LMD18245

LMD18245 3A, 55V DMOS Full-Bridge Motor Driver datasheet (Rev. E)

Document overview

• Manufacturer or author: Texas Instruments, Incorporated [SNVS110,E]
• PDF pages: 30

Technical content

www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 LMD182453A,55VDMOS Full-BridgeMotorDriver Check forSamples: LMD18245 1FEATURES DESCRIPTION The LMD18245 full-bridgepower amplifier 2• DMOS Power Stage Rated at55V and 3A incorporatesallthe circuitblocksrequiredto driveContinuous and controlcurrentin a brushed type DC motor or• Low R DS(ON) ofTypically0.3Ω per Power one phase of a bipolarsteppermotor.The multi- Switch technology process used to build the device combines bipolarand CMOS controland protection• InternalClamp Diodes circuitrywith DMOS power switcheson the same• Low-loss CurrentSensing Method monolithicstructure.The LMD18245 controlsthe• Digitalor Analog ControlofMotor Current motorcurrentviaa fixedoff-timechoppertechnique.

• TTL and CMOS Compatible Inputs An all DMOS H-bridge power stage delivers
• Thermal Shutdown (OutputsOff)atTJ = 155°C continuousoutputcurrentsup to 3A (6A peak) at supply voltagesup to 55V. The DMOS power• OvercurrentProtection switchesfeaturelow R DS(ON) forhighefficiency,and a• No Shoot-Through Currents diodeintrinsictotheDMOS body structureeliminates• 15-leadPackage thediscretediodestypicallyrequiredtoclamp bipolar power stages. APPLICATIONS An innovativecurrentsensingmethod eliminatesthe
• Full,Halfand MicrostepStepperMotor Drives power lossassociatedwitha sense resistorinseries withthe motor.A four-bitdigital-to-analogconverter• StepperMotor and Brushed DC Motor Servo (DAC) providesa digitalpathforcontrollingthemotorDrives current,and, by extension,simplifiesimplementation• Automated Factory,Medicaland Office of full,halfand microstepsteppermotor drives.ForEquipment higherresolutionapplications,an externalDAC can be used. Pleasebe aware thatan importantnoticeconcerningavailability,standardwarranty,and use incriticalapplicationsof Texas Instrumentssemiconductorproductsand disclaimerstheretoappearsattheend ofthisdatasheet. 2Alltrademarksarethepropertyoftheirrespectiveowners. PRODUCTION DATA informationiscurrentas ofpublicationdate. Copyright© 1998–2013,Texas InstrumentsIncorporatedProductsconform to specificationsper the terms of the Texas Instrumentsstandardwarranty.Productionprocessingdoes not necessarilyincludetestingofallparameters.

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com FunctionalBlock and Connection Diagram 15-LeadTO-220 Power Package (NDL) Figure1. FunctionalBlock Diagram Connection Diagram Figure2. Top View 15-Lead Package TO-220 Power Package See Package Number NDL0015A

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 PinoutDescriptions (See FunctionalBlockand ConnectionDiagrams) Pin 1,OUT 1:Outputnode ofthefirsthalfH-bridge. Pin 2,COMP OUT: Outputofthecomparator.IfthevoltageatCS OUT exceeds thatprovidedby theDAC, the comparatortriggersthemonostable. Pin 3, RC: Monostabletimingnode. A parallelresistorcapacitornetworkconnectedbetween thisnode and groundsetsthemonostabletimingpulseatabout1.1RC seconds. Pin 5,PGND: Ground returnnode ofthepower bridge.Bond wires(internaI)connectPGND tothetabofthe TO-220 package. Pins 4 and 6 through 8, M4 through M1: Digitalinputsof the DAC. These inputsmake up a four-bitbinary number withM4 as themost significantbitorMSB. The DAC providesan analogvoltagedirectlyproportionalto thebinarynumber appliedatM4 throughM1. Pin 9,VCC :Power supplynode. Pin 10,BRAKE: Brake logicinput.PullingtheBRAKE inputlogic-highactivatesbothsourcingswitchesofthe power bridge— effectivelyshortingtheload.See SWITCH CONTROL LOGIC TRUTH TABLE (1).Shortingthe loadinthismanner forcestheloadcurrenttorecirculateand decay tozero. Pin 11,DIRECTION: Directionlogicinput.The logiclevelatthisinputdictatesthedirectionofcurrentflowinthe load.See SWITCH CONTROL LOGIC TRUTH TABLE (1). Pin 12,SGND: Ground returnnode ofallsignallevelcircuits. Pin 13,CS OUT: Outputofthecurrentsense amplifier.The currentsense amplifiersources250 μA (typical)per ampere oftotalforwardcurrentconductedby theuppertwo switchesofthepower bridge. Pin 14,DAC REF: VoltagereferenceinputoftheDAC. The DAC providesan analogvoltageequaltoVDAC REF × D/16,where D isthedecimalequivalent(0–15)ofthebinarynumber appliedatM4 throughM1. Pin 15,OUT 2:Outputnode ofthesecond halfH-bridge. SWITCH CONTROL LOGIC TRUTH TABLE (1) BRAKE DIRECTION MONO ActiveSwitches H X X Source1,Source2 L H L Source2 L H H Source2,Sink1 L L L Source1 L L H Source1,Sink2 (1) X = don'tcare.MONO istheoutputofthemonostable. (1) X = don'tcare.MONO istheoutputofthemonostable. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com These deviceshave limitedbuilt-inESD protection.The leadsshouldbe shortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamage totheMOS gates. AbsoluteMaximum Ratings (1)(2) DC Voltageat: OUT 1,VCC ,and OUT 2 +60V COMP OUT, RC, M4, M3, M2, M1, BRAKE, +12V DIRECTION, CS OUT, and DAC REF DC VoltagePGND toSGND ±400mV ContinuousLoad Current 3A Peak Load Current(3) 6A JunctionTemperature(TJ(max)) +150°C Power Dissipation(4): TO-220 (TA = 25°C, InfiniteHeatsink) 25W TO-220 (TA = 25°C, FreeAir) 3.5W ESD Susceptibility(5) 1500V StorageTemperatureRange (TS) −40°C to+150°C Lead Temperature(Soldering,10 seconds) 300°C (1) AbsoluteMaximum Ratingsindicatelimitsbeyond whichdamage tothedevicemay occur.Electricalspecificationsdo notapplywhen operatingthedeviceoutsidetheratedOperatingConditions. (2) IfMilitary/Aerospacespecifieddevicesarerequired,pleasecontacttheTexas InstrumentsSalesOffice/Distributorsforavailabilityand specifications. (3) Unlessotherwisestated,loadcurrentsarepulseswithwidthslessthan2 ms and dutycycleslessthan5%. (4) The maximum allowablepower dissipationatany ambienttemperatureisPMax = (125− TA)/θJA,where 125°C isthemaximum junction temperatureforoperation,TA istheambienttemperaturein°C, and θJAisthejunction-to-ambientthermalresistancein°C/W. Exceeding Pmax voidstheElectricalSpecificationsby forcingTJabove 125°C. Ifthejunctiontemperatureexceeds155°C, internalcircuitrydisables thepower bridge.When a heatsinkisused,θJAisthesum ofthejunction-to-casethermalresistanceofthepackage,θJC,and thecase- to-ambientthermalresistanceoftheheatsink. (5) ESD ratingisbased on thehuman body model of100 pF dischargedthrougha 1.5kΩ resistor.M1, M2, M3 and M4, pins8,7,6 and 4 areprotectedto800V. OperatingConditions(1) TemperatureRange (TJ) (2) −40°C to+125°C SupplyVoltageRange (VCC ) +12V to+55V CS OUT VoltageRange 0V to+5V DAC REF VoltageRange 0V to+5V MONOSTABLE PulseRange 10 μs to100 ms (1) AbsoluteMaximum Ratingsindicatelimitsbeyond whichdamage tothedevicemay occur.Electricalspecificationsdo notapplywhen operatingthedeviceoutsidetheratedOperatingConditions. (2) The maximum allowablepower dissipationatany ambienttemperatureisPMax = (125− TA)/θJA,where 125°C isthemaximum junction temperatureforoperation,TA istheambienttemperaturein°C, and θJAisthejunction-to-ambientthermalresistancein°C/W. Exceeding Pmax voidstheElectricalSpecificationsby forcingTJabove 125°C. Ifthejunctiontemperatureexceeds155°C, internalcircuitrydisables thepower bridge.When a heatsinkisused,θJAisthesum ofthejunction-to-casethermalresistanceofthepackage,θJC,and thecase- to-ambientthermalresistanceoftheheatsink.

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 ElectricalCharacteristics(1) The followingspecificationsapplyforVCC = +42V, unlessotherwisestated.Boldfacelimitsapplyover theoperating temperaturerange,−40°C ≤ TJ ≤ +125°C. AllotherlimitsapplyforTA = TJ = 25°C. Typical (2) Limit (2) UnitsSymbol Parameter Conditions (Limits) ICC QuiescentSupplyCurrent DAC REF = 0V,VCC = +20V 8 mA 15 mA (max) POWER OUTPUT STAGE R DS(ON) SwitchON Resistance ILOAD = 3A 0.3 0.4 Ω (max) 0.6 Ω (max) ILOAD = 6A 0.3 0.4 Ω (max) 0.6 Ω (max) VDIODE Body DiodeForwardVoltage IDIODE = 3A 1.0 V

1.5 V(max)

Trr DiodeReverseRecoveryTime IDIODE = 1A 80 ns Q rr DiodeReverseRecoveryCharge IDIODE = 1A 40 nC tD(ON) OutputTurnON DelayTime SourcingOutputs ILOAD = 3A 5 μs SinkingOutputs ILOAD = 3A 900 ns tD(OFF) OutputTurnOFF DelayTime SourcingOutputs ILOAD = 3A 600 ns SinkingOutputs ILOAD = 3A 400 ns tON OutputTurnON SwitchingTime SourcingOutputs ILOAD = 3A 40 μs SinkingOutputs ILOAD = 3A 1 μs tOFF OutputTurnOFF SwitchingTime SourcingOutputs ILOAD = 3A 200 ns SinkingOutputs ILOAD = 3A 80 ns tpw Minimum InputPulseWidth Pins10 and 11 2 μs tDB Minimum Dead Band (3) 40 ns CURRENT SENSE AMPLIFIER CurrentSense Output ILOAD = 1A (4) 200 μA (min) 250 175 μA (min) 300 μA (max) 325 μA (max) CurrentSense LinearityError 0.5A≤ ILOAD ≤ 3A (4) ±6 % ±9 %(max) CurrentSense Offset ILOAD = 0A 5 μA 20 μA (max) (1) Unlessotherwisestated,loadcurrentsarepulseswithwidthslessthan2 ms and dutycycleslessthan5%. (2) Alllimitsare100% productiontestedat25°C. TemperatureextremelimitsareensuredviacorrelationusingacceptedSQC (Statistical QualityControl)methods.Alllimitsareused tocalculateAOQL (AverageOutgoingQualityLevel).TypicalsareatTJ = 25°C and representthemost likelyparametricnorm. (3) AsymmetricturnOFF and ON delaytimesand switchingtimesensurea switchturnsOFF beforetheotherswitchinthesame halfH- bridgebeginstoturnON (preventingmomentary shortcircuitsbetween thepower supplyand ground).The transitionalperiodduring whichbothswitchesareOFF iscommonly referredtoas thedead band. (4) (ILOAD ,ISENSE )datapointsaretakenforloadcurrentsof0.5A,1A,2A and 3A.The currentsense gainisspecifiedas ISENSE /ILOAD forthe 1A datapoint.The currentsense linearityisspecifiedas theslopeofthelinebetween the0.5Aand 1A datapointsminus theslopeof thelinebetween the2A and 3A datapointsalldividedby theslopeofthelinebetween the0.5Aand 1A datapoints. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com ElectricalCharacteristics(1)(continued) The followingspecificationsapplyforVCC = +42V, unlessotherwisestated.Boldfacelimitsapplyover theoperating temperaturerange,−40°C ≤ TJ ≤ +125°C. AllotherlimitsapplyforTA = TJ = 25°C. Typical (2) Limit (2) UnitsSymbol Parameter Conditions (Limits) DIGITAL-TO-ANALOG CONVERTER (DAC) Resolution 4 Bits(min) Monotonicity 4 Bits(min) TotalUnadjustedError 0.125 0.25 LSB (max)

0.5 LSB (max)

IREF DAC REF InputCurrent DAC REF = +5V −0.5 μA ±10 μA (max) COMPARATOR AND MONOSTABLE ComparatorHighOutputLevel 6.27 V ComparatorLow OutputLevel 88 mV ComparatorOutputCurrent Source 0.2 mA Sink 3.2 mA tDELAY MonostableTurnOFF Delay (5) 1.2 μs 2.0 μs (max) PROTECTION AND PACKAGE THERMAL RESISTANCES UndervoltageLockout,VCC 5 V (min)

8 V (max)

TJSD Shutdown Temperature,TJ 155 °C Package ThermalResistances θJC Junction-to-Case,TO-220 1.5 °C/W θJA Junction-to-Ambient,TO-220 35 °C/W LOGIC INPUTS VIL Low LevelInputVoltage −0.1 V (min)

0.8 V (max)

VIH HighLevelInputVoltage 2 V (min)

12 V (max)

IIN InputCurrent VIN = 0V or12V ±10 μA (max) (5) TurnOFF delay,tDELAY ,isdefinedas thetimefromthevoltageattheoutputofthecurrentsense amplifierreachingtheDAC output voltagetothelowerDMOS switchbeginningtoturnOFF. WithVCC = 32V,DIRECTION high,and 200Ω connectedbetween OUT1 and VCC ,thevoltageatRC isincreasedfrom0V to5V at1.2V/μs,and tDELAY ismeasured as thetimefromthevoltageatRC reaching2V to thetimethevoltageatOUT 1 reaches3V.

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 TypicalPerformance Characteristics RDS(ON) vs Temperature RDS(ON) vs Load Current Figure3. Figure4. RDS(ON) vs Supply Voltage CurrentSense Output vs Load Current Figure5. Figure6. Supply Currentvs Supply Voltage Supply Currentvs Temperature Figure7. Figure8. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com FUNCTIONAL DESCRIPTIONS TYPICAL OPERATION OF A CHOPPER AMPLIFIER Chopper amplifiersemploy feedbackdrivenswitchingofa power bridgetocontroland limitcurrentinthewinding ofa motor(Figure9).The bridgeconsistsoffoursolidstatepower switchesand fourdiodesconnectedinan H configuration.Controlcircuitry(notshown) monitorsthewindingcurrentand compares ittoa threshold.Whilethe windingcurrentremainslessthan the threshold,a sourceswitchand a sinkswitchinoppositehalvesof the bridgeforcethe supplyvoltageacrossthe winding,and the windingcurrentincreasesrapidlytowardsVCC /R (Figure9a and Figure9d ).As thewindingcurrentsurpassesthethreshold,thecontrolcircuitryturnsOFF the sinkswitchfora fixedperiodor off-time.Duringthe off-time,the sourceswitchand the oppositeupper diode shortthe winding,and the windingcurrentrecirculatesand decays slowlytowards zero (Figure9b and Figure9e ).At theend oftheoff-time,thecontrolcircuitryturnsback ON thesinkswitch,and thewindingcurrent againincreasesrapidlytowardsVCC /R (Figure9a and Figure9d again).The above sequence repeatstoprovide a currentchoppingactionthatlimitsthewindingcurrenttothethreshold(Figure9g ).Chopping onlyoccursifthe windingcurrentreachesthethreshold.Duringa change inthedirectionofthewindingcurrent,thediodesprovide a decay pathfortheinitialwindingcurrent(Figure9c and Figure9f).Sincethebridgeshortsthewindingfora fixedperiod,thistypeofchopperamplifieriscommonly referredtoas a fixedoff-timechopper. (a) (b) (c) (d)

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 (e) (f) (g) Figure9.Chopper AmplifierChopping States:FullVCC AppliedAcross theWinding (a)and (d),Shorted Winding (b)and (e),Winding CurrentDecays During a Change intheDirectionoftheWinding Current(c) and (f),and theChopped Winding Current(g) THE LMD18245 CHOPPER AMPLIFIER The LMD18245 incorporatesallthecircuitblocksneeded toimplementa fixedoff-timechopperamplifier.These blocksinclude:an allDMOS, fullH-bridgewithclamp diodes,an amplifierforsensingthe load current,a comparator,a monostable,and a DAC fordigitalcontrolofthechoppingthreshold.Alsoincorporatedare logic, levelshiftingand driveblocksfordigitalcontrolofthedirectionoftheloadcurrentand braking. THE H-BRIDGE The power stageconsistsoffourDMOS power switchesand associatedbody diodesconnectedinan H-bridge configuration(Figure10 ). The timeconstanttochargeordischargeany inductor,inthiscase themotorwindings,isdefinedas: τ = L/R where

• L isthewindinginductance
• R isthesum oftheseriesresistanceinthecurrentpathincludingthewindingresistance (1) TurningON a sourceswitchand a sinkswitchinoppositehalvesofthebridgeforcesthefullsupplyvoltageless the switchdrops (Ix R DS(ON) ) acrossthe motor winding.While the bridgeremains in thisstate,the winding currentincreasesexponentiallytowardsa limitdictatedby thesupplyvoltage,theswitchdrops(Ix R DS(ON) ),and the windingresistance.However, the windingcurrentexponentialrateof increasewillend when the current choppingcircuitrybecomes active. SubsequentlyturningOFF thesinkswitchcauses a voltagetransientthatforwardbiasesthebody diodeofthe othersourceswitch.The diodeclamps thetransientatone diodedropabove thesupplyvoltageand providesan alternativecurrentpath.While the bridgeremains in thisstate,itessentiallyshortsthe winding,the winding currentrecirculatesand decaysexponentiallytowardszeroata ratethatisdefinedby theL/R timeconstant. Duringa change inthedirectionofthewindingcurrent,boththeswitchesand thebody diodesprovidea decay pathfortheinitialwindingcurrent(Figure11 ). Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com Duringactualmotoroperationtherearemany variablesthatcan effectthemotorwindingmagneticbehaviorand performance.Resonance, eddy currents,friction,motor loading,damping, temperaturecoefficientsof the windings,areonlya few.These areallissuesthatarebeyond thescope ofthethisdatasheet. Figure10. The DMOS H-Bridge

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 Figure11. Decay Paths forInitialWinding CurrentDuring a Change intheDirectionoftheWinding Current THE CURRENT SENSE AMPLIFIER Many transistorcellsinparallelmake up the DMOS power switches.The currentsense amplifier(Figure12 ) uses a smallfractionofthecellsofbothupperswitchestoprovidea unique,low-lossmeans forsensingtheload current.Inpractice,each upperswitchfunctionsas a 1x sense deviceinparallelwitha 4000x power device.The currentsense amplifierforcesthevoltageatthesourceofthesense devicetoequalthatatthesourceofthe power device;thus,the devicesshare the totaldraincurrentin proportionto the 1:4000 cellratio.Only the currentflowingfrom draintosource,theforwardcurrent,registersattheoutputofthecurrentsense amplifier. The currentsense amplifier,therefore,sources250 μA per ampere of totalforwardcurrentconductedby the uppertwo switchesofthepower bridge. The sense currentdevelopsa potentialacrossR Sthatisproportionaltotheloadcurrent;forexample,perampere ofloadcurrent,thesense currentdevelopsone voltacrossa 4 kΩ resistor(theproductof250 μA per ampere and 4 kΩ).Sincechoppingoftheloadcurrentoccursas thevoltageatCS OUT surpassesthethreshold(the DAC outputvoltage),R S setsthegainofthechopperamplifier;forexample,a 2 kΩ resistorsetsthegainattwo amperes ofloadcurrentpervoltofthethreshold(thereciprocaloftheproductof250 μA perampere and 2 kΩ). A quarterwattresistorsuffices.A low valuecapacitorconnectedinparallelwithR S filterstheeffectsofswitching noisefromthecurrentsense signal. Whilethespecifiedmaximum DC voltagecomplianceatCS OUT is12V, thespecifiedoperatingvoltagerangeat CS OUT is0V to5V. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com THE DIGITAL-TO-ANALOG CONVERTER (DAC) The DAC setsthethresholdvoltageforchoppingatVDAC REF × D/16,where D isthedecimalequivalent(0–15)of thebinarynumber appliedatM4 throughM1, thedigitalinputsoftheDAC. M4 istheMSB ormost significantbit. Forapplicationsthatrequirehigherresolution,an externalDAC can drivetheDAC REF input.Whilethespecified maximum DC voltagecomplianceatDAC REF is12V, thespecifiedoperatingvoltagerangeatDAC REF is0V to5V. THE COMPARATOR, MONOSTABLE AND WINDING CURRENT THRESHOLD FOR CHOPPING As thevoltageatCS OUT surpassesthatattheoutputoftheDAC, thecomparatortriggersthemonostable,and themonostable,once triggered,providesa timingpulsetothecontrollogic.Duringthetimingpulse,thepower bridgeshortsthe motor winding,causingcurrentinthe windingto recirculateand decay slowlytowardszero (Figure9b and Figure9e again).A parallelresistor-capacitornetworkconnectedbetween RC (pin#3) and groundsetsthetimingpulseoroff-timeatabout1.1RC seconds. Chopping ofthewindingcurrentoccursas thevoltageatCS OUT exceeds thatattheoutputoftheDAC; so choppingoccursata windingcurrentthresholdofabout (VDAC REF × D/16)÷ ((250× 10−6)× R S))amperes. (2) The R S valuerequiredtosetthewindingcurrentthresholdatthemaximum ratedcurrentoftheLMD18245, with D = 15 and VDAC REF of5.00Vwouldbe: The resultingtypicalDAC programmablecurrentlimitvalues,fordifferentvaluesofR S,wouldbe: Table1.D toA winding currentthresholdsforVREF DAC = 5.00V R S = R S = R S =D 18.75kΩ 9.375kΩ 6.250kΩ 0 0.00A 0.00A 0.00A 1 0.07A 0.13A 0.20A 2 0.13A 0.27A 0.40A 3 0.20A 0.40A 0.60A 4 0.27A 0.53A 0.80A 5 0.33A 0.67A 1.00A 6 0.40A 0.80A 1.20A 7 0.47A 0.93A 1.40A 8 0.53A 1.07A 1.60A 9 0.60A 1.20A 1.80A 10 0.67A 1.33A 2.00A 11 0.73A 1.47A 2.20A 12 0.80A 1.60A 2.40A 13 0.87A 1.73A 2.60A 14 0.93A 1.87A 2.80A 15 1.00A 2.00A 3.00A

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 Figure12. The Source Switches ofthePower Bridgeand theCurrentSense Amplifier ApplicationsInformation POWER SUPPLY BYPASSING Step changes incurrentdrawn fromthepower supplyoccurrepeatedlyduringnormaloperationand may cause largevoltagespikesacrossinductanceinthepower supplyline.Care must be takentolimitvoltagespikesat VCC tolessthanthe60V AbsoluteMaximum Rating.At a change inthedirectionoftheloadcurrent,theinitial loadcurrenttendstoraisethevoltageatthepower supplyrail(Figure11) again.Currenttransientscaused by thereverserecoveryoftheclamp diodestendtopulldown thevoltageatthepower supplyrail. Bypassingthe power supplylineat VCC isrequiredto protectthe deviceand minimizethe adverseeffectsof normaloperationon thepower supplyrail.Usingbotha 1 μF highfrequencyceramiccapacitorand a large-value aluminum electrolyticcapacitorishighlyrecommended. A valueof 100 μF per ampere of loadcurrentusually sufficesforthealuminum electrolyticcapacitor.Both capacitorsshouldhave shortleadsand be locatedwithin one halfinchofVCC . OVERCURRENT PROTECTION Ifthe forwardcurrentineithersourceswitchexceeds a 12A threshold,internalcircuitrydisablesboth source switches,forcinga rapiddecay ofthefaultcurrent(Figure13).Approximately3 μs afterthefaultcurrentreaches zero,the devicerestarts.Automaticrestartallowsan immediate returnto normal operationonce the fault conditionhas been removed.Ifthefaultpersists,thedevicewillbegincyclingintoand outofthermalshutdown. Switchinglargefaultcurrentsmay cause potentiallydestructivevoltagespikesacrossinductanceinthepower supplyline;therefore,thepower supplylinemust be properlybypassed atVCC forthemotordrivertosurvivean extendedovercurrentfault. Inthecase ofa lockedrotor,theinductanceofthewindingtendstolimittherateofchange ofthefaultcurrentto a valueeasilyhandledby the protectioncircuitry.In the case of a low inductanceshortfrom eitheroutputto groundorbetween outputs,thefaultcurrentcouldsurgepastthe12A shutdown threshold,forcingthedeviceto dissipatea substantialamount ofpower forthebriefperiodrequiredtodisablethesourceswitches.Because the faultpower must be dissipatedby onlyone sourceswitch,a shortfrom outputtoground representstheworst case fault.Any overcurrentfaultispotentiallydestructive,especiallywhileoperatingwithhighsupplyvoltages (≥30V),so precautionsare inorder.SinkingVCC forheatwith1 squareinchof1 ounce copperon theprinted circuitboardishighlyrecommended. The sinkswitchesarenotinternallyprotectedagainstshortstoVCC . Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com THERMAL SHUTDOWN Internalcircuitrysenses thejunctiontemperaturenear thepower bridgeand disablesthebridgeifthejunction temperatureexceeds about155°C. When thejunctiontemperaturecoolspasttheshutdown threshold(lowered by a slighthysteresis),thedeviceautomaticallyrestarts. UNDERVOLTAGE LOCKOUT Internalcircuitrydisablesthepower bridgeifthepower supplyvoltagedropsbelow a rough thresholdbetween 8V and 5V.Shouldthepower supplyvoltagethenexceed thethreshold,thedeviceautomaticallyrestarts. Trace:FaultCurrentat5A/div Horizontal:20 μs/div Figure13. FaultCurrentwithVCC = 30V,OUT 1 Shorted toOUT 2,and CS OUT Grounded

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 The TypicalApplication Figure14 shows thetypicalapplication,thepower stageofa chopperdriveforbipolarsteppermotors.The 20 kΩ resistorand 2.2nF capacitorconnectedbetween RC and groundsettheoff-timeatabout48 μs,and the20 kΩ resistorconnectedbetween CS OUT and groundsetsthegainatabout200 mA pervoltofthethresholdfor chopping.Digitalsignalscontrolthe thresholdsforchopping,the directionsof the windingcurrents,and, by extension,thedrivetype(fullstep,halfstep,etc.).A μprocessororμcontrollerusuallyprovidesthedigitalcontrol signals. Figure14. TypicalApplicationCircuitforDrivingBipolarStepperMotors Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com ONE-PHASE-ON FULL STEP DRIVE (WAVE DRIVE) To make themotortakefullsteps,windingsA and B can be energizedinthesequence where A representswindingA energizedwithcurrentinone directionand A* representswindingA energized withcurrentintheoppositedirection.The motortakesone fullstepeach timeone windingisde-energizedand theotherisenergized.To make themotorstepintheoppositedirection,theorderoftheabove sequence must be reversed.Figure15 shows thewindingcurrentsand digitalcontrolsignalsfora wave driveapplicationofthe typicalapplicationcircuit. TWO-PHASE-ON FULL STEP DRIVE To make themotortakefullsteps,windingsA and B can alsobe energizedinthesequence and because bothwindingsareenergizedatalltimes,thissequence producesmore torquethanthatproduced withwave drive.The motor takesone fullstepateach change ofdirectionofeitherwindingcurrent.Figure16 shows the windingcurrentsand digitalcontrolsignalsforthisapplicationof the typicalapplicationcircuit,and Figure17 shows, fora singlephase,the windingcurrentand voltageat the outputof the associatedcurrent sense amplifier.

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M4 A, M3 A, M2 A, and M1 A M4 B, M3 B, M2 B, and M1 B FORWARD REVERSE 1 1 LMD18245 www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase B WindingCurrentat1A/div Horizontal:1 ms/div *500steps/second BRAKE A = BRAKE B = 0 Figure15. Winding Currentsand DigitalControlSignalsforOne-Phase-On Drive(Wave Drive) Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase B WindingCurrentat1A/div Horizontal:1 ms/div *500steps/second M4 A throughM1 A = M4 B throughM1 B = 1 BRAKE A = BRAKE B = 0 Figure16. Winding Currentsand DigitalControlSignalsforTwo-Phase-On Drive

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase A Sense Voltageat5V/div Horizontal:1 ms/div *500steps/second Figure17. Winding Currentand VoltageattheOutput oftheAssociatedCurrentSense Amplifier HALF STEP DRIVE WITHOUT TORQUE COMPENSATION To make themotortakehalfsteps,windingsA and B can be energizedinthesequence The motortakesone halfstepeach timethenumber ofenergizedwindingschanges.Itisimportanttonotethat althoughhalfsteppingdoublesthestepresolution,changingthenumber ofenergizedwindingsfromtwo toone decreases(one totwo increases)torqueby about40%, resultinginsignificanttorquerippleand possiblynoisy operation.Figure18 shows the windingcurrentsand digitalcontrolsignalsforthishalfstepapplicationof the typicalapplicationcircuit. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 19 ProductFolderLinks:LMD18245

M4 A, M3 A, M2 A, and M1 A M4 B, M3 B, M2 B, and M1 B FORWARD REVERSE 1 15 6 7 8 5 6 7 8 LMD18245 SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase B WindingCurrentat1A/div Horizontal:1 ms/div *500steps/second BRAKE A = BRAKE B = 0 Figure18. Winding Currentsand DigitalControlSignalsforHalfStep DrivewithoutTorque Compensation

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 HALF STEP DRIVE WITH TORQUE COMPENSATION To make the motor takehalfsteps,the windingscan alsobe energizedwithsinusoidalcurrents(Figure19). Controllingthewindingcurrentsinthefashionshown doublesthestepresolutionwithoutthesignificanttorque rippleofthepriordrivetechnique.The motor takesone halfstepeach timethelevelofeitherwindingcurrent changes.Halfstepdrivewithtorquecompensationismicrosteppingdrive.Along withtheobviousadvantageof increasedstepresolution,micro-steppingreducesboth fullsteposcillationsand resonancesthatoccuras the motor and loadcombinationisdrivenatitsnaturalresonantfrequencyor subharmonicsthereof.Both ofthese advantagesareobtainedby replacingfullstepswithburstsofmicrosteps.When compared tofullstepdrive,the motorrunssmootherand quieter. Table2 shows thelookuptableforthisapplicationofthetypicalapplicationcircuit.Dividing90°electricalperfull stepby two microstepsperfullstepyields45° electricalpermicrostep.α,therefore,increasesfrom0 to315° in incrementsof45°.Each full360° cyclecompriseseighthalfsteps.Rounding |cosα|tofourbitsgivesD A, the decimalequivalentofthebinarynumber appliedatM4 A throughM1 A.DIRECTION A controlsthepolarityofthe currentinwindingA.Figure19 shows thesinusoidalwindingcurrents. Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 21 ProductFolderLinks:LMD18245

M4 A, M2 A, M1 A, and M3 B M4 B, M2 B, M1 B, and M3 A LMD18245 SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase B WindingCurrentat1A/div Horizontal:2 ms/div *500steps/second BRAKE A = BRAKE B = 0 90° ELECTRICAL/FULL STEP ÷ 2 MICROSTEPS/FULL STEP = 45° ELECTRICAL/MICROSTEP Figure19. Winding Currentsand DigitalControlSignalsforHalfStep DrivewithTorque Compensation

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 Table2.Lookup TableforHalfStep DrivewithTorque Compensation α |cos(α)| D A DIRECTION A |sin(α)| D B DIRECTlON B | 0° 1 15 1 0 0 1 FORWARD 45° 0.707 11 1 0.707 11 1 ↓ 90° 0 0 0 1 15 1 135° 0.707 11 0 0.707 11 1 180° 1 15 0 0 0 0 ↑ 225° 0.707 11 0 0.707 11 0 REVERSE 270° 0 0 1 1 15 0 | 315° 0.707 11 1 0.707 11 0 REPEAT QUARTER STEP DRIVE WITH TORQUE COMPENSATION Figure20 shows thewindingcurrentsand lookuptablefora quarterstepdrive(fourmicrostepsperfullstep)with torquecompensation. Top Trace:Phase A WindingCurrentat1A/div BottomTrace:Phase B WindingCurrentat1A/div Horizontal:2ms/div *250steps/second 90° ELECTRICAL/FULL STEP ÷ 4 MICROSTEPS/FULL STEP = 22.5° ELECTRICAL/MICROSTEP Figure20. Winding CurrentsforQuarterStep DrivewithTorque Compensation Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 23 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com Table3.Lookup TableforQuarterStep DrivewithTorque Compensation (1) α |cos(α)| D A DIRECTION A |sin(α)| D B DIRECTION B | 0.0° 1 15 1 0 0 1 FORWARD 22.5° 0.924 14 1 0.383 6 1 ↓ 45.0° 0.707 11 1 0.707 11 1 67.5° 0.383 6 1 0.924 14 1 90.0° 0 0 0 1 15 1 112.5° 0.383 6 0 0.924 14 1 135.0° 0.707 11 0 0.707 11 1 157.5° 0.924 14 0 0.383 6 1 180.0° 1 15 0 0 0 0 202.5° 0.924 14 0 0.383 6 0 225.0° 0.707 11 0 0.707 11 0 247.5° 0.383 6 0 0.924 14 0 270.0° 0 0 1 1 15 0 ↑ 292.5° 0.383 6 1 0.924 14 0 REVERSE 315.0° 0.707 11 1 0.707 11 0 | 337.5° 0.924 14 1 0.383 6 0 REPEAT (1) BRAKE A = BRAKE B = 0

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www.ti.com SNVS110E –APRIL 1998–REVISED APRIL 2013 TestCircuitand SwitchingTime Definitions Copyright© 1998–2013,Texas InstrumentsIncorporated SubmitDocumentationFeedback 25 ProductFolderLinks:LMD18245

SNVS110E –APRIL 1998–REVISED APRIL 2013 www.ti.com

REVISION HISTORY

Changes from RevisionD (April2013)toRevisionE Page

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www.ti.com 11-Nov-2025 PACKAGING INFORMATION Orderable part number Status (1) Material type (2) Package | Pins Package qty | Carrier RoHS (3) Lead finish/ Ball material (4) MSL rating/ Peak reflow (5) Op temp (°C) Part marking (6) LMD18245T/NOPB Active Production TO-220 (NDL) | 15 20 | TUBE Yes SN Level-1-NA-UNLIM -40 to 125 LMD18245T LMD18245T/NOPB.B Active Production TO-220 (NDL) | 15 20 | TUBE - SN Level-1-NA-UNLIM -40 to 125 LMD18245T (1) Status: For more details on status, see our product life cycle. (2) Material type: When designated, preproduction parts are prototypes/experimental devices, and are not yet approved or released for full production. Testing and final process, including without limitation quality assurance, reliability performance testing, and/or process qualification, may not yet be complete, and this item is subject to further changes or possible discontinuation. If available for ordering, purchases will be subject to an additional waiver at checkout, and are intended for early internal evaluation purposes only. These items are sold without warranties of any kind. (3) RoHS values: Yes, No, RoHS Exempt. See the TI RoHS Statement for additional information and value definition. (4) Lead finish/Ball material: Parts may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two lines if the finish value exceeds the maximum column width. (5) MSL rating/Peak reflow: The moisture sensitivity level ratings and peak solder (reflow) temperatures. In the event that a part has multiple moisture sensitivity ratings, only the lowest level per JEDEC standards is shown. Refer to the shipping label for the actual reflow temperature that will be used to mount the part to the printed circuit board. (6) Part marking: There may be an additional marking, which relates to the logo, the lot trace code information, or the environmental category of the part. Multiple part markings will be inside parentheses. Only one part marking contained in parentheses and separated by a "~" will appear on a part. If a line is indented then it is a continuation of the previous line and the two combined represent the entire part marking for that device. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. Addendum-Page 1

PACKAGE MATERIALS INFORMATION www.ti.com 10-Aug-2026 TUBE L - Tube length T - Tube height W - Tube width B - Alignment groove width *All dimensions are nominal Device Package Name Package Type Pins SPQ L (mm) W (mm) T (µm) B (mm) LMD18245T/NOPB NDL TO-220 15 20 502 34 12192 0 LMD18245T/NOPB.B NDL TO-220 15 20 502 34 12192 0 Pack Materials-Page 1

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