LM25005 42V, 2.5A Step-Down Switching Regulator (Rev. C)
Document overview
- Manufacturer or author: Texas Instruments, Incorporated [SNVS411,C]
- PDF pages: 28
Technical content
www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 LM2500542V,2.5AStep-DownSwitchingRegulator Check forSamples: LM25005 1FEATURES DESCRIPTION The LM25005 switchingregulatorfeaturesallof the 2• Integrated42V,160m Ω N-Channel MOSFET functionsnecessaryto implement an efficient,high• Ultra-WideInputVoltageRange from 7V to42V voltagebuck regulatorusinga minimum of external
- InternalBias Regulator components.This easy to use regulatorincludesa 42V, 160m Ω, N-channel MOSFET, with an output• AdjustableOutput Voltagefrom 1.225V currentcapabilityof 2.5 Amps. The regulatorcontrol• 1.5% Feedback ReferenceAccuracy method isbased upon currentmode controlutilizing
- CurrentMode ControlwithEmulated Inductor an emulated currentramp. Current mode control CurrentRamp providesinherentlinevoltagefeed-forward,cycle-by- cyclecurrentlimitingand ease ofloopcompensation.• SingleResistorOscillatorFrequency Setting The use of an emulatedcontrolramp reducesnoise• OscillatorSynchronizationInput sensitivityof the pulse-widthmodulation circuit,
- Programmable Soft-Start allowingreliablecontrolof very small duty cycles necessary in high inputvoltageapplications.The• Shutdown /Standby Input operatingfrequencyisprogrammable from 50kHz to• Wide Bandwidth ErrorAmplifier 500kHz. An oscillatorsynchronizationpin allows
- Thermal Shutdown multipleLM25005 regulatorstoself-synchronizeorto be synchronizedto an externalclock.Additional protectionfeaturesinclude:currentlimit,thermal shutdown and remote shutdown capability.The deviceis availablein a power enhanced HTSSOP package featuringan exposed dieattachpad to aid thermaldissipation. Package
- HTSSOP (ExposedPad) SimplifiedApplicationSchematic Pleasebe aware thatan importantnoticeconcerningavailability,standardwarranty,and use incriticalapplicationsof Texas Instrumentssemiconductorproductsand disclaimerstheretoappearsattheend ofthisdatasheet. 2Alltrademarksarethepropertyoftheirrespectiveowners. PRODUCTION DATA informationiscurrentas ofpublicationdate. Copyright© 2006–2013,Texas InstrumentsIncorporatedProductsconform to specificationsper the terms of the Texas Instrumentsstandardwarranty.Productionprocessingdoes not necessarilyincludetestingofallparameters.
SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com Connection Diagram Figure1. Top View 20-Lead HTSSOP PIN DESCRIPTIONS Pin(S) Name Description ApplicationInformation Vcc tracksVinup to9V.Beyond 9V,Vcc isregulatedto7 Volts. A 0.1uFto1uF ceramicdecouplingcapacitorisrequired.An1 VCC Outputofthebiasregulator externalvoltage(7.5V– 14V) can be appliedtothispinto reduceinternalpower dissipation. IftheSD pinvoltageisbelow0.7Vtheregulatorwillbe ina low power state.IftheSD pinvoltageisbetween 0.7Vand 1.225V theregulatorwillbe instandbymode. IftheSD pinvoltageis 2 SD Shutdown orUVLO input above 1.225Vtheregulatorwillbe operational.An external voltagedividercan be used toseta lineundervoltageshutdown threshold.IftheSD pinisleftopen circuit,a 5µA pull-upcurrent sourceconfigurestheregulatorfullyoperational. 3,4 Vin Inputsupplyvoltage Nominaloperatingrange:7V to42V The internaloscillatorcan be synchronizedtoan externalclock 5 SYNC Oscillatorsynchronizationinputoroutput withan externalpull-downdevice.MultipleLM25005 devices can be synchronizedtogetherby connectionoftheirSYNC pins. The loopcompensationnetworkshouldbe connectedbetween6 COMP Outputoftheinternalerroramplifier thispinand theFB pin. Thispinisconnectedtotheinvertinginputoftheinternalerror7 FB Feedback signalfromtheregulatedoutput amplifier.The regulationthresholdis1.225V. The internaloscillatorissetwitha singleresistor,connected 8 RT Internaloscillatorfrequencysetinput between thispinand theAGND pin.The recommended frequencyrangeis50KHz to500KHz. An externalcapacitorconnectedbetween thispinand theAGND 9 RAMP Ramp controlsignal pinsetstheramp slopeused forcurrentmode control. Recommended capacitorrange50pF to2000pF.
10 AGND Analogground Internalreferencefortheregulatorcontrolfunctions
An externalcapacitorand an internal10µA currentsourceset thetimeconstantfortheriseoftheerroramp reference.The SS11 SS Soft-start pinisheldlowduringstandby,Vcc UVLO and thermal shutdown. 12 OUT Outputvoltageconnection Connectdirectlytotheregulatedoutputvoltage. 13,14 PGND Power ground Low sidereferenceforthePRE switchand theISsense resistor.
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www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 PIN DESCRIPTIONS (continued) Pin(S) Name Description ApplicationInformation Currentmeasurement connectionforthere-circulatingdiode.An internalsense resistorand a sample/holdcircuitsense thediode 15,16 IS Currentsense currentneartheconclusionoftheoff-time.Thiscurrent measurement providestheDC leveloftheemulatedcurrent ramp. The sourceterminaloftheinternalbuck switch.The SW pin 17,18 SW Switchingnode shouldbe connectedtotheexternalSchottkydiodeand tothe buck inductor. Thisopen drainoutputcan be connectedtoSW pintoaid chargingthebootstrapcapacitorduringverylightloadconditions Pre-chargeassistforthebootstrap orinapplicationswhere theoutputmay be pre-chargedbefore19 PRE capacitor theLM25005 isenabled.An internalpre-chargeMOSFET is turnedon for250ns each cyclejustpriortotheon-timeinterval ofthebuck switch. An externalcapacitorisrequiredbetween theBST and theSW pins.A 0.022µF ceramiccapacitorisrecommended. The20 BST Boostinputforbootstrapcapacitor capacitorischargedfromVcc viaan internaldiodeduringthe off-timeofthebuck switch. Exposed metalpad on theundersideofthedevice.Itis NA EP Exposed Pad recommended toconnectthispad tothePWB groundplane,in ordertoaidinheatdissipation. These deviceshave limitedbuilt-inESD protection.The leadsshouldbe shortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamage totheMOS gates. AbsoluteMaximum Ratings(1)(2) VIN toGND 45V BST toGND 60V PRE toGND 45V SW toGND (SteadyState) -1.5V BST toVCC 45V VCC toGND 14V BST toSW 14V OUT toGND LimitedtoVin SD, SYNC, SS, FB toGND 7V ESD Rating(3) Human Body Model 2kV StorageTemperatureRange -65°C to+150°C (1) AbsoluteMaximum Ratingsarelimitsbeyond whichdamage tothedevicemay occur.OperatingRatingsareconditionsunderwhich operationofthedeviceisintendedtobe functional.Forensuredspecificationsand testconditions,see theElectricalCharacteristics. (2) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTexas InstrumentsSalesOffice/Distributorsforavailabilityand specifications. (3) The human body model isa 100pF capacitordischargedthrougha 1.5kΩ resistorintoeach pin. OperatingRatings(1) VIN 7V to42V OperationJunctionTemperature −40°C to+ 125°C (1) AbsoluteMaximum Ratingsarelimitsbeyond whichdamage tothedevicemay occur.OperatingRatingsareconditionsunderwhich operationofthedeviceisintendedtobe functional.Forensuredspecificationsand testconditions,see theElectricalCharacteristics. Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LM25005
SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com ElectricalCharacteristics SpecificationswithstandardtypefaceareforTJ = 25°C, and thosewithboldfacetypeapplyoverfullOperatingJunction Temperature range.VIN = 24V,R T = 32.4kΩ unlessotherwisestated.(1) Symbol Parameter Conditions Min Typ Max Units STARTUP REGULATOR VccReg Vcc RegulatorOutput 6.85 7.15 7.45 V Vcc LDO Mode turn-off 9 V Vcc CurrentLimit Vcc = 0V 20 mA VCC SUPPLY Vcc UVLO Threshold (Vccincreasing) 5.95 6.35 6.75 V Vcc UndervoltageHysteresis 1 V BiasCurrent(Iin) FB = 1.3V 3 4.5 mA Shutdown Current(Iin) SD = 0V 50 85 µA SHUTDOWN THRESHOLDS Shutdown Threshold (SD Increasing) 0.5 0.7 0.9 V Shutdown Hysteresis 0.1 V StandbyThreshold (StandbyIncreasing) 1.18 1.225 1.27 V StandbyHysteresis 0.1 V SD Pull-upCurrentSource 5 µA SWITCH CHARACTERSICS Buck SwitchRds(on) 160 320 m Ω BOOST UVLO 3.8 V BOOST UVLO Hysteresis 0.56 V Pre-chargeSwitchRds(on) 75 Ω Pre-chargeSwitchon-time 275 ns CURRENT LIMIT Cycleby CycleCurrentLimit RAMP = 0V 3 3.5 4.25 A Cycleby CycleCurrentLimitDelay RAMP = 2.5V 100 ns SOFT-START SS CurrentSource 7 10 14 µA OSCILLATOR Frequency1 180 200 220 KHz Frequency2 RT = 11kΩ 425 485 525 KHz SYNC SourceImpedance 10 kΩ SYNC SinkImpedance 160 Ω SYNC Threshold(falling) 1.4 V Upper SYNC Frequency 550 KHz SYNC PulseWidthMinimum 15 ns RAMP GENERATOR Ramp Current1 Vin= 36V,Vout=10V 136 160 184 µA Ramp Current2 Vin= 10V,Vout=10V 18 25 32 µA PWM COMPARATOR ForcedOff-time 500 ns Min On-time 80 ns COMP toPWM ComparatorOffset 0.7 V (1) Min and Max limitsare100% productiontestedat25°C. Limitsovertheoperatingtemperaturerangeareensuredthroughcorrelation usingStatisticalQualityControl(SQC) methods.Limitsareused tocalculateAverageOutgoingQualityLevel(AOQL).
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www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 ElectricalCharacteristics(continued) SpecificationswithstandardtypefaceareforTJ = 25°C, and thosewithboldfacetypeapplyoverfullOperatingJunction Temperature range.VIN = 24V,R T = 32.4kΩ unlessotherwisestated.(1) Symbol Parameter Conditions Min Typ Max Units ERROR AMPLIFIER Feedback Voltage Vfb= COMP 1.207 1.225 1.243 V FB BiasCurrent 10 nA DC Gain 70 dB COMP Sink/SourceCurrent 3 mA UnityGain Bandwidth 3 MHz THERMAL SHUTDOWN Tsd ThermalShutdown Threshold 165 °C ThermalShutdown Hysteresis 25 °C THERMAL RESISTANCE θJC JunctiontoCase 4 °C/W θJA JunctiontoAmbient 40 °C/W Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LM25005
VCC (V) VIN (V) Ramp Up Ramp Down PHASE (° ) 10k 100k 1M 10M 100M FREQUENCY (Hz) -30 -20 -10 GAIN (dB) -135 -90 -45 135 180 225 GAIN PHASE TEMPERATURE ( oC) NORMALIZED SOFTSTART CURRENT -50 -25 0 25 50 75 100 125 0.90 0.95 1.00 1.05 1.10 0 4 16 20 24 ICC (mA) VCC (V) 8 12 TEMPERATURE ( oC) NORMALIZED OSCILLATOR FREQUENCY-50 -25 0 25 50 75 100 125 0.990 0.995 1.000 1.005 1.010 RT (k:) OSCILLATOR FREQUENCY (kHz) 1 10 100 1000 100 1000 LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com TypicalPerformance Characteristics OscillatorFrequency vs OscillatorFrequency vs R T Temperature FOSC = 200kHz Figure2. Figure3. SoftStartCurrentvs Temperature VCC vs ICC ,VIN = 12V Figure4. Figure5. ErrorAmplifierGain/Phase VCC vs VIN,R L = 7kΩ A VCL = 101 Figure6. Figure7.
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EFFICIENCY (%) IOUT (A) VIN = 24V VIN = 7V LM25005 www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 TypicalPerformance Characteristics(continued) Demoboard Efficiency vs IOUT and VIN Figure8. Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LM25005
S R Q Q AGND IS CLK SS PRE 3, 4 5 8 9 12 13, 14 SD Ir LM25005 SHUTDOWN STANDBY REGULATOR SYNC SYNC OSCILLATOR RAMP OUT PGND CLK CLKCOMP ERROR AMP 21k 330p C11 330p C10 150 1.65k 5.11k 33 PH 0.022 0.47 CSHD6-100C 15, 16 17, 18 THERMAL SHUTDOWNUVLO UVLO CLK DIS VCC LEVEL SHIFT DRIVER 1.225V 1.225V 0.7V 0.7V 49.9k 0.01C6 open OPEN C12 OPEN 0.01 2.2 2.2 OPEN 7V ± 42V VIN VIN 1.75V PWM C_LIMIT 10 PA 5 PA VIN TRACK SAMPLE and HOLD 0.5V/A RAMP GENERATOR Ir = (5 PA x (VIN ± VOUT )) + 25 PA LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com TypicalApplicationCircuitand Block Diagram
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6.3V LM25005 www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 DetailedOperatingDescription The LM25005 switchingregulatorfeaturesallofthefunctionsnecessarytoimplementan efficienthighvoltage buck regulatorusinga minimum ofexternalcomponents.Thiseasy touse regulatorintegratesa 42V N-Channel buck switchwithan outputcurrentcapabilityof 2.5 Amps. The regulatorcontrolmethod isbased on current mode controlutilizingan emulatedcurrentramp.Peak currentmode controlprovidesinherentlinevoltagefeed- forward,cycle-by-cyclecurrentlimiting,and ease ofloopcompensation.The use ofan emulatedcontrolramp reducesnoisesensitivityof the pulse-widthmodulationcircuit,allowingreliableprocessingof verysmallduty cyclesnecessaryinhighinputvoltageapplications.The operatingfrequencyisuserprogrammable from 50kHz to 500kHz. An oscillatorsynchronizationpin allowsmultipleLM25005 regulatorsto selfsynchronizeor be synchronizedto an externalclock.The outputvoltagecan be setas low as 1.225V.Faultprotectionfeatures include,currentlimiting,thermalshutdown and remote shutdown capability.The deviceis availablein the HTSSOP package featuringan exposed pad toaidthermaldissipation. The functionalblockdiagramand typicalapplicationoftheLM25005 areshown intheTypicalApplicationCircuit and Block Diagram. The LM25005 can be appliedin numerous applicationsto efficientlystep-downa high, unregulatedinputvoltage.The deviceiswellsuitedfortelecom,industrialand automotivepower bus voltage ranges. High VoltageStart-UpRegulator The LM25005 containsa dual-modeinternalhighvoltagestartupregulatorthatprovidestheVcc biassupplyfor the PWM controllerand boot-strapMOSFET gate driver.The inputpin(Vin)can be connecteddirectlyto the inputvoltage,as highas 42 Volts.For inputvoltagesbelow 9V, a low dropoutswitchconnectsVcc directlyto Vin.Inthissupplyrange,Vcc isapproximatelyequaltoVin.For Vin voltagegreaterthan9V, thelow dropout switchisdisabledand the Vcc regulatorisenabledto maintainVcc at approximately7V. The wide operating rangeof7V to42V isachievedthroughtheuse ofthisdualmode regulator. The outputoftheVcc regulatoriscurrentlimitedto20mA. Upon power up,theregulatorsourcescurrentintothe capacitorconnectedtotheVcc pin.When thevoltageattheVcc pinexceeds theVcc UVLO thresholdof6.3V and theSD pinisgreaterthan1.225V,theoutputswitchisenabledand a soft-startsequence begins.The output switchremainsenableduntilVcc fallsbelow5.3VortheSD pinfallsbelow1.125V. An auxiliarysupplyvoltagecan be appliedto the Vcc pinto reduce the IC power dissipation.Ifthe auxiliary voltageisgreaterthan7.3V,theinternalregulatorwillessentiallyshutoff,reducingtheIC power dissipation.The Vcc regulatorseriespass transistorincludesa diodebetween Vcc and Vinthatshouldnotbe forwardbiasedin normaloperation.ThereforetheauxiliaryVcc voltageshouldneverexceed theVinvoltage. In highvoltageapplicationsextracare shouldbe takento ensure the Vin pindoes not exceed the absolute maximum voltageratingof45V. Duringlineor loadtransients,voltageringingon theVin linethatexceeds the AbsoluteMaximum Ratingscan damage the IC.Both carefulPC board layoutand the use of qualitybypass capacitorslocatedclosetotheVinand GND pinsareessential. Figure9. Vin and Vcc Sequencing Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LM25005
R T = - 580 x 10-9 135 x 10-12 F LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com Shutdown /Standby The LM25005 containsa duallevelShutdown (SD) circuit.When theSD pinvoltageisbelow 0.7V,theregulator isina low currentshutdown mode. When the SD pinvoltageisgreaterthan 0.7V but lessthan 1.225V,the regulatorisinstandbymode. Instandbymode theVcc regulatorisactivebuttheoutputswitchisdisabled.When theSD pinvoltageexceeds 1.225V,theoutputswitchisenabledand normaloperationbegins.An internal5µA pull-upcurrentsourceconfigurestheregulatortobe fullyoperationaliftheSD pinisleftopen. An externalset-pointvoltagedividerfrom Vin to GND can be used to setthe operationalinputrange of the regulator.The dividermust be designedsuch thatthevoltageattheSD pinwillbe greaterthan1.225V when Vin isinthedesiredoperatingrange.The internal5µA pull-upcurrentsourcemust be includedincalculationsofthe externalset-pointdivider.Hysteresisof 0.1V isincludedforboth the shutdown and standbythresholds.The voltageattheSD pinshouldneverexceed 8V. When usingan externalset-pointdivider,itmay be necessaryto clamp theSD pintolimititsvoltageathighinputvoltageconditions. The SD pincan alsobe used to implementvariousremote enable/ disablefunctions.Pullingthe UVLO pin belowthe0.7Vthresholdtotallydisablesthecontroller.IftheSD pinvoltageisabove 1.225Vtheregulatorwillbe operational. Oscillatorand Sync Capability The LM25005 oscillatorfrequencyissetby a singleexternalresistorconnectedbetween the RT pinand the AGND pin.The R T resistorshouldbe locatedveryclosetothedeviceand connecteddirectlytothepinsoftheIC (RT and AGND).To set a desiredoscillatorfrequency(F),the necessaryvalue forthe R T resistorcan be calculatedfromthefollowingequation: (1) The SYNC pincan be used tosynchronizetheinternaloscillatortoan externalclock.The externalclockmust be ofhigherfrequency thanthefree-runningfrequencysetby theR T resistor.A clockcircuitwithan open drain outputistherecommended interfacefrom theexternalclocktotheSYNC pin.The clockpulsedurationshould be greaterthan15 ns. Figure10.Sync from ExternalClock Figure11.Sync from MultipleDevices MultipleLM25005 and/orLM5005 devicescan be synchronizedtogethersimplyby connectingthe SYNC pins together.In thisconfigurationallof the deviceswillbe synchronizedto the highestfrequencydevice.The diagram inFigure12 illustratesthe SYNC input/outputfeaturesof the LM25005. The internaloscillatorcircuit drivestheSYNC pinwitha strongpull-down/weak pull-upinverter.When theSYNC pinispulledlow eitherby theinternaloscillatororan externalclock,theramp cycleoftheoscillatoristerminatedand a new oscillatorcycle begins.Thus,iftheSYNC pinsofseveralLM25005 IC’s areconnectedtogether,theIC withthehighestinternal clockfrequencywillpulltheconnectedSYNC pinslow firstand terminatetheoscillatorramp cyclesoftheother IC’s.The LM25005 orLM5005 withthehighestprogrammed clockfrequencywillserveas themasterand control theswitchingfrequencyoftheallthedeviceswithloweroscillatorfrequency.
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S R Q Q DEADTIME ONE-SHOT 2.5V I = f(RT) LM25005 www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 Figure12. SimplifiedOscillatorBlock Diagram and SYNC I/OCircuit ErrorAmplifierand PWM Comparator The internalhigh gain erroramplifiergeneratesan errorsignalproportionalto the differencebetween the regulatedoutputvoltageand an internalprecisionreference(1.225V).The outputof the erroramplifieris connectedto the COMP pinallowingthe user to provideloopcompensationcomponents,generallya typeII network,as illustratedinTypicalApplicationCircuitand BlockDiagram. Thisnetworkcreatesa poleat DC, a zero and a noisereducinghighfrequencypole.The PWM comparatorcompares the emulatedcurrentsense signalfromtheRAMP generatortotheerroramplifieroutputvoltageattheCOMP pin. RAMP Generator The ramp signalused inthepulsewidthmodulatorforcurrentmode controlistypicallyderiveddirectlyfromthe buck switchcurrent.Thisswitchcurrentcorrespondstothepositiveslopeportionoftheoutputinductorcurrent. Using thissignalforthePWM ramp simplifiesthecontrollooptransferfunctiontoa singlepoleresponseand providesinherentinputvoltagefeed-forwardcompensation.The disadvantageofusingthebuck switchcurrent signalforPWM controlisthelargeleadingedge spikedue tocircuitparasiticsthatmust be filteredor blanked. Also,the currentmeasurement may introducesignificantpropagationdelays.The filtering,blankingtimeand propagationdelaylimitthe minimum achievablepulsewidth.In applicationswhere the inputvoltagemay be relativelylargeincomparisontotheoutputvoltage,controllingsmallpulsewidthsand dutycyclesisnecessaryfor regulation.The LM25005 utilizesa uniqueramp generator,which does not actuallymeasure the buck switch currentbut ratherreconstructsthe signal.Reconstructingor emulatingthe inductorcurrentprovidesa ramp signalto the PWM comparatorthatisfreeof leadingedge spikesand measurement or filteringdelays.The currentreconstructioniscomprisedoftwo elements;a sample & holdDC leveland an emulatedcurrentramp. Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LM25005
0.5V/A RAMP TON tON C RAMP (5P x (VIN ± VOUT ) + 25P) x LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com Figure13. Composition ofCurrentSense Signal The Sample and Hold DC levelillustratedin Figure13. isderivedfrom a measurement of the re-circulating Schottkydiodeanode current.The re-circulatingdiodeanode shouldbe connectedto the IS pin.The diode currentflowsthroughan internalcurrentsense resistorbetween theIS and PGND pins.The voltagelevelacross thesense resistorissampled and heldjustpriortotheonsetofthenextconductionintervalofthebuck switch. The diode currentsensingand sample & hold providethe dc levelof the reconstructedcurrentsignal.The positiveslopeinductorcurrentramp isemulatedby an externalcapacitorconnectedfromtheRAMP pintoAGND and an internalvoltagecontrolledcurrentsource.The ramp currentsourcethatemulatestheinductorcurrentisa functionoftheVinand Voutvoltagesperthefollowingequation: IRAMP = (5µ x (Vin– Vout))+ 25µA (2) ProperselectionoftheRAMP capacitordepends upon theselectedvalueoftheoutputinductor.The valueof C RAMP can be selectedfrom:C RAMP = L x 10-5,where L isthevalueoftheoutputinductorinHenrys.With this value,thescalefactoroftheemulatedcurrentramp willbe approximatelyequaltothescalefactorofthedc level sample and hold( 0.5V /A).The C RAMP capacitorshouldbe locatedveryclosetothedeviceand connected directlytothepinsoftheIC (RAMP and AGND). For dutycyclesgreaterthan 50%, peak currentmode controlcircuitsare subjectto sub-harmonicoscillation. Sub-harmonicoscillationisnormallycharacterizedby observingalternatingwide and narrowpulsesattheswitch node. Adding a fixedslope voltageramp (slopecompensation)to the currentsense signalpreventsthis oscillation.The 25µA ofoffsetcurrentprovidedfrom theemulatedcurrentsourceadds some fixedslopetothe ramp signal.Insome highoutputvoltage,highdutycycleapplications,additionalslopemay be required.Inthese applications,a pull-upresistormay be added between the VCC and RAMP pinsto increasethe ramp slope compensation. ForVOUT > 7.5V: Calculateoptimalslopecurrent,IOS = VOUT x 5µA/V. Forexample,atVOUT = 10V,IOS = 50µA. Installa resistorfromtheRAMP pintoVCC : R RAMP = VCC /(IOS -25µA)
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www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 Figure14. R RAMP toVCC forVOUT > 7.5V CurrentLimit The LM25005 containsa uniquecurrentmonitoringscheme forcontroland over-currentprotection.When set correctly,theemulatedcurrentsense signalprovidesa signalwhich isproportionaltothebuck switchcurrent witha scalefactorof 0.5 V / A. The emulatedramp signalisappliedto the currentlimitcomparator.Ifthe emulated ramp signalexceeds 1.75V (3.5A)the presentcurrentcycleis terminated(cycle-by-cyclecurrent limiting).In applicationswithsmalloutputinductanceand highinputvoltagethe switchcurrentmay overshoot due to the propagationdelayof the currentlimitcomparator.Ifan overshootshouldoccur,the diodecurrent samplingcircuitwilldetecttheexcessinductorcurrentduringtheoff-timeofthebuck switch.IftheSample and Hold DC Levelexceeds the1.75V currentlimitthreshold,thebuck switchwillbe disabledand skippulsesuntil thediodecurrentsamplingcircuitdetectstheinductorcurrenthas decayed below thecurrentlimitthreshold.This approachpreventscurrentrunaway conditionsdue topropagationdelaysorinductorsaturationsincetheinductor currentisforcedtodecay followingany currentovershoot. Soft-Start The soft-startfeatureallowstheregulatortograduallyreachtheinitialsteadystateoperatingpoint,thusreducing start-upstressesand surges.The internalsoft-startcurrentsource,setto10µA, graduallyincreasesthevoltage ofan externalsoft-startcapacitorconnectedtotheSS pin.The soft-startcapacitorvoltageisconnectedtothe referenceinputof the erroramplifier.Varioussequencingand trackingschemes can be implementedusing externalcircuitsthatlimitorclamp thevoltageleveloftheSS pin. In the eventa faultisdetected(over-temperature,Vcc UVLO, SD) the soft-startcapacitorwillbe discharged. When thefaultconditionisno longerpresenta new soft-startsequence willcommence. Boost Pin The LM25005 integratesan N-Channelbuck switchand associatedfloatinghighvoltagelevelshift/gatedriver. Thisgatedrivercircuitworksinconjunctionwithan internaldiodeand an externalbootstrapcapacitor.A 0.022µF ceramiccapacitor,connectedwithshorttracesbetween theBST pinand SW pin,isrecommended. Duringthe off-timeofthebuck switch,theSW pinvoltageisapproximately- 0.5V and thebootstrapcapacitorischarged fromVcc throughtheinternalbootstrapdiode.When operatingwitha highPWM dutycycle,thebuck switchwill be forcedoffeach cyclefor500ns toensurethatthebootstrapcapacitorisrecharged. Under verylightloadconditionsor when theoutputvoltageispre-charged,theSW voltagewillnotremainlow duringtheoff-timeofthebuck switch.Iftheinductorcurrentfallstozeroand theSW pinrises,thebootstrap capacitorwillnot receivesufficientvoltageto operatethe buck switchgate driver.For theseapplications,the PRE pin can be connected to the SW pin to pre-chargethe bootstrapcapacitor.The internalpre-charge MOSFET and diodeconnectedbetween thePRE pinand PGND turnson each cyclefor250ns justpriortothe onsetofa new switchingcycle.IftheSW pinisata normalnegativevoltagelevel(continuousconductionmode), thenno currentwillflowthroughthepre-chargeMOSFET/diode. Thermal Protection InternalThermalShutdown circuitryisprovidedtoprotecttheintegratedcircuitintheeventthemaximum junction temperatureisexceeded.When activated,typicallyat 165 degrees Celsius,the controllerisforcedintoa low power resetstate,disablingthe outputdriverand the bias regulator.This featureis providedto prevent catastrophicfailuresfromaccidentaldeviceoverheating. Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LM25005
L1 = 5V x (42V ± 5V) 0.5A x 300 kHz x 42V = 29 PH L1 = VOUT x (VIN(max) ± VOUT ) IRIPPLE x FS x VIN(max) IPK+ L1 Current 0 mA IPK- IOIRIPPLE 1/Fs R T = [(1 / 300 x 103) ± 580 x 10-9] 135 x 10-12 LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com
APPLICATION INFORMATION
The procedureforcalculatingtheexternalcomponents isillustratedwiththefollowingdesignexample.The Billof Materialsforthisdesign is listedin 5V, 2.5A Demo Board Billof Materials. The circuitshown in Typical ApplicationCircuitand BlockDiagram isconfiguredforthefollowingspecifications:
- VOUT = 5V
- VIN = 7V to42V
- Fs = 300 KHz
- Minimum loadcurrent(forCCM) = 250 mA
- Maximum loadcurrent= 2.5A R3 (RT) R T setstheoscillatorswitchingfrequency.Generally,higherfrequencyapplicationsare smallerbuthave higher losses.Operationat300KHz was selectedforthisexample as a reasonablecompromise forbothsmallsizeand highefficiency.The valueofR T for300KHz switchingfrequencycan be calculatedas follows: (3) The neareststandardvalueof21 kΩ was chosen forRT. The inductorvalue is determinedbased on the operatingfrequency,load current,ripplecurrent,and the minimum and maximum inputvoltage(VIN(min),VIN(max)). Figure15. InductorCurrentWaveform To keep the circuitincontinuousconductionmode (CCM), the maximum ripplecurrentIRIPPLE shouldbe less thantwicetheminimum loadcurrent,or0.5Ap-p.Usingthisvalueofripplecurrent,thevalueofinductor(L1)is calculatedusingthefollowing: (4) (5) Thisprocedureprovidesa guidetoselectthevalueofL1.The neareststandardvalue(33µH) willbe used.L1 must be ratedforthepeak current(IPK+ )topreventsaturation.Duringnormalloadingconditions,thepeak current occursatmaximum loadcurrentplusmaximum ripple.Duringan overloadconditionthepeak currentislimitedto 3.5A nominal(4.25Amaximum). The selectedinductor(see 5V, 2.5A Demo Board Billof Materials) has a conservative6.2 Amp saturationcurrentrating.For thismanufacturer,the saturationratingisdefinedas the currentnecessaryfortheinductancetoreduceby 30%, at20°C.
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'VOUT = 'IL x 1 8 x FS x COUT ESR + § LM25005 www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 C3 (CRAMP ) Withtheinductorvalueselected,thevalueofC3 (CRAMP )necessaryfortheemulationramp circuitis: C RAMP = L x 10-5 where
- L isinHenrys(WithL1 selectedfor33µH therecommended valueforC3 is330pF) (6) C9, C10 The outputcapacitorsC9, and C10, smooth the inductorripplecurrentand providea source of charge for transientloadingconditions.For thisdesigna 22µF ceramiccapacitorand a 150µF SP organiccapacitorwere selected.The ceramiccapacitorprovidesultralow ESR to reduce the outputripplevoltageand noisespikes, whiletheSP capacitorprovidesa largebulkcapacitanceina smallvolume fortransientloadingconditions.An approximationfortheoutputripplevoltageis: (7) A Schottkytype re-circulatingdiode is requiredfor allLM25005 applications.Ultra-fastdiodes are not recommended and may resultindamage to the IC due to reverserecoverycurrenttransients.The near ideal reverserecoverycharacteristicsand low forwardvoltagedropareparticularlyimportantdiodecharacteristicsfor high inputvoltageand low outputvoltageapplicationscommon to the LM25005. The reverserecovery characteristicdetermineshow longthecurrentsurgelastseach cyclewhen thebuck switchisturnedon.The reverserecoverycharacteristicsofSchottkydiodesminimizethepeak instantaneouspower inthebuck switch occurringduringturn-oneach cycle.The resultingswitchinglossesofthebuck switchare significantlyreduced when usinga Schottkydiode.The reversebreakdown ratingshouldbe selectedforthemaximum VIN,plussome safetymargin. The forwardvoltagedrophas a significantimpacton theconversionefficiency,especiallyforapplicationswitha low outputvoltage.“Rated” currentfordiodesvary widelyfrom variousmanufactures.The worstcase isto assume a shortcircuitloadcondition.Inthiscase thediodewillcarrytheoutputcurrentalmostcontinuously.For the LM25005 thiscurrentcan be as high as 3.5A.Assuming a worstcase 1V drop acrossthe diode,the maximum diodepower dissipationcan be as highas 3.5W. For thereferencedesigna 60V Schottkyina DPAK package was selected. C1, C2 The regulatorsupplyvoltagehas a largesource impedance at the switchingfrequency.Good qualityinput capacitorsare necessaryto limitthe ripplevoltageat the VIN pinwhilesupplyingmost of the switchcurrent duringtheon-time.When thebuck switchturnson,thecurrentintotheVIN pinstepstothelowerpeak ofthe inductorcurrentwaveform,ramps up tothepeak value,thendropstozeroatturn-off.The averagecurrentinto VIN duringtheon-timeistheloadcurrent.The inputcapacitanceshouldbe selectedforRMS currentratingand minimum ripplevoltage.A good approximationfortherequiredripplecurrentratingnecessaryisIRMS > IOUT /2. Qualityceramic capacitorswitha low ESR should be selectedforthe inputfilter.To allowforcapacitor tolerancesand voltageeffects,two 2.2µF,100V ceramiccapacitorswillbe used.Ifstepinputvoltagetransients areexpectednearthemaximum ratingoftheLM25005, a carefulevaluationofringingand possiblespikesatthe deviceVIN pinshouldbe completed.An additionaldamping networkor inputvoltageclamp may be requiredin thesecases. The capacitorattheVCC pinprovidesnoisefilteringand stabilityfortheVCC regulator.The recommended value ofC8 shouldbe no smallerthan0.1µF, and shouldbe a good quality,low ESR, ceramiccapacitor.A valueof 0.47µF was selectedforthisdesign. Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LM25005
R2 = 1.225 x R1 VIN(min) + (5 x 10-6 x R1) ± 1.225 §¨© tss = C4 x 1.225V 10 PA LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com The bootstrapcapacitorbetween theBST and theSW pinssuppliesthegatecurrenttochargethebuck switch gateatturn-on.The recommended valueofC7 is0.022µF, and shouldbe a good quality,low ESR, ceramic capacitor. The capacitorattheSS pindeterminesthesoft-starttime,i.e.thetimeforthereferencevoltageand theoutput voltage,toreachthefinalregulatedvalue.The timeisdeterminedfrom: (8) Forthisapplication,a C4 valueof0.01µF was chosen whichcorrespondstoa soft-starttimeof1 ms. R5, R6 R5 and R6 settheoutputvoltagelevel,theratiooftheseresistorsiscalculatedfrom: R5/R6 = (VOUT /1.225V)-1 (9) For a 5V output,the R5/R6 ratiocalculatesto 3.082.The resistorsshouldbe chosen from standardvalue resistors,a good startingpointisselectionintherangeof1.0kΩ -10 kΩ.Valuesof5.11kΩ forR5, and 1.65kΩ forR6 were selected. R1, R2, C12 A voltagedividercan be connectedtotheSD pintoseta minimum operatingvoltageVin(min)fortheregulator.If thisfeatureisrequired,the easiestapproach to selectthe dividerresistorvaluesisto selecta valueforR1 (between10 kΩ and 100 kΩ recommended) thencalculateR2 from: (10) CapacitorC12 providesfilteringforthedivider.The voltageattheSD pinshouldneverexceed 8V, when using an externalset-pointdivideritmay be necessaryto clamp the SD pin at high inputvoltageconditions.The referencedesignutilizesthefullrangeoftheLM25005 (7V to42V);thereforethesecomponents can be omitted. WiththeSD pinopen circuittheLM25005 respondsonce theVcc UVLO thresholdissatisfied. R7, C11 A snubbernetworkacrossthepower diodereducesringingand spikesattheswitchingnode.Excessiveringing and spikescan cause erraticoperationand couplespikesand noisetotheoutput.Inthelimit,spikesbeyond the ratingoftheLM25005 orthere-circulatingdiodecan damage thesedevices.Selectingthevaluesforthesnubber isbestaccomplishedthroughempiricalmethods.First,make suretheleadlengthsforthesnubberconnections are very short.For the currentlevelstypicalforthe LM25005 a resistorvaluebetween 5 and 20 Ohms is adequate.Increasingthe valueof the snubber capacitorresultsinmore damping but higherlosses.Selecta minimum valueofC11 thatprovidesadequatedamping oftheSW pinwaveform athighload.
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0.000 dB 0.0 deg 100 1k START 50.000 Hz 10k STOP 50 000.000 Hz /DIV 10.000 dB 45.000 deg GAIN PHASE LM25005 www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 R4, C5, C6 These components configuretheerroramplifiergaincharacteristicstoaccomplisha stableoverallloopgain.One advantageofcurrentmode controlistheabilitytoclosetheloopwithonlytwo feedbackcomponents,R4 and C5. The overallloopgainistheproductofthemodulatorgainand theerroramplifiergain.The DC modulatorgainof theLM25005 isas follows: DC Gain(MOD) = G m(MOD) x R LOAD = 2 x R LOAD (11) The dominantlow frequencypoleof the modulatorisdeterminedby the loadresistance(RLOAD ,)and output capacitance(COUT ).The cornerfrequencyofthispoleis: fp(MOD) = 1 /(2π R LOAD C OUT ) (12) ForR LOAD = 5 Ω and C OUT = 177 µF thenfp(MOD) = 180Hz DC Gain(MOD) = 2 x 5 = 10 = 20 dB For the design example of TypicalApplicationCircuitand Block Diagram the followingmodulatorgain vs. frequencycharacteristicwas measured as shown inFigure16. Figure16. Gain and Phase ofModulator R LOAD = 5 Ohms and C OUT = 177 µF Components R4 and C5 configuretheerroramplifieras a typeIIconfigurationwhich has a poleatDC and a zeroatfZ = 1 /(2πR4C5). The erroramplifierzerocancelsthemodulatorpoleleavinga singlepoleresponseat thecrossoverfrequencyoftheloopgain.A singlepoleresponseatthecrossoverfrequencyyieldsa verystable loopwith90 degreesofphase margin. For the design example, a targetloop bandwidth (crossoverfrequency)of 20 kHz was selected.The compensationnetworkzero(fZ)shouldbe selectedatleastan orderofmagnitudelessthanthetargetcrossover frequency.ThisconstrainstheproductofR4 and C5 fora desiredcompensationnetworkzero1 /(2π R4 C5) to be lessthan2kHz.IncreasingR4 whileproportionallydecreasingC5, increasestheerroramp gain.Conversely, decreasingR4 whileproportionallyincreasingC5, decreasestheerroramp gain.Forthedesignexample C5 was selectedfor0.01µF and R4 was selectedfor49.9kΩ.These valuesconfigurethecompensationnetworkzeroat 320 Hz.The erroramp gainatfrequenciesgreaterthanfZ is:R4 /R5, whichisapproximately10 (20dB). Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LM25005
0.000 dB 0.0 deg 100 1k START 50.000 Hz 10k STOP 50 000.000 Hz /DIV 10.000 dB 45.000 deg GAIN PHASE REF LEVEL 0.000 dB 0.0 deg 100 1k START 50.000 Hz 10k STOP 50 000.000 Hz /DIV 10.000 dB 45.000 deg0 GAIN PHASE LM25005 SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com Figure17. ErrorAmplifierGain and Phase The overallloopcan be predictedas thesum (indB) ofthemodulatorgainand theerroramp gain. Figure18. OverallLoop Gain and Phase Ifa networkanalyzerisavailable,the modulatorgaincan be measured and the erroramplifiergaincan be configuredforthe desiredloop transferfunction.Ifa network analyzeris not available,the erroramplifier compensation components can be designed with the guidelinesgiven.Step load transienttestscan be performedtoverifyacceptableperformance.The steploadgoalisminimum overshootwitha damped response. C6 can be added tothecompensationnetworktodecreasenoisesusceptibilityoftheerroramplifier.The value of C6 must be sufficientlysmallsincethe additionof thiscapacitoradds a poleinthe erroramplifiertransfer function.Thispolemust be wellbeyond theloopcrossoverfrequency.A good approximationofthelocationof thepoleadded by C6 is:fp2 = fzx C5 /C6.
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www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 BIAS POWER DISSIPATION REDUCTION Buck regulatorsoperatingwithhighinputvoltagecan dissipatean appreciableamount ofpower forthebiasof theIC.The VCC regulatormust step-downtheinputvoltageVIN toa nominalVCC levelof7V. The largevoltage dropacrosstheVCC regulatortranslatesintoa largepower dissipationwithintheVcc regulator.Thereareseveral techniquesthatcan significantlyreducethisbiasregulatorpower dissipation.Figure19 and Figure20 depicttwo methods tobiastheIC fromtheoutputvoltage.Ineach case theinternalVcc regulatorisused toinitiallybiasthe VCC pin.Aftertheoutputvoltageisestablished,theVCC pinpotentialisraisedabove thenominal7V regulation level,which effectivelydisablesthe internalVCC regulator.The voltageappliedto the VCC pinshouldnever exceed 14V.The VCC voltageshouldneverbe largerthantheVIN voltage. Figure19. VCC Bias from VOUT for8V < VOUT < 14V Figure20. VCC Bias withAdditionalWinding on theOutput Inductor Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:LM25005
SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com PCB LAYOUT AND THERMAL CONSIDERATIONS The circuitintheTypicalApplicationCircuitand BlockDiagram servesas botha blockdiagramoftheLM25005 and a typicalapplicationboard schematicforthe LM25005. In a buck regulatorthereare two loopswhere currentsare switchedveryfast.The firstloopstartsfrom theinputcapacitors,totheregulatorVIN pin,tothe regulatorSW pin,totheinductorthenouttotheload.The second loopstartsfromtheoutputcapacitorground, totheregulatorPGND pins,totheregulatorIS pins,tothediodeanode,totheinductorand thenouttotheload. Minimizingthe looparea of thesetwo loopsreducesthe strayinductanceand minimizesnoiseand possible erraticoperation.A ground plane in the PC board isrecommended as a means to connectthe inputfilter capacitorstotheoutputfiltercapacitorsand thePGND pinsoftheregulator.Connectallofthelowpower ground connections(CSS ,R T,C RAMP ) directlytotheregulatorAGND pin.Connect theAGND and PGND pinstogether throughthetopsidecopperareacoveringtheentireundersideofthedevice.Placeseveralviasinthisunderside copperareatothegroundplane. The two highestpower dissipatingcomponents are there-circulatingdiodeand theLM25005 regulatorIC.The easiestmethod todeterminethepower dissipatedwithintheLM25005 istomeasure thetotalconversionlosses (Pin– Pout)then subtractthe power lossesinthe Schottkydiode,outputinductorand snubber resistor.An approximationfortheSchottkydiodelossisP = (1-D)x Ioutx Vfwd.An approximationfortheoutputinductor power isP = IOUT 2 x R x 1.1,where R istheDC resistanceoftheinductorand the1.1factorisan approximation fortheac losses.Ifa snubberisused,thepower losscan be estimatedwithan oscilloscopeby observationof theresistorvoltagedropatbothturn-onand turn-offtransitions.The regulatorhas an exposed thermalpad toaid power dissipation.Adding severalviasunder the deviceto the ground planewillgreatlyreduce the regulator junctiontemperature.Selectinga diodewithan exposed pad willaidthepower dissipationofthediode. 5V,2.5A Demo Board BillofMaterials ITEM PART NUMBER DESCRIPTION VALUE C 1 C4532X7R2A225M CAPACITOR, CER, TDK 2.2µ,100V C 2 C4532X7R2A225M CAPACITOR, CER, TDK 2.2µ,100V C 3 C0805C331G1GAC CAPACITOR, CER, KEMET 330p,100V C 4 C2012X7R2A103K CAPACITOR, CER, TDK 0.01µ,100V C 5 C2012X7R2A103K CAPACITOR, CER, TDK 0.01µ,100V C 6 OPEN NOT USED C 7 C2012X7R2A223K CAPACITOR, CER, TDK 0.022µ,100V C 8 C2012X7R1C474M CAPACITOR, CER, TDK 0.47µ,16V C 9 C3225X7R1C226M CAPACITOR, CER, TDK 22µ,16V C 10 EEFHE0J151R CAPACITOR, SP, PANASONIC 150µ,6.3V C 11 C0805C331G1GAC CAPACITOR, CER, KEMET 330p,100V C 12 OPEN NOT USED D 1 CSHD6-60C DIODE, 60V,CENTRAL 6CWQ10FN DIODE, 100V,IR (D1-ALT) L 1 DR127-330 INDUCTOR, COOPER 33µH R 1 OPEN NOT USED R 2 OPEN NOT USED R 3 CRCW08052102F RESISTOR 21K R 4 CRCW08054992F RESISTOR 49.9K R 5 CRCW08055111F RESISTOR 5.11K R 6 CRCW08051651F RESISTOR 1.65K R 7 CRCW2512100J RESISTOR 10,1W U 1 LM25005 REGULATOR, TEXAS INSTRUMENTS
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www.ti.com SNVS411C –JANUARY 2006–REVISED MARCH 2013 PCB Layout Figure21. Component Side Figure22. SolderSide Figure23. Silkscreen Copyright© 2006–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 21 ProductFolderLinks:LM25005
SNVS411C –JANUARY 2006–REVISED MARCH 2013 www.ti.com
REVISION HISTORY
Changes from RevisionB (March 2013)toRevisionC Page
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www.ti.com 1-Nov-2013 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 LM25005MH NRND HTSSOP PWP 20 73 TBD Call TI Call TI -40 to 125 LM25005 MH LM25005MH/NOPB ACTIVE HTSSOP PWP 20 73 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM25005 MH LM25005MHX/NOPB ACTIVE HTSSOP PWP 20 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM25005 MH (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. (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
www.ti.com 1-Nov-2013 Addendum-Page 2 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 23-Sep-2013 Pack Materials-Page 1
*All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM25005MHX/NOPB HTSSOP PWP 20 2500 367.0 367.0 35.0 PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 Pack Materials-Page 2
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