LM5002MA/NOPB

LM5002 High Voltage Switch Mode Regulator (Rev. D)

Document overview

• Manufacturer or author: Texas Instruments, Incorporated [SNVS496,D]
• PDF pages: 24

Technical content

+12V to +36V +48V LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 LM5002HighVoltageSwitchModeRegulator Check forSamples: LM5002 1FEATURES DESCRIPTION The LM5002 high voltageswitch mode regulator 2• Integrated75 VoltN-Channel MOSFET featuresallof the functionsnecessaryto implement• Ultra-WideInputVoltageRange from 3.1Vto efficienthigh voltageBoost, Flyback,SEPIC and75V Forward converters,usingfew externalcomponents.

• IntegratedHigh VoltageBias Regulator This easy to use regulatorintegratesa 75 VoltN- Channel MOSFET witha 0.5Amp peak currentlimit.• AdjustableOutput Voltage Currentmode controlprovidesinherentlysimpleloop• 1.5% Output VoltageAccuracy compensation and line-voltagefeed-forwardfor
• CurrentMode ControlwithSelectable superiorrejectionof inputtransients.The switching Compensation frequency is set with a singleresistorand is programmable up to1.5MHz. The oscillatorcan also• Wide Bandwidth ErrorAmplifier be synchronizedto an externalclock.Additional• IntegratedCurrentSensing and Limiting protectionfeaturesinclude:currentlimit,thermal
• IntegratedSlope Compensation shutdown, under-voltage lockout and remote shutdown capability.The deviceisavailableinboth• 85% Maximum Duty Cycle Limit SOIC-8 and WSON-8 packages.• SingleResistorOscillatorProgramming
• OscillatorSynchronizationCapability Packages
• Enable /UndervoltageLockout (UVLO) Pin • SOIC-8
• Thermal Shutdown • WSON-8 (4mm x 4mm) TypicalApplicationCircuit Figure1. Boost RegulatorApplicationSchematic Pleasebe aware thatan importantnoticeconcerningavailability,standardwarranty,and use incriticalapplicationsof Texas Instrumentssemiconductorproductsand disclaimerstheretoappearsattheend ofthisdatasheet. 2Alltrademarksarethepropertyoftheirrespectiveowners. PRODUCTION DATA informationiscurrentas ofpublicationdate. Copyright© 2007–2013,Texas InstrumentsIncorporatedProductsconform to specificationsper the terms of the Texas Instrumentsstandardwarranty.Productionprocessingdoes not necessarilyincludetestingofallparameters.

SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com Connection Diagram Figure2. SOIC-8 Package Figure3. WSON-8 Package Top View Top View PIN DESCRIPTIONS Pin Name Description ApplicationInformation SOIC WSON 1 3 SW Switchpin The drainterminaloftheinternalpower MOSFET. 2 4 VIN Inputsupplypin Nominaloperatingrange:3.1Vto75V. VCC tracksVIN up to6.9V.Above VIN = 6.9V,VCC is regulatedto6.9Volts.A 0.47µF orgreaterceramic Biasregulatoroutput,orinputforexternal decouplingcapacitorisrequired.An externalvoltage(7V –3 5 VCC biassupply 12V) can be appliedtothispinwhichdisablestheinternal VCC regulatortoreduceinternalpower dissipationand improveconverterefficiency. Internalreferencefortheregulatorcontrolfunctionsand the4 6 GND Ground power MOSFET currentsense resistorconnection. The internaloscillatorissetwitha resistor,between thispin and theGND pin.The recommended frequencyrangeis Oscillatorfrequencyprogrammingand 50KHz to1.5MHz. The RT pincan acceptsynchronization5 7 RT optionalsynchronizationpulseinput pulsesfroman externalclock.A 100 pF capacitoris recommended forcouplingthesynchronizingclocktothe RT pin. ThispinisconnectedtotheinvertinginputoftheinternalFeedback inputfromtheregulatedoutput6 8 FB erroramplifier.The 1.26Vreferenceisinternallyconnectedvoltage tothenon-invertinginputoftheerroramplifier. The loopcompensationnetworkshouldbe connected between theCOMP pinand theFB pin.COMP pull-upisOpen drainoutputoftheinternalerror7 1 COMP providedby an internal5 kΩ resistorwhichmay be used toamplifier biasan opto-couplertransistor(whileFB isgrounded)for isolatedgroundapplications. An externalvoltagedividercan be used tosettheline Enable/Under VoltageLock-Out/ undervoltagelockoutthreshold.IftheEN pinisleft8 2 EN Shutdown input unconnected,a 6 µA pull-upcurrentsourcepullstheEN pin hightoenabletheregulator. Exposed metalpad on theundersideofthepackage witha resistiveconnectiontopin6.Itisrecommended toconnectNA EP EP Exposed Pad,WSON only thispad tothePC boardgroundplaneinordertoimprove heatdissipation. These deviceshave limitedbuilt-inESD protection.The leadsshouldbe shortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamage totheMOS gates.

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www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 AbsoluteMaximum Ratings(1)(2) VIN toGND 76V SW toGND (SteadyState) -0.3Vto76V VCC, EN toGND 14V COMP, FB, RT toGND -0.3Vto7V Maximum JunctionTemperature 150°C StorageTemperature −65°C to+150°C ESD Rating(3) Human Body Model 2kV (1) Absolutemaximum ratingsarelimitsbeyond whichdamage tothedevicemay occur.OperatingRatingsareconditionsforwhichthe deviceisintendedtobe functional,butdeviceparameterspecificationsmay notbe ensured.Forensuredspecificationsand test conditions,see theElectricalCharacteristics. (2) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTexas InstrumentsSalesOffice/Distributorsforavailabilityand specifications. (3) The human body model isa 100 pF capacitordischargedthrougha 1.5kΩ resistorintoeach pin.TestMethod isperJESD-22-A114. OperatingConditions VIN 3.1Vto75V OperatingJunctionTemperature −40°C to+125°C ElectricalCharacteristics LimitsinstandardtypeareforTJ = 25°C only;limitsinboldfacetypeapplyoverthejunctiontemperature(TJ)rangeof-40°C to+125°C. Minimum and Maximum limitsareensuredthroughtest,design,orstatisticalcorrelation.Typicalvaluesrepresent themost likelyparametricnorm atTJ = 25°C, and areprovidedforreferencepurposesonly.VVIN = 10V,R RT = 48.7kΩ unless otherwisestated(1). Symbol Parameter Conditions Min Typ Max Units STARTUP REGULATOR VVCC-REG VCC RegulatorOutput 6.55 6.85 7.15 V VCC CurrentLimit VVCC = 6V 15 20 mA VCC UVLO Threshold VVCC increasing 2.6 2.8 3 V VCC UndervoltageHysteresis 0.1 V BiasCurrent(IIN) VFB = 1.5V 3.1 4.5 mA IQ Shutdown Current(IIN) VEN = 0V 95 130 µA EN THRESHOLDS EN Shutdown Threshold VEN increasing 0.25 0.45 0.65 V EN Shutdown Hysteresis 0.1 V EN StandbyThreshold VEN increasing 1.2 1.26 1.32 V EN StandbyHysteresis 0.1 V EN CurrentSource 6 µA MOSFET CHARACTERISTICS MOSFET R DS(ON) plus ID = 0.25A 850 1600 m ΩCurrentSense Resistance MOSFET Leakage Current VSW = 75V 0.05 5 µA MOSFET Gate Charge VVCC = 6.9V 2.4 nC CURRENT LIMIT ILIM Cycleby CycleCurrentLimit 0.4 0.5 0.6 A Cycleby CycleCurrentLimitDelay 100 200 ns (1) Min and Max limitsare100% productiontestedat25°C. Limitsovertheoperatingtemperaturerangeareensuredthroughcorrelation usingStatisticalQualityControl(SQC) methods.Limitsareused tocalculateTI’s AverageOutgoingQualityLevel(AOQL). Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LM5002

SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com ElectricalCharacteristics(continued) LimitsinstandardtypeareforTJ = 25°C only;limitsinboldfacetypeapplyoverthejunctiontemperature(TJ)rangeof-40°C to+125°C. Minimum and Maximum limitsareensuredthroughtest,design,orstatisticalcorrelation.Typicalvaluesrepresent themost likelyparametricnorm atTJ = 25°C, and areprovidedforreferencepurposesonly.VVIN = 10V,R RT = 48.7kΩ unless otherwisestated(1). Symbol Parameter Conditions Min Typ Max Units OSCILLATOR FSW1 Frequency1 R RT = 48.7kΩ 225 260 295 KHz FSW2 Frequency2 R RT = 15.8kΩ 660 780 900 KHz VRT-SYNC SYNC Threshold 2.2 2.6 3.2 V SYNC PulseWidthMinimum VRT > VRT-SYNC + 0.5V 15 ns PWM COMPARATOR Maximum DutyCycle 80 85 90 % Min On-time VCOMP > VCOMP-OS 25 ns Min On-time VCOMP < VCOMP-OS 0 ns VCOMP-OS COMP toPWM ComparatorOffset 0.9 1.30 1.55 V ERROR AMPLIFIER VFB-REF InternalreferenceFeedback ReferenceVoltage 1.241 1.260 1.279 VVFB = VCOMP FB BiasCurrent 10 nA DC Gain 72 dB COMP SinkCurrent VCOMP = 250mV 2.5 mA COMP ShortCircuitCurrent VFB = 0,VCOMP = 0 0.9 1.2 1.5 mA COMP Open CircuitVoltage VFB = 0 4.8 5.5 6.2 V COMP toSW Delay 42 ns UnityGain Bandwidth 3 MHz THERMAL SHUTDOWN TSD ThermalShutdown Threshold 165 °C ThermalShutdown Hysteresis 20 °C THERMAL RESISTANCE θJC JunctiontoCase,SOIC-8 32 °C/W θJA JunctiontoAmbient,SOIC-8 140 °C/W θJC JunctiontoCase,WSON-8 4.5 °C/W θJA JunctiontoAmbient,WSON-8 40 °C/W

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www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 TypicalPerformance Characteristics Efficiency,Boost Converter VFB vs Temperature Figure4. Figure5. IQ (non-switching)vs VIN VCC vs VIN Figure6. Figure7. R DS(ON) vs VCC R DS(ON) vs Temperature Figure8. Figure9. Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LM5002

SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com TypicalPerformance Characteristics(continued) ILIM vs VCC ILIM vs VCC vs Temperature Figure10. Figure11. FSW vs R RT FSW vs Temperature Figure12. Figure13. FSW vs VCC IEN vs VVIN vs Temperature Figure14. Figure15.

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(Leading Edge Blanking) RAMP S R Q VCC ENABLE ENABLE Disable VCCENABLE CSCS RAMP CS SLOPE COMP RAMP 450 mV Disable ENABLE CLK CURRENT LIMIT 1.5V 1.3V +5V 1.26V CURRENT SENSE 100 m: 1.26V +5V +6.9V 2.8V 0.45V6 PA REFERENCE GENERATOR Av = 30 0.7 THERMAL STANDBY (165oC) OSCILLATOR WITH SYNC CAPABILITY 1.26V LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 Block Diagram FUNCTIONAL DESCRIPTION The LM5002 highvoltageswitchingregulatorfeaturesallthefunctionsnecessarytoimplementan efficientboost, flyback,SEPIC orforwardcurrentmode power converter.The operationcan be bestunderstoodby referringto theblockdiagram.At thestartofeach cycle,theoscillatorsetsthedriverlogicand turnson thepower MOSFET to conductcurrentthroughthe inductoror transformer.The peak currentinthe MOSFET iscontrolledby the voltageattheCOMP pin.The COMP voltagewillincreasewithlargerloadsand decreasewithsmallerloads. Thisvoltageiscompared withthesum ofa voltageproportionaltothepower MOSFET currentand an internally generatedSlope Compensation ramp. Slope Compensation is used in currentmode PWM architecturesto eliminatesub-harmoniccurrentoscillationthatoccurs withstaticduty cyclesgreaterthan 50%. When the summed signalexceeds theCOMP voltage,thePWM comparatorresetsthedriverlogic,turningoffthepower MOSFET. The driverlogicisthensetby theoscillatorattheend oftheswitchingcycletoinitiatethenextpower period. Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LM5002

RT = 13.1 x 109 x FSW - 83 ns LM5002 SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com The LM5002 has dedicatedprotectioncircuitrytoprotecttheIC from abnormaloperatingconditions.Cycle-by- cyclecurrentlimitingpreventsthepower MOSFET currentfromexceeding0.5A.Thisfeaturecan alsobe used to soft-startthe regulator.Thermal Shutdown circuitryholdsthe driverlogicin resetwhen the die temperature reaches165°C, and returnstonormaloperationwhen thedietemperaturedropsby approximately20°C. The EN pincan be used as an inputvoltageundervoltagelockout(UVLO) duringstart-uptopreventoperationwithless thantheminimum desiredinputvoltage. High VoltageVCC Regulator The LM5002 VCC Low Drop Out (LDO) regulatorallowsthe LM5002 to operateat the lowestpossibleinput voltage.The VCC pinvoltageisverynearlyequaltotheinputvoltagefrom 2.8V up toapproximately6.9V.As theinputvoltagecontinuestoincrease,theVCC pinvoltageisregulatedatthe6.9V set-point.The totalinput operatingrangeoftheVCC LDO regulatoris3.1Vto75V. The outputoftheVCC regulatoriscurrentlimitedto20mA. Duringpower-up,theVCC regulatorsuppliescurrent intotherequireddecouplingcapacitor(0.47µF orgreaterceramiccapacitor)attheVCC pin.When thevoltageat theVCC pinexceeds theVCC UVLO thresholdof2.8V and theEN pinisgreaterthan1.26V thePWM controller isenabledand switchingbegins.The controllerremainsenableduntilVCC fallsbelow 2.7V or theEN pinfalls below1.16V. An auxiliarysupplyvoltagecan be appliedto the VCC pinto reduce the IC power dissipation.Ifthe auxiliary voltageisgreaterthan6.9V,theinternalregulatorwillessentiallyshut-off,and internalpower dissipationwillbe decreasedby theVIN voltagetimestheoperatingcurrent.The overallconverterefficiencywillalsoimproveifthe VIN voltageismuch higherthan the auxiliaryvoltage.The externallyappliedVCC voltageshouldnot exceed 14V. The VCC regulatorseriespass MOSFET includesa body diode(seetheBlockDiagram)between VCC and VIN thatshouldnotbe forwardbiasedinnormaloperation.Therefore,theauxiliaryVCC voltageshouldnever exceed theVIN voltage. In highvoltageapplicationsextracare shouldbe takento ensure the VIN pindoes not exceed the absolute maximum voltageratingof76V. Voltageringingon theVIN lineduringlinetransientsthatexceeds theAbsolute Maximum Ratingswilldamage the IC.Both carefulPC board layoutand the use of qualitybypass capacitors locatedclosetotheVIN and GND pinsareessential. Oscillator A singleexternalresistorconnectedbetween RT and GND pinssetstheLM5002 oscillatorfrequency.To seta desiredoscillatorfrequency(FSW ),thenecessaryvaluefortheRT resistorcan be calculatedfrom thefollowing equation: (1) The toleranceoftheexternalresistorand thefrequencytoleranceindicatedintheElectricalCharacteristicsmust be takenintoaccountwhen determiningtheworstcase frequencyrange. ExternalSynchronization The LM5002 can be synchronizedtotherisingedge ofan externalclock.The externalclockmust have a higher frequencythanthefreerunningoscillatorfrequencysetby theRT resistor.The clocksignalshouldbe coupled througha 100pF capacitorintotheRT pin.A peak voltagelevelgreaterthan2.6V attheRT pinisrequiredfor detectionof the sync pulse.The DC voltageacrossthe RT resistorisinternallyregulatedat 1.5 volts.The negativeportionoftheAC voltageofthesynchronizingclockisclamped tothis1.5V by an amplifierinsidethe LM5002 with~100Ω outputimpedance.Therefore,the AC pulsesuperimposedon the RT resistormust have positivepulseamplitudeof 1.1V or greaterto successfullysynchronizethe oscillator.The sync pulsewidth measured attheRT pinshouldhave a durationgreaterthan15ns and lessthan5% oftheswitchingperiod.The sync pulserisingedge initiatestheinternalCLK signalrisingedge,whichturnsoffthepower MOSFET. The RT resistorisalways required,whetherthe oscillatorisfreerunningor externallysynchronized.The RT resistor shouldbe locatedveryclosetothedeviceand connecteddirectlytotheRT and GND pinsoftheLM5002.

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1.3V 1.26V FDC_POLE = FPOLE = FZERO = 2S x R1 x(C1 + C2) C 1 xC 2 2S x R2 xC 2 2S x R2 x C 1 + C2 LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 Enable /Standby The LM5002 containsa duallevelEnable circuit.When theEN pinvoltageisbelow 450 mV, theIC isina low currentshutdown mode withthe VCC LDO disabled.When the EN pinvoltageisraisedabove the shutdown thresholdbutbelow the1.26V standbythreshold,theVCC LDO regulatorisenabled,whiletheremainderofthe IC isdisabled.When theEN pinvoltageisraisedabove the1.26V standbythreshold,allfunctionsareenabled and normaloperationbegins.An internal6 µA currentsourcepullsup theEN pintoactivatetheIC when theEN pinisleftdisconnected. An externalset-pointresistordividerfrom VIN toGND can be used todeterminetheminimum operatinginput rangeoftheregulator.The dividermust be designedsuch thattheEN pinexceeds the1.26V standbythreshold when VIN is in the desiredoperatingrange.The internal6 µA currentsource should be includedwhen determiningtheresistorvalues.The shutdown and standbythresholdshave 100 mV hysteresistopreventnoise from togglingbetween modes. When the VIN voltageis below 3.5VDC duringstart-upand the operating temperatureisbelow -20°C, theEN pinshouldhave a pull-upresistorthatwillprovide2 µA or greatercurrent. The EN pinisinternallyprotectedby a 6V Zenerdiodethrougha 1 kΩ resistor.The enablingvoltagemay exceed theZenervoltage,however theZenercurrentshouldbe limitedtolessthan4mA. ErrorAmplifierand PWM Comparator An internalhigh gain erroramplifiergeneratesan errorsignalproportionalto the differencebetween the regulatedoutputvoltageand an internalprecisionreference.The outputoftheerroramplifierisconnectedtothe COMP pinallowingtheusertoadd loopcompensation,typicallya Type IInetwork,as illustratedinFigure16. Thisnetworkcreatesa low frequencypolethatrollsoffthehighDC gainoftheamplifier,whichisnecessaryto accuratelyregulatetheoutputvoltage.FDC_POLE istheclosedloopunitygain(0dB) frequencyofthispole.A zero providesphase boostneartheclosedloopunitygainfrequency,and a highfrequencypoleattenuatesswitching noise.The PWM comparatorcompares the currentsense signalfrom the currentsense amplifierto the error amplifieroutputvoltageattheCOMP pin. Figure16. Type IICompensator When isolationbetween primaryand secondarycircuitsisrequired,the ErrorAmplifierisusuallydisabledby connectingtheFB pintoGND. ThisallowstheCOMP pintobe drivendirectlyby thecollectorofan opto-coupler. In isolateddesignsthe externalerroramplifierislocatedon the secondarycircuitand drivesthe opto-coupler LED. The compensationnetworkisconnectedtothesecondarysideerroramplifier.An example ofan isolated regulatorwithan opto-couplerisshown inFigure22. Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LM5002

SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com CurrentAmplifierand Slope Compensation The LM5002 employs peak currentmode controlwhich alsoprovidesa cycle-by-cycleover currentprotection feature.An internal100 m Ω currentsense resistormeasures the currentinthe power MOSFET source.The sense resistorvoltageisamplified30 timestoprovidea 3V/A signalintothecurrentlimitcomparator.Current limitingisinitiatedifthe internalcurrentlimitcomparatorinputexceeds the 1.5V threshold,correspondingto 0.5A. When the currentlimitcomparatoris triggered,the SW outputpin immediatelyswitchesto a high impedance state. The currentsense signalisreducedtoa scalefactorof2.1V/AforthePWM comparatorsignal.The signalis then summed with a 450mV peak slope compensation ramp. The combined signalprovidesthe PWM comparatorwitha controlsignalthatreaches1.5V when theMOSFET currentis0.5A.For dutycyclesgreater than 50%, currentmode controlcircuitsare subjectto sub-harmonicoscillation(alternatingbetween shortand long PWM pulsesevery othercycle).Adding a fixedslopevoltageramp signal(slopecompensation)to the currentsense signalpreventsthisoscillation.The 450mV ramp (zerovoltswhen thepower MOSFET turnson, and 450mV at the end of the PWM clockcycle)adds a fixedslopeto the currentsense ramp to prevent oscillation. To preventerraticoperationatlow dutycycle,a leadingedge blankingcircuitattenuatesthecurrentsense signal when thepower MOSFET isturnedon.When theMOSFET isinitiallyturnedon,currentspikesfromthepower MOSFET drain-sourceand gate-sourcecapacitancesflowthroughthe currentsense resistor.These transient currentsnormallycease within50 ns withproperselectionofrectifierdiodesand properPC boardlayout. Thermal Protection InternalThermalShutdown circuitryisprovidedtoprotecttheIC intheeventthemaximum junctiontemperature isexceeded.When the165°C junctiontemperaturethresholdisreached,theregulatorisforcedintoa low power standbystate,disablingallfunctionsexcepttheVCC regulator.Thermal hysteresisallowstheIC tocooldown beforeitisre-enabled.Note thatsincethe VCC regulatorremainsfunctionalduringthisperiod,the soft-start circuitshown inFigure20 shouldbe augmented ifsoft-startfromThermalShutdown stateisrequired. Power MOSFET The LM5002 switchingregulatorincludesan N-ChannelMOSFET with850 m Ω on-resistance.The on-resistance of the LM5002 MOSFET varieswithtemperatureas shown inthe TypicalPerformanceCharacteristicsgraph. The typicaltotalgatechargefortheMOSFET is2.4nC whichissuppliedfromtheVCC pinwhen theMOSFET is turnedon.

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0.1 PF LM5002 LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013

APPLICATION INFORMATION

The followinginformationisintendedtoprovideguidelinesforthepower supplydesignerusingtheLM5002. VIN The voltageappliedto the VIN pin can vary withinthe range of 3.1V to 75V. The currentintothe VIN pin depends primarilyon thegatechargeofthepower MOSFET, theswitchingfrequency,and any externalloadon theVCC pin.Itisrecommended thefiltershown inFigure17 be used tosuppresstransientswhichmay occurat theinputsupply.Thisisparticularlyimportantwhen VIN isoperatedclosetothemaximum operatingratingofthe LM5002. When power isappliedand theVIN voltageexceeds 2.8V withtheEN pinvoltagegreaterthan0.45V,theVCC regulatorisenabled,supplyingcurrentintothe externalcapacitorconnectedto the VCC pin.When the VIN voltageisbetween 2.8V and 6.9V,theVCC voltageisapproximatelyequaltotheVIN voltage.When thevoltage on the VCC pin exceeds 6.9V,the VCC pin voltageisregulatedat 6.9V.In typicalflybackapplications,an auxiliarytransformerwindingisconnectedthrougha diodeto the VCC pin.Thiswindingmust raisethe VCC voltageabove 6.9V to shutoffthe internalstart-upregulator.The currentrequirementsfrom thiswindingare relativelysmall,typicallylessthan 20 mA. Ifthe VIN voltageismuch higherthan the auxiliaryvoltage,the auxiliarywindingwillsignificantlyimproveconversionefficiency.Italsoreducesthepower dissipationwithinthe LM5002. The externallyappliedVCC voltageshouldnever exceed 14V. Also the appliedVCC shouldnever exceed theVIN voltagetoavoidreversecurrentthroughtheinternalVCC toVIN diodeshown intheLM5002 BlockDiagram. Figure17. InputTransientProtection SW PIN Attentionmust be givento the PC board layoutforthe SW pinwhich connectsto the power MOSFET drain. Energycan be storedinparasiticinductanceand capacitancewhichcause switchingspikesthatnegativelyeffect efficiency,and conductedand radiatedemissions.These connectionsshouldbe as shortas possibletoreduce inductanceand as wide as possibleto reduce resistance.The loop area,definedby the SW and GND pin connections,thetransformerorinductorterminals,and theirrespectivereturnpaths,shouldbe minimized. EN /UVLO VOLTAGE DIVIDER SELECTION Two dedicatedcomparatorsconnectedtotheEN pinareused todetectunder-voltageand shutdown conditions. When theEN pinvoltageisbelow 0.45V,thecontrollerisina low currentshutdown mode where theVIN current isreducedto95 µA. For an EN pinvoltagegreaterthan0.45V butlessthan1.26V thecontrollerisinstandby mode, withallinternalcircuitsoperational,butthePWM gatedriversignalisblocked.Once theEN pinvoltageis greaterthan1.26V,thecontrollerisfullyenabled.Two externalresistorscan be used toprogram theminimum operationalvoltageforthe power converteras shown inFigure18. When the EN pinvoltagefallsbelow the 1.26V threshold,an internal100 mV thresholdhysteresispreventsnoisefrom togglingthestate,so thevoltage must be reducedto1.16V totransitiontostandby.ResistancevaluesforR1 and R2 can be determinedfromthe followingequations: Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LM5002

1.26V 0.45V EN LM5002 Disable PWM Controller Disable VCC Regulator VIN 1.26V 0.45V 6 PA VPWR R2 = 1.26V IDIVIDER + 6 PA R1 = VPWR - 1.26V IDIVIDER LM5002 SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com (2) where

• VPWR isthedesiredturn-onvoltage
• IDIVIDER isan arbitrarycurrentthroughR1 and R2 (3) For example,iftheLM5002 istobe enabledwhen VPWR reaches16V, IDIVIDER couldbe chosen as 501 µA which would setR1 to29.4kΩ and R2 to2.49kΩ.The voltageattheEN pinshouldnotexceed 10V unlessthecurrent intothe6V protectionZener diodeislimitedbelow 4 mA. The EN pinvoltageshouldnotexceed 14V atany time. Be sure to check both the power and voltagerating(some 0603 resistorsare ratedas low as 50V) forthe selectedR1 resistor. Figure18. Basic EN (UVLO) Configuration Remote configurationof the controller’s operationalmodes can be accomplishedwithopen draindevice(s) connectedtotheEN pinas shown inFigure19.A MOSFET oran NPN transistorconnectedtotheEN pincan forcetheregulatorintothelow power ‘off’state.Addinga PN diodeinthedrain(orcollector)providestheoffset to achievethe standbystate.The advantage of standbyisthatthe VCC LDO isnot disabledand external circuitrypowered by VCC remainsfunctional. Figure19. Remote Standby and DisableControl

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1.3V 1.26V LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 SOFTSTART Soft-start(SS)can be implementedwithan externalcapacitorconnectedtoCOMP througha diodeas shown in Figure20.The COMP dischargeMOSFET conductsduringShutdown and Standby modes tokeep theCOMP voltagebelow the PWM offset(1.3V),which inhibitsPWM pulses.The erroramplifierwillattemptto raisethe COMP voltageafterthe EN pinexceeds the 1.26V standbythreshold.Because the erroramplifieroutputcan onlysinkcurrent,theinternalCOMP pull-upresistor(~5kΩ)willsupplythechargingcurrenttotheSS capacitor. The SS capacitorwillcause theCOMP voltagetograduallyincrease,untiltheoutputvoltageachievesregulation and FB assumes controloftheCOMP and thePWM dutycycle.The SS capacitorcontinueschargingthrougha largeresistance,R SS ,preventingtheSS circuitfrom interferingwiththenormalerroramplifierfunction.During shutdown,theVCC diodedischargestheSS capacitor. Figure20. Soft-Start PrintedCircuitBoard Layout The LM5002 CurrentSense and PWM comparatorsare very fastand may respond to shortdurationnoise pulses.The components attheSW, COMP, EN and theRT pinsshouldbe as physicallycloseas possibletothe IC,therebyminimizingnoisepickupon thePC boardtracks. The SW outputpinoftheLM5002 shouldhave a short,wide conductortothepower pathinductors,transformers and capacitorsinorderto minimizeparasiticinductancethatreducesefficiencyand increasesconductedand radiatednoise.Ceramic decouplingcapacitorsare recommended between the VIN pin to the GND pin and between theVCC pintotheGND pin.Use short,directconnectionstoavoidclockjitterdue toground voltage differentials.Smallpackage surfacemount X7R orX5R capacitorsarepreferredforhighfrequencyperformance and limitedvariationovertemperatureand appliedvoltage. Ifan applicationusingtheLM5002 produceshighjunctiontemperaturesduringnormaloperation,multiplevias fromtheGND pintoa PC boardgroundplanewillhelpconductheataway fromtheIC.Judiciouspositioningof the PC board withinthe end product,along withuse of any availableairflowwillhelp reduce the junction temperatures.Ifusingforcedaircooling,avoidplacingtheLM5002 intheairflowshadow oflargecomponents, such as inputcapacitors,inductorsortransformers. Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LM5002

SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com ApplicationCircuitExamples The followingschematicspresentexamples ofa Non-IsolatedFlyback,IsolatedFlyback,Boost,24V SEPIC and a 12V AutomotiverangeSEPIC convertersutilizingtheLM5002 switchingregulator. NON-ISOLATED FLYBACK The Non-IsolatedFlybackconverter(Figure21)utilizestheinternalvoltagereferencefortheregulationsetpoint. The outputis+5V at500mA whiletheinputvoltagecan varyfrom16V to42V. The switchingfrequencyissetto 250kHz. An auxiliarywindingon transformer(T1)provides7.5V to power the LM5002 when the outputisin regulation.ThisdisablestheinternalhighvoltageVCC LDO regulatorand improvesefficiency.The inputunder- voltagethresholdis13.9V.The convertercan be shutdown by drivingtheEN inputbelow 1.26V withan open- collectoror open-draintransistor.An externalsynchronizingfrequencycan be appliedto the SYNC input.An optionalsoft-startcircuitisconnectedtotheCOMP pininput.When power isapplied,thesoft-startcapacitor(C7) isdischargedand limitsthevoltageappliedtothePWM comparatorby theinternalerroramplifier.The internal ~5 kΩ COMP pull-upresistorcharges the soft-startcapacitoruntilregulationisachieved.The VCC pull-up resistor(R7) continuesto charge C7 so thatthe soft-startcircuitwillnot affectthe compensationnetworkin normaloperation.Iftheoutputcapacitanceissmall,thesoft-startcircuitcan be adjustedtolimitthepower-on outputvoltageovershoot.Iftheoutputcapacitanceissufficientlylarge,no soft-startcircuitisneeded because the LM5002 willgraduallycharge the outputcapacitorby currentlimitingat approximately500mA (ILIM) until regulationisachieved. ISOLATED FLYBACK The IsolatedFlybackconverter(Figure22) utilizesa 2.5V voltagereference(LM431) locatedon the isolated secondarysidefortheregulationsetpoint.The LM5002 internalerroramplifierisdisabledby groundingtheFB pin.The LM431 controlsthecurrentthroughtheopto-couplerLED, which setstheCOMP pinvoltage.The R4 and C3 networkbooststhephase responseoftheopto-couplertoincreasetheloopbandwidth.The outputis +5V at500mA and theinputvoltagerangesfrom16V to42V.The switchingfrequencyissetto250kHz. BOOST The Boost converter(Figure23) utilizestheinternalvoltagereferencefortheregulationsetpoint.The outputis +48V at125 mA, whiletheinputvoltagecan varyfrom 16V to36V. The switchingfrequencyissetto250kHz. The internalVCC regulatorprovides6.9V biaspower,sincethereisn’ta simplemethod forcreatingan auxiliary voltagewiththe boosttopology.Note thatthe boosttopologydoes not provideoutputshort-circuitprotection because thepower MOSFET cannotinterruptthepathbetween theinputand theoutput. 24V SEPIC The 24V SEPIC converter(Figure24) utilizesthe internalvoltagereferenceforthe regulationsetpoint.The outputis+24V at125 mA whiletheinputvoltagecan varyfrom 16V to48V. The switchingfrequencyissetto 250kHz. The internalVCC regulatorprovides6.9V biaspower forthe LM5002. An auxiliaryvoltagecan be createdby addinga windingon L2 and a diodeintotheVCC pin. 12V AUTOMOTIVE SEPIC The 12V AutomotiveSEPIC converter(Figure25) utilizesthe internalbandgap voltagereferenceforthe regulationsetpoint.The outputis+12V at25 mA whiletheinputvoltagecan varyfrom3.1V to60V. The output currentratingcan be increasediftheminimum VIN voltagerequirementisincreased.The switchingfrequencyis setto750kHz.The internalVCC regulatorprovides6.9V biaspower fortheLM5002. The outputvoltagecan be used as an auxiliaryvoltageifthenominalVIN voltageisgreaterthan12V by addinga diodefromtheoutputinto theVCC pin.Inthisconfiguration,theminimum inputvoltagemust be greaterthan12V topreventtheinternal VCC to VIN diode from conducting.Ifthe appliedVCC voltageexceeds the minimum VIN voltage,then an externalblockingdiodeisrequiredbetween theVIN pinand thepower sourcetoblockcurrentflowfromVCC to theinputsupply.

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VIN = 16V ± 36V VOUT = 48V IOUT = 125 mAC1 4.7 PF 1 PF 10 PF 2200 pF 60.4k 6.04k 52.3k 73.2k 54.9k 1.47k 330 PH LM5002 VIN RT EN GND SW FB COMP VCC VIN = 16V ± 42V VOUT = 5V IOUT = 500mA LPRI = 160 éH 8:3:2 4.7 éF VCC VCC 100éF 60.4k 6.04k 52.3k LM431 4.99k 0.1 PF 1 éF 1 éF R10 2.20k 2.20kR4 249 10k 1 éF 560 LM5002 VIN RT EN GND SW FB COMP VCC VIN = 16V ± 42V VOUT = 5V IOUT = 500 mA LPRI = 160 PH 8:3:2 4.7 PF 1 PF VCC VCC 100 PF 220 pF 4700 pF 60.4k 6.04k 52.3k 13.0k 10.2k 3.40k EN SYNC 100 pF 10 PF 100k LM5002 www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013 Figure21. Non-IsolatedFlyback Figure22. IsolatedFlyback Figure23. Boost Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LM5002

VIN = 3.1V ± 60V VOUT = 12V IOUT = 25 mAC1 2.2 PF 1 PF 22 éF 0.015 PF 15.8k 11.5k 11.5k 1.33k 100 PH 100 PH 4.7 PF 150 pF NC LM5002 VIN RT EN GND SW FB COMP VCC VIN = 16V ± 48V VOUT = 24V IOUT = 125 mAC1 4.7 PF 1 PF 22éF 0.015 PF 60.4k 6.04k 52.3k 11.5k 11.5k 634 470 PH 470 PH 10 PF 150 pF LM5002 SNVS496D –JANUARY 2007–REVISED MARCH 2013 www.ti.com Figure24. 24V SEPIC Figure25. 12V SEPIC

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www.ti.com SNVS496D –JANUARY 2007–REVISED MARCH 2013

REVISION HISTORY

Changes from RevisionC (March 2013)toRevisionD Page Copyright© 2007–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LM5002

www.ti.com 14-Feb-2014 Addendum-Page 1 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/Ball Finish (6) MSL Peak Temp (3) Op Temp (°C) Device Marking (4/5) Samples LM5002MA/NOPB ACTIVE SOIC D 8 95 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 L5002 MA LM5002MAX NRND SOIC D 8 2500 TBD Call TI Call TI -40 to 125 L5002 MA LM5002MAX/NOPB ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 L5002 MA LM5002SD/NOPB ACTIVE WSON NGT 8 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM5002 LM5002SDX/NOPB ACTIVE WSON NGT 8 4500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM5002 (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. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (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.

www.ti.com 14-Feb-2014 Addendum-Page 2 (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.

*All dimensions are nominal Device Package Type Package Drawing Pins SPQ Reel Diameter (mm) Reel Width W1 (mm) (mm) (mm) (mm) (mm) W (mm) Pin1 Quadrant PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 Pack Materials-Page 1

*All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM5002MAX SOIC D 8 2500 367.0 367.0 35.0 LM5002MAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LM5002SD/NOPB WSON NGT 8 1000 210.0 185.0 35.0 LM5002SDX/NOPB WSON NGT 8 4500 367.0 367.0 35.0 PACKAGE MATERIALS INFORMATION www.ti.com 11-Oct-2013 Pack Materials-Page 2

www.ti.com SDC08A (Rev A)

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