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1 %IOutput Current AO--Efficiency vs Output CurrentSimplified Schematic25055657585VI= 12 APRIL2006 REVISEDSEPTEMBER20132-A, WIDE INPUTRANGE, step -DOWNCONVERTERC heckfor Samples:TPS54201 FEATURESAPPLICATIONS V to 36 V Consumer:Set-topBox,DVD,LCDD isplays Up to 2-A Continuous(3-APeak)Output Industrialand Car AudioPowerSuppliesCurrent BatteryChargers,HighPowerLEDS upply HighEfficiencyup to 95%Enabledby 110-m 12-V/24-VDistributedPowerSystemsIntegrat edMOSFETS witch WideOutputVoltageRange:AdjustableDownDES CRIPTIONto a high-output-currentPWMconverterthat integratesa low resistancehighside the substratewithPartsCountthe listedfeaturesis a high performancevoltageerror Fixed500-kHzSwitchingFrequencyfor Smallamplifierthatprovidestightvoltagere gulationFilterSizeaccuracyundertransient conditions;an undervoltage- ImprovedLineRegulationand Transientlockoutcircuitto preventstart-upuntilthe V; an internallyset slow-startResponseby InputVoltageFeedForwardcircuitto limitinrushcurrents.

2 And a voltagefeed- SystemProtectedby OverCurrentLimiting,forwardcircuitto improvethe ThermalUsingthe ENApin,shutdownsupplycurrentisShutdownre ducedto 18 A 40 C to 125 C OperatingJunctionactive-highenable,overc urrentlimiting,overvoltageTemperatureRan geprotectionand reducedesigncomplexityandexternalcompone ntcount,the Availablein Small8-PinSOICP ackageTPS5420feedbackloop is TPS5420deviceis availablein an easyto use 8-pin providesevaluationmodulesandthe Designersoftwaretoolto aid in awarethat an importantnoticeconcerningavailability,st andardwarranty,and use in criticalapplicationsofTexasInstrumentsse miconductorproductsand disclaimerstheretoappearsat the end of this currentas of 2006 2013,TexasInstrumentsIncorporatedProduct sconformto specificationsper the termsof the all APRIL2006 leadsshouldbe shortedtogetheror the deviceplacedin conductivefoamduringstorageor handlingto preventelectrostaticdamageto the (1)PARTNUMBER 40 C to 125 V to 36 VAdjustableto (D)(2)TPS5420D(1)For the mostcurrentpackageand orderinginformation,see thePackageOptionAddendumat the end of this document,or see the TIweb site at (2)The D packageis availabletapedand an R suffixto the devicetype ( ,TPS5420DR).

3 ABSOLUTEMAXIMUMRATINGS overoperatingfree-airtemperaturerange(un lessotherwisenoted)(1) (2)VALUEUNITVIN to 40(3)BOOT to 50PH (steady-state) to 40(3)VIInputvoltagerangeEN to 7 VVSENSE to 3 BOOT-PH10PH (transient< 10 ns) ATJO peratingvirtualjunctiontemperaturerange 40 to 150 CTstgStoragetemperature 65 to 150 C(1)Stressesbeyondthoselistedunderabsolu temaximumratingsmay causepermanentdamageto the stressratingsonly and functionaloperationof the deviceat theseor any otherconditionsbeyondthoseindicatedunder recommendedoperatingconditionsis not absolute-maximum-ratedconditionsfor extendedperiodsmay affectdevicereliability.(2)All voltagevaluesare with respectto networkgroundterminal.(3)Approachingthe absolutemaximumratingfor the VIN pin may causethe voltageon the PH pin to exceedthe (1)(2)(3)UNITSD (8 PINS) JAJunction-to-ambientthermalresistance(c ustomboard)(4)75 JAJunction-to-ambientthermalresistance(s tandardboard) C/W JC(top)Junction-to-case(top) JC(bottom)Junction-to-case(bottom)therma lresistancen/a (1)For moreinformationabouttraditionaland new thermalmetrics,see the IC PackageThermalMetricsapplicationreport,S PRA953.

4 (2)Maximumpowerdissipationmay be limitedby overcurrentprotection(3)Powerratingat a specificambienttemperatureTAshouldbe determinedwith a junctiontemperatureof 125 C. This is the pointwheredistortionstartsto the final PCBshouldstriveto keepthe junctiontemperatureat orbelow125 C for best performanceand applicationssectionof this datasheetfor moreinformation.(4)Testboardsconditions: (a) 3 in x 3 in, 2 layers, (b) 2 oz. coppertraceslocatedon the top and bottomof the 2006 2013, APRIL2006 REVISEDSEPTEMBER2013 RECOMMENDEDOPERATINGCONDITIONSMINNOMMAXU NITVII nputvoltagerange, 40125 CELECTRICALCHARACTERISTICSTJ= 40 C to 125 C, VIN = V to 36 V (unlessotherwisenoted)PARAMETERTESTCONDI TIONSMINTYPMAXUNITSUPPLYVOLTAGE(VINPIN)V SENSE= 2 V, Not switching,PH ,ENA= 0 V1850 AUNDERVOLTAGELOCKOUT(UVLO)Startthreshold voltage, ,UVLO330mVVOLTAGEREFERENCETJ= 25 0 A 2 free-runningfrequency400500600kHzMinimum controllableon time150200nsMaximumduty cycle87%89%ENABLE(ENAPIN)Startthresholdv oltage, , ,ENA450mVInternalslow-starttime (0 ~ 100%)

5 Hiccuptime131620msTHERMALSHUTDOWNT hermalshutdowntrip point135162 CThermalshutdownhysteresis14 COUTPUTMOSFETVIN = V150rDS(on)Highside powerMOSFET switchm VIN = 10 V - 36 V110230 Copyright 2006 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback3 ProductFolderLinks:TPS542012348765 BOOTNCNCVSENSEPHVINGNDENATPS5420 SLVS642E APRIL2006 ASSIGNMENTSD PACKAGE(TOPVIEW) the high-sideFET F low ESRcapacitorfromBOOTpin to PH , 3 Not the V, the pin to pin to GNDpin closeto devicepackagewith a high quality,low the high side externalinductorand 2006 2013, Duty Ratio % Junction Temperature CJo1007550 IShutdown Current ASDm 25 ENA = 0 VT = 125 CJoT = 27 CJoT = -40 CJo040V INPUT Voltage Slow Start Time msSS Junction Temperature CJo1007550V = 12 VI-50-25025125T Junction Temperature CJo100755080180150170160rOn-State Resistance mDS(on)

6 W 90120130140100110-50-25025125T Junction Temperature Reference Vref Reference Vref Controllable On Time ns130140-50-25025125T Junction Temperature CJo1007550460-50-25025125T Junction Temperature CJo1007550460470530500520510fOscillator Frequency kHz 480490-50-25025125T Junction Temperature CJo1007550V = 12 Quiescent Current mAQ APRIL2006 REVISEDSEPTEMBER2013 TYPICALCHARACTERISTICSOSCILLATORFREQUENC YOPERATINGQUIESCENTCURRENTMINIMUMCONTROL LABLEON 2006 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback5 ProductFolderLinks: tps5420 VINUVLOENABLET hermalProtectionReferenceOvercurrentGate DriveOscillatorRampGeneratorVREFPHENAGND SHDNSHDNBOOTZ1Z2 SHDNSHDNSHDNSHDNVINSHDNHICCUPHICCUPSHDNS HDNNCFeed ForwardBOOTNCVINVOUT5 V BandgapSlow StartBootRegulatorErrorAmplifierGain = VREFVSENSEOVPTPS5420 SLVS642E APRIL2006 PWMswitchingfrequencyat 500 kHzswitchingfrequencyallowslessoutputind uctancefor the sameoutputripplerequirementresultingin a voltagereferencesystemproducesa precisionreferencesignalby scalingthe outputof a bandgapand scalingcircuitsare trimmedduringproductiontestingto an at (ENA)

7 And InternalSlowStartThe ENApin provideselectricalon/offcontrolof the ENApin voltageexceedsthe thresholdvoltage,the regulatorstartsoperationand the internalslowstartbeginsto the ENApin voltageis pulledbelowthe thresholdvoltage,the regulatorstopsswitchingand the pinto groundor to any V disablesthe regulatorand activatethe the TPS5420in shutdownmodeis typically18 ENApin has an internalpullupcurrentsource,allowingthe userto floatthe ENApin. If an applicationrequirescontrollingthe ENApin, use opendrainor opencollectoroutputlogicto interfacewith the pin. To limitthe start-upinrushcurrent,an internalslowstartcircuitis usedto rampup the referencevoltagefrom0 V to itsfinal internalslowstarttime is 8 ms 2006 2013,TexasInstrumentsIncorporatedProduct FolderLinks.

8 tps5420 Feed Forward Gain = APRIL2006 REVISEDSEPTEMBER2013 UndervoltageLockout(UVLO)The TPS5420incorporatesan undervoltagelockoutcircuitto keepthe devicedisabledwhenVIN (the inputvoltage)is belowthe , internalcircuitsare heldinactiveand theinternalslowstartis groundeduntilVIN exceedsthe UVLO startthresholdvoltageis reached,the internalslowstartis releasedand deviceoperatesuntil VIN falls belowthe UVLO stop typicalhysteresisin the UVLO comparatoris 330 (BOOT)Connecta F low-ESRceramiccapacitorbetweenthe BOOTpin and PH pin. Thiscapacitorprovidesthegatedrivevoltage for the X5 Rgradedielectricsare recommendeddue to (VSENSE)The outputvoltageof the regulatoris set by feedingbackthe centerpointvoltageof an externalresistordividernetworkto the VSENSEpin.

9 In steady-stateoperation,the VSENSEpin voltageshouldbe equalto the simplifythe TPS5420usesvoltagemodecontrol,a type3 compensationnetworkhas beendesignedon chipto providea highcrossoverfrequencyand a high phasemarginfor theInternalCompensationNetworkin the applicationssectionfor internalvoltagefeedforwardprovidesa constantDC powerstagegaindespiteany variationswith the stabilityanalysisand improvesthe peakrampvoltageinverselywith the inputvoltageso that the modulatorand powerstagegainareconstantat the feedforwardgain, (1)The typicalfeedforwardgain of TPS5420is (PWM)ControlTheregulatoremploysa fixedfrequencypulse-width-modulator(PWM) ,the feedbackvoltage(VSENSEpin voltage)is comparedto the constantvoltagereferenceby the high gain erroramplifierandcompensationnetworkto producea ,the errorvoltageis comparedto the rampvoltageby this way,the errorvoltagemagnitudeis convertedto a pulsewidthwhichis the duty ,the PWMoutputis fed into the gatedrivecircuitto controlthe on-timeof the implementedby sensingthe drain-to-sourcevoltageacrossthe sourcevoltageis thencomparedto a voltagelevelrepresentingthe thedrain-to-sourcevoltageexceedsthe overcurrentthresholdlimit,the overcurrentindicatoris set systemwill ignorethe overcurrentindicatorfor the leadingedgeblankingtime at the beginningof eachcycleto set true.

10 Overcurrentlimitingis high-sideMOSFETis turnedoff forthe rest of the cycleaftera overcurrentlimitingschemeis short-circuit,the overcurrentrunawaymaystill secondmodeof currentlimitingis used, ,the voltagereferenceis groundedand the high-sideMOSFETis turnedoff for the hiccuptime durationis complete,the regulatorrestartsundercontrolof the 2006 2013,TexasInstrumentsIncorporatedSubmitD ocumentationFeedback7 ProductFolderLinks: tps5420 tps5420 SLVS642E APRIL2006 TPS5420has an overvoltageprotection(OVP)circuitto minimizevoltageovershootwhenrecoveringfr omoutputfault OVPcircuitincludesan overvoltagecomparatorto comparethe VSENSEpin voltageand a thresholdof VSENSEpin voltageis higherthanthe threshold,the high-sideMOSFET will be forcedoff.