulator is needed for stable operation. A 22-μF aluminum electrolytic capacitor located near the input and ground pins provides sufficient bypassing(seeTable1). 24 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 8.2.2.3 ApplicationCurves Outputpinvoltage,10V/div, Horizontaltimebase, Outputpinvoltage,10V/div, Horizontaltimebase, Inductorcurrent,0.2A/div, 5μs/div, Inductorcurrent,0.2A/div, 5μs/div, Outputripplevoltage, V =5V, Outputripplevoltage, V =5V, OUT OUT 20mV/div, 500-mAloadcurrent, 20mV/div, 100-mAloadcurrent, AC-coupled L=330Μh AC-coupled L=100Μh Figure28.ContinuousModeSwitchingWaveforms Figure29.DiscontinuousModeSwitchingWaveforms Outputvoltage,50V/div, 500mAload, Outputvoltage,50V/div, 250mAload, AC-coupled, L=330Μh, AC-coupled, L=68Μh, 100-mAto500-mAloadpulse, COUT=300Μf, 50-mAto250-mAloadpulse, COUT=470Μf, Horizontaltimebase:200μs/div Horizontaltimebase:200μs/div Figure30.TransientResponsefor Figure31.TransientResponsefor ContinuousModeOperation DiscontinuousModeOperation Figure32.AdjustableLM2574HVInductorSelectionGuide Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 25 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com 9 Power Supply Recommendations As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductancegeneratevoltagetransientswhichcancauseproblems.Forminimalinductanceandgroundloops,the length of the leads indicated by heavy lines must be kept as short as possible. Single-point grounding (as indicated) or ground plane construction must be used for best results. When using the adjustable version, physicallylocatetheprogrammingresistorsneartheregulator,tokeepthesensitivefeedbackwiringshort. 10 Layout 10.1 Layout Guidelines The layout is critical for the proper operation of switching power supplies. First, the ground plane area must be sufficient for thermal dissipation purposes. Second, appropriate guidelines must be followed to reduce the effects of switching noise. Switch mode converters are very fast switching devices. In such cases, the rapid increase of input current combined with the parasitic trace inductance generates unwanted L di/dt noise spikes. The magnitude of this noise tends to increase as the output current increases. This noise may turn into electromagnetic interference (EMI) and can also cause problems in device performance. Therefore, take care in thelayouttominimizetheeffectofthisswitchingnoise. The most important layout rule is to keep the AC current loops as small as possible. Figure 33 shows the current flow in a buck converter. The top schematic shows a dotted line which represents the current flow during the top switch ON-state. The middle schematic shows the current flow during the top switch OFF-state. The bottom schematic shows the currents referred to as AC currents. These AC currents are the most critical because they arechanginginaveryshorttimeperiod.Thedottedlinesofthebottomschematicarethetracestokeepasshort and wide as possible. This also yields a small loop area reducing the loop inductance. To avoid functional problems due to layout, review the PCB layout example. Best results are achieved if the placement of the LM2574device,thebypasscapacitor,theSchottkydiode,RFBB,RFBT,andtheinductorareplacedasshownin the example. In the layout shown, R1 = RFBB and R2 = RFBT. TI also recommends using 2-oz. copper boards orheaviertohelpthermaldissipationandtoreducetheparasiticinductancesofboardtraces.Seetheapplication noteAN-1229SIMPLESWITCHER® PCBLayoutGuidelines (SNVA054)formoreinformation. Figure33. BuckConverterCurrentFlow 26 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 10.2 Layout Example Figure34. LM2574AdjustableOutputVoltageLayout 10.3 Grounding The 8-pin molded PDIP and the 14-pin SOIC package have separate power and signal ground pins. Both ground pins must be soldered directly to wide printed-circuit board copper traces to assure low inductance connections andgoodthermalproperties. 10.4 Thermal Considerations The 8-pin PDIP (P) package and the 14-pin SOIC (NPA) package are molded plastic packages with solid copper lead frames. The copper lead frame conducts the majority of the heat from the die, through the leads, to the printed-circuit board copper, which acts as the heat sink. For best thermal performance, wide copper traces must be used, and all ground and unused pins must be soldered to generous amounts of printed-circuit board copper, such as a ground plane. Large areas of copper provide the best transfer of heat (lower thermal resistance) to the surrounding air, and even double-sided or multilayer boards provide better heat paths to the surrounding air. Unless the power levels are small, using a socket for the 8-pin package is not recommended because of the additionalthermalresistanceitintroduces,andtheresultanthigherjunctiontemperature. Because of the 0.5-A current rating of the LM2574, the total package power dissipation for this switcher is quite low, ranging from approximately 0.1 W up to 0.75 W under varying conditions. In a carefully engineered printed- circuit board, both the P and the NPA package can easily dissipate up to 0.75 W, even at ambient temperatures of60°C,andstillkeepthemaximumjunctiontemperaturelessthan125°C. A curve, Figure 14, displaying thermal resistance versus PCB area for the two packages is shown in Typical Characteristics. These thermal resistance numbers are approximate, and there can be many factors that affect the final thermal resistance. Some of these factors include board size, shape, thickness, position, location, and board temperature. Other factors are, the area of printed-circuit copper, copper thickness, trace width, multi-layer, single- or double-sided, and the amount of solder on the board. The effectiveness of the PCB to dissipate heat also depends on the size, number and spacing of other components on the board. Furthermore, some of these components, such as the catch diode and inductor generate some additional heat. Also, the thermal resistance decreases as the power level increases because of the increased air current activity at the higher power levels, andthelowersurfacetoairresistancecoefficientathighertemperatures. The data sheet thermal resistance curves can estimate the maximum junction temperature based on operating conditions. ln addition, the junction temperature can be estimated in actual circuit operation by using Equation15. T =T +(θ ×P ) (15) j cu j-cu D Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 27 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Thermal Considerations (continued) With the switcher operating under worst case conditions and all other components on the board in the intended enclosure, measure the copper temperature (T ) near the IC. This can be done by temporarily soldering a small cu thermocouple to the PCB copper near the IC, or by holding a small thermocouple on the PCB copper using thermalgreaseforgoodthermalconduction. Thethermalresistance(θ )forthetwopackagesis: j-cu θ =42°C/WfortheP-8package j-cu θ =52°C/WfortheNPA-14package j-cu Thepowerdissipation(P )fortheICcouldbemeasured,oritcanbeestimatedbyusingEquation16. D V P = V ´I + OUT ´I ´V D IN S V LOAD SAT IN where • I isobtainedfromthetypicalsupplycurrentcurve(adjustableversionusethesupplycurrentvsdutycycle S curve) (16) 28 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 11 Device and Documentation Support 11.1 Device Support 11.1.1 Third-PartyProductsDisclaimer TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER ALONEORINCOMBINATIONWITHANYTIPRODUCTORSERVICE. 11.1.2 CustomDesignWithWEBENCH® Tools ClickheretocreateacustomdesignusingtheLM2574devicewiththeWEBENCH® PowerDesigner. 1. Startbyenteringtheinputvoltage(V ),outputvoltage(V ),andoutputcurrent(I )requirements. IN OUT OUT 2. Optimizethedesignforkeyparameterssuchasefficiency,footprint,andcostusingtheoptimizerdial. 3. ComparethegenerateddesignwithotherpossiblesolutionsfromTexasInstruments. The WEBENCH Power Designer provides a customized schematic along with a list of materials with real-time pricingandcomponentavailability. Inmostcases,theseactionsareavailable: • Runelectricalsimulationstoseeimportantwaveformsandcircuitperformance • Runthermalsimulationstounderstandboardthermalperformance • ExportcustomizedschematicandlayoutintopopularCADformats • PrintPDFreportsforthedesign,andsharethedesignwithcolleagues GetmoreinformationaboutWEBENCHtoolsatwww.ti.com/WEBENCH. 11.1.3 DeviceNomenclature 11.1.3.1 BuckRegulator A switching regulator topology in which a higher voltage is converted to a lower voltage. Also known as a step- downswitchingregulator. 11.1.3.2 Buck-BoostRegulator A switching regulator topology in which a positive voltage is converted to a negative voltage without a transformer. 11.1.3.3 DutyCycle(D) The ratio of the ON-time of the output switch to the oscillator period calculated with Equation 17 for buck regulatorsandEquation18forbuck-boostregulators. t V D= ON = OUT T V IN (17) t V D= ON = OUT T V +V OUT IN (18) 11.1.3.4 CatchDiodeorCurrentSteeringDiode ThisdiodeprovidesareturnpathfortheloadcurrentwhentheLM2574switchisOFF. Intermsofefficiency(η),theproportionofinputpoweractuallydeliveredtotheloadcalculatedwithEquation19. P P OUT OUT h= = P P +P IN OUT LOSS (19) Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 29 ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV SNVS104E–JUNE1999–REVISEDJULY2018 www.ti.com Device Support (continued) 11.1.3.5 CapacitorEquivalentSeriesResistance(ESR) The purely resistive component of a real capacitor's impedance (see Figure 35) can causes power loss resulting in capacitor heating, which directly affects the operating lifetime of the capacitor. When used as a switching regulatoroutputfilter,higherESRvaluesresultinhigheroutputripplevoltages. Figure35. SimpleModelOfARealCapacitor Moststandardaluminumelectrolyticcapacitorsinthe100μFto1000 μFrangehave0.5-Ω to0.1-Ω ESR.Higher- grade capacitors (low-ESR, high-frequency, or low-inductance) in the 100 μF to 1000 μF range generally have ESRoflessthan0.15 Ω. 11.1.3.6 EquivalentSeriesInductance(ESL) ThepureinductancecomponentofacapacitorisseeninFigure35.Theamountofinductanceisdeterminedtoa large extent on the capacitor's construction. In a buck regulator, this unwanted inductance causes voltage spikes toappearontheoutput. 11.1.3.7 OutputRippleVoltage The AC component of the output voltage of the switching regulator is usually dominated by the output capacitor's ESR multiplied by the inductor's ripple current (ΔI ). The peak-to-peak value of this sawtooth ripple current can IND bedeterminedbyreadingInductorRippleCurrent(Δi ). IND 11.1.3.8 CapacitorRippleCurrent The RMS value of the maximum allowable alternating current at which a capacitor can be operated continuously ataspecifiedtemperature. 11.1.3.9 StandbyQuiescentCurrent(I ) STBY Supply current required by the LM2574 when in the standby mode (ON/OFF pin is driven to TTL-high voltage, thusturningtheoutputswitchOFF). 11.1.3.10 InductorRippleCurrent(Δi ) IND The peak-to-peak value of the inductor current waveform, typically a sawtooth waveform when the regulator is operatinginthecontinuousmode(vs.discontinuousmode). 11.1.3.11 ContinuousandDiscontinuousModeOperation These mode operations relate to the inductor current. In the continuous mode, the inductor current is always flowing and never drops to zero, versus the discontinuous mode, where the inductor current drops to zero for a periodoftimeinthenormalswitchingcycle. 11.1.3.12 InductorSaturation The condition which exists when an inductor cannot hold any more magnetic flux. When an inductor saturates, the inductor appears less inductive and the resistive component dominates. Inductor current is then limited only bytheDCresistanceofthewireandtheavailablesourcecurrent. 11.1.3.13 OperatingVoltMicrosecondConstant(E ×T ) op The product (in VoIt × μs) of the voltage applied to the inductor and the time the voltage is applied. This E × T op constant is a measure of the energy handling capability of an inductor and is dependent upon the type of core, thecorearea,thenumberofturns,andthedutycycle. 30 SubmitDocumentationFeedback Copyright©1999–2018,TexasInstrumentsIncorporated ProductFolderLinks:LM2574 LM2574HV

LM2574,LM2574HV www.ti.com SNVS104E–JUNE1999–REVISEDJULY2018 11.2 Documentation Support 11.2.1 RelatedDocumentation Forrelateddocumentationseethefollowing: AN-1229SIMPLESWITCHER® PCBLayoutGuidelines,SNVA054 11.3 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed.Forchangedetails,reviewtherevisionhistoryincludedinanyreviseddocument. 11.4 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TIE2E™OnlineCommunity TI'sEngineer-to-Engineer(E2E)Community.Createdtofostercollaboration amongengineers.Ate2e.ti.com,youcanaskquestions,shareknowledge,exploreideasandhelp solveproblemswithfellowengineers. DesignSupport TI'sDesignSupport QuicklyfindhelpfulE2Eforumsalongwithdesignsupporttoolsand contactinformationfortechnicalsupport. 11.5 Trademarks E2EisatrademarkofTexasInstruments. WEBENCH,SIMPLESWITCHERareregisteredtrademarksofTexasInstruments. Allothertrademarksarethepropertyoftheirrespectiveowners. 11.6 Electrostatic Discharge Caution Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates. 11.7 Glossary SLYZ022—TIGlossary. Thisglossarylistsandexplainsterms,acronyms,anddefinitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of thisdocument.Forbrowser-basedversionsofthisdatasheet,refertotheleft-handnavigation. Copyright©1999–2018,TexasInstrumentsIncorporated SubmitDocumentationFeedback 31 ProductFolderLinks:LM2574 LM2574HV

PACKAGE OPTION ADDENDUM www.ti.com 7-Feb-2020 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) LM2574HVM-12/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -12 P+ LM2574HVM-15 NRND SOIC NPA 14 50 TBD Call TI Call TI -40 to 125 LM2574HVM -15 P+ LM2574HVM-15/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -15 P+ LM2574HVM-3.3/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -3.3 P+ LM2574HVM-5.0 NRND SOIC NPA 14 50 TBD Call TI Call TI -40 to 125 LM2574HVM -5.0 P+ LM2574HVM-5.0/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -5.0 P+ LM2574HVM-ADJ/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -ADJ P+ LM2574HVMX-12/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -12 P+ LM2574HVMX-15/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -15 P+ LM2574HVMX-3.3/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-4-260C-72 HR -40 to 125 LM2574HVM & no Sb/Br) -3.3 P+ LM2574HVMX-5.0 NRND SOIC NPA 14 1000 TBD Call TI Call TI -40 to 125 LM2574HVM -5.0 P+ LM2574HVMX-5.0/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -5.0 P+ LM2574HVMX-ADJ/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574HVM & no Sb/Br) -ADJ P+ LM2574HVN-12/NOPB ACTIVE PDIP P 8 40 Green (RoHS Call TI | SN Level-1-NA-UNLIM -40 to 125 LM2574HVN & no Sb/Br) -12 P+ LM2574HVN-15/NOPB ACTIVE PDIP P 8 40 Green (RoHS SN Level-1-NA-UNLIM -40 to 125 LM2574HVN & no Sb/Br) -15 P+ LM2574HVN-5.0/NOPB ACTIVE PDIP P 8 40 Green (RoHS SN Level-1-NA-UNLIM -40 to 125 LM2574HVN & no Sb/Br) -5.0 P+ LM2574HVN-ADJ/NOPB ACTIVE PDIP P 8 40 Green (RoHS SN Level-1-NA-UNLIM -40 to 125 LM2574HVN & no Sb/Br) -ADJ P+ Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 7-Feb-2020 Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) LM2574M-12/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -12 P+ LM2574M-3.3/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -3.3 P+ LM2574M-5.0 NRND SOIC NPA 14 50 TBD Call TI Call TI -40 to 125 LM2574M -5.0 P+ LM2574M-5.0/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -5.0 P+ LM2574M-ADJ NRND SOIC NPA 14 50 TBD Call TI Call TI -40 to 125 LM2574M -ADJ P+ LM2574M-ADJ/NOPB ACTIVE SOIC NPA 14 50 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -ADJ P+ LM2574MX-12/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -12 P+ LM2574MX-3.3/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-4-260C-72 HR -40 to 125 LM2574M & no Sb/Br) -3.3 P+ LM2574MX-5.0/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -5.0 P+ LM2574MX-ADJ/NOPB ACTIVE SOIC NPA 14 1000 Green (RoHS SN Level-3-260C-168 HR -40 to 125 LM2574M & no Sb/Br) -ADJ P+ LM2574N-12/NOPB ACTIVE PDIP P 8 40 Green (RoHS Call TI | SN Level-1-NA-UNLIM -40 to 125 LM2574N & no Sb/Br) -12 P+ LM2574N-3.3/NOPB ACTIVE PDIP P 8 40 Green (RoHS Call TI | SN Level-1-NA-UNLIM -40 to 125 LM2574N & no Sb/Br) -3.3 P+ LM2574N-5.0/NOPB ACTIVE PDIP P 8 40 Green (RoHS Call TI | SN Level-1-NA-UNLIM -40 to 125 LM2574N & no Sb/Br) -5.0 P+ LM2574N-ADJ/NOPB ACTIVE PDIP P 8 40 Green (RoHS SN Level-1-NA-UNLIM -40 to 125 LM2574N & no Sb/Br) -ADJ P+ (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. Addendum-Page 2

PACKAGE OPTION ADDENDUM www.ti.com 7-Feb-2020 (2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 3

PACKAGE MATERIALS INFORMATION www.ti.com 29-Sep-2019 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1(mm) LM2574HVMX-12/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574HVMX-15/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574HVMX-3.3/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574HVMX-5.0 SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574HVMX-5.0/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574HVMX-ADJ/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574MX-12/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574MX-3.3/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574MX-5.0/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 LM2574MX-ADJ/NOPB SOIC NPA 14 1000 330.0 16.4 10.9 9.5 3.2 12.0 16.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 29-Sep-2019 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) LM2574HVMX-12/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574HVMX-15/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574HVMX-3.3/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574HVMX-5.0 SOIC NPA 14 1000 367.0 367.0 38.0 LM2574HVMX-5.0/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574HVMX-ADJ/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574MX-12/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574MX-3.3/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574MX-5.0/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 LM2574MX-ADJ/NOPB SOIC NPA 14 1000 367.0 367.0 38.0 PackMaterials-Page2

MECHANICAL DATA NPA0014B www.ti.com

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