Product Sample & Technical Tools & Support & Folder Buy Documents Software Community UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 UCx846/7 Current Mode PWM Controller 1 Features 3 Description • AutomaticFeedforwardCompensation The UC1846/7 family of control devices provides all 1 of the necessary features to implement fixed- • ProgrammablePulse-by-PulseCurrentLimiting frequency, current-mode control schemes while • AutomaticSymmetryCorrectioninPush-Pull maintaining a minimum external parts count. The Configuration superior performance of this technique can be • EnhancedLoadResponseCharacteristics measured in improved line regulation, enhanced load response characteristics, and a simpler, easier-to- • ParallelOperationCapabilityforModularPower design control loop. Topological advantages include Systems inherent pulse-by-pulse current limiting capability, • DifferentialCurrentSenseAmplifierwithWide automatic symmetry correction for push-pull CommonModeRange converters, and the ability to parallel power modules whilemaintainingequalcurrentsharing. • Double-PulseSuppression • 500-mA(Peak)Totem-poleOutputs Protection circuitry includes built-in undervoltage lockout and programmable current limit, in addition to • ±1%BandGapReference soft-start capability. A shutdown function is also • UndervoltageLockout available, which can initiate either a complete • Soft-StartCapability shutdown with automatic restart or latch the supply • ShutdownTerminal off. • 500-kHzOperation Other features include fully-latched operation, double- pulse suppression, deadline adjust capability, and a 2 Applications ±1%trimmedbandgapreference. • TelecommunicationPowerConverters The UC1846 features low outputs in the OFF state, while the UCx847 features high outputs in the OFF • IndustrialPowerConverters state. DeviceInformation(1) PARTNUMBER PACKAGE BODYSIZE(NOM) LCCC(20) 8.89mm×8.89mm UC1846 CDIP(16) 6.92mm×19.56mm PLCC(20) 8.96mm×8.96mm UC2846,UC3846 SOIC(16) 7.5mm×10.3mm PDIP(16) 6.35mm×19.3mm SOIC(16) 7.5mm×10.3mm UC2847,UC3847 PDIP(16) 6.35mm×19.3mm (1) For all available packages, see the orderable addendum at theendofthedatasheet. BlockDiagram VIN 15 180(cid:159) .1(cid:181)F 2 VREF VIN VC 13 2W .05(cid:181)F .0.50k5(cid:181)F 98 RT AOUT 11 68(cid:159) 1k 2N4150 11NN44224455 UES1402 200(cid:181)H VO CT C/S+ 4 100(cid:181)F 3.2k 5+E/AUCX846BOUT 14 68(cid:159) 1k 2N4150 1N4245 300(cid:181)F 3.2k 6 -E/A C/S- 3 .05(cid:181)F .5Q UES1402 7 COMP CS/SS 1 VREF .0015 68k SH-DN GND 1.5k 16 12 1k 3.6k 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectualpropertymattersandotherimportantdisclaimers.PRODUCTIONDATA.

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com Table of Contents 1 Features.................................................................. 1 7.4 DeviceFunctionalModes........................................10 2 Applications........................................................... 1 8 ApplicationandImplementation........................ 11 3 Description............................................................. 1 8.1 ApplicationInformation............................................11 4 RevisionHistory..................................................... 2 8.2 TypicalApplication .................................................11 5 PinConfigurationandFunctions......................... 3 9 PowerSupplyRecommendations...................... 15 6 Specifications......................................................... 4 10 Layout................................................................... 16 6.1 AbsoluteMaximumRatings......................................4 10.1 LayoutGuidelines.................................................16 6.2 ESDRatings..............................................................4 10.2 LayoutExample....................................................16 6.3 RecommendedOperatingConditions.......................4 11 DeviceandDocumentationSupport................. 17 6.4 ThermalInformation..................................................4 11.1 RelatedLinks........................................................17 6.5 ElectricalCharacteristics...........................................5 11.2 CommunityResources..........................................17 6.6 TypicalCharacteristics..............................................7 11.3 Trademarks...........................................................17 7 DetailedDescription.............................................. 8 11.4 ElectrostaticDischargeCaution............................17 7.1 Overview...................................................................8 11.5 Glossary................................................................17 7.2 FunctionalBlockDiagram.........................................8 12 Mechanical,Packaging,andOrderable Information........................................................... 17 7.3 FeatureDescription...................................................8 4 Revision History NOTE:Pagenumbersforpreviousrevisionsmaydifferfrompagenumbersinthecurrentversion. ChangesfromRevisionB(July2010)toRevisionC Page • AddedESDRatingstable,FeatureDescriptionsection,DeviceFunctionalModes,ApplicationandImplementation section,PowerSupplyRecommendationssection,Layoutsection,DeviceandDocumentationSupportsection,and Mechanical,Packaging,andOrderableInformationsection.................................................................................................. 1 • Removedsolderingtemperature ........................................................................................................................................... 4 ChangesfromRevisionA(February2002)toRevisionB Page • UpdatedBlockDiagram......................................................................................................................................................... 1 2 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 5 Pin Configuration and Functions JorN,DWPackages 16-PinCDIPorPDIP,SOIC TopView FNorFKPackages 20-PinPLCCorLCCC TopView PinFunctions PIN PLCC,LCC I/O DESCRIPTION DIL,SOICNO. NAME NO. 1 2 C/SSS I Currentlimit/soft-startprogramming 2 3 V O 5.1-Vreferencevoltageoutput REF 3 4 C/S– I Currentsensecomparatorinvertinginput 4 5 C/S+ I Currentsensecomparatornon-invertinginput 5 7 E/A+ I Erroramplifierinvertinginput 6 8 E/A– I Erroramplifierinvertinginput 7 9 COMP I/O ErroramplifieroutputandinputtothePWMcomparator 8 10 C I Oscillatorfrequencyprogrammingcapacitorpin T 9 12 C I Oscillatorfrequencyprogrammingresistorpin R 10 13 Sync I/O Synchronizationoutfrommastercontrollerorinputofslavecontroller 11 14 AOut O PWMdrivesignaloutputA,Pin11andP14arecomplementary 12 15 GND G Allsignalsarereferencedtothisnode 13 17 V I Biassupplyinputforoutputstage C 14 18 BOut O PWMdrivesignaloutputB,Pin11andP14arecomplementary 15 19 V I Biassupplyinput IN 16 20 Shutdown I Externalshutdownsignalinput — 1,6,11,16 N/C Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 3 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings overoperatingfree-airtemperaturerange(unlessotherwisenoted)(1) MIN MAX UNIT SupplyVoltage(Pin15) 40 V CollectorSupplyVoltage(Pin13) 40 V OutputCurrent,SourceorSink(Pins11,14) 500 mA AnalogInputs(Pins3,4,5,6,16) –0.3 +V V IN ReferenceOutputCurrent(Pin2) –30 mA SyncOutputCurrent(Pin10) –5 mA ErrorAmplifierOutputCurrent(Pin7) –5 mA SoftStartSinkCurrent(Pin1) 50 mA OscillatorChargingCurrent(Pin9) 5 mA PowerDissipationatT =25°C 1000 mW A PowerDissipationatT =25°C 2000 mW C Storagetemperature,T –65 150 °C stg (1) StressesbeyondthoselistedunderAbsoluteMaximumRatingsmaycausepermanentdamagetothedevice.Thesearestressratings only,whichdonotimplyfunctionaloperationofthedeviceattheseoranyotherconditionsbeyondthoseindicatedunderRecommended OperatingConditions.Exposuretoabsolute-maximum-ratedconditionsforextendedperiodsmayaffectdevicereliability. 6.2 ESD Ratings VALUE UNIT Human-bodymodel(HBM),perANSI/ESDA/JEDECJS-001(1) ±2500 V(ESD) Electrostaticdischarge Charged-devicemodel(CDM),perJEDECspecificationJESD22- V C101(2) ±1500 (1) JEDECdocumentJEP155statesthat500-VHBMallowssafemanufacturingwithastandardESDcontrolprocess. (2) JEDECdocumentJEP157statesthat250-VCDMallowssafemanufacturingwithastandardESDcontrolprocess. 6.3 Recommended Operating Conditions overoperatingfree-airtemperaturerange(unlessotherwisenoted) MIN NOM MAX UNIT VREFterminalexternalcapacitance 1 2.2 µF 6.4 Thermal Information UCx846/7 THERMALMETRIC(1) NorDW(PDIPor JorDW(CDIPor UNIT SOIC) SOIC) 16PINS 16PINS R Junction-to-ambientthermalresistance 41.8 73.1 °C/W θJA R Junction-to-case(top)thermalresistance 28.5 34.2 °C/W θJC(top) R Junction-to-boardthermalresistance 21.8 38.0 °C/W θJB ψ Junction-to-topcharacterizationparameter 13.0 7.7 °C/W JT ψ Junction-to-boardcharacterizationparameter 21.7 37.4 °C/W JB R Junction-to-case(bottom)thermalresistance N/A N/A °C/W θJC(bot) (1) Formoreinformationabouttraditionalandnewthermalmetrics,seetheSemiconductorandICPackageThermalMetricsapplication report,SPRA953. 4 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 6.5 Electrical Characteristics T =–55°Cto+125°CforUC1846/7;–40°Cto+85°CfortheUC2846/7;and0°Cto+70°CfortheUC3846/7;V =15V, A IN R =10k,C =4.7nF,T =T (unlessotherwisenoted) T T A J UC1846/7 UC3846/7 PARAMETER TESTCONDITIONS UC2846/7 UNIT MIN TYP MAX MIN TYP MAX REFERENCE OutputVoltage T =25°C,I =1mA 5.05 5.10 5.15 5.00 5.10 5.20 V J O LineRegulation V =8Vto40V 5 20 5 20 mV IN LoadRegulation I =1mAto10mA 3 15 3 15 mV L OverOperating TemperatureStability Range, (1) 0.4 0.4 mV/°C Line,Load,and TotalOutputVariation Temperature (1) 5.00 5.20 4.95 5.25 V 10Hz≤f≤10kHz,T OutputNoiseVoltage =25°C(1) J 100 100 µV T =125°C,1000 LongTermStability HJrs(1) 5 5 mV ShortCircuitOutputCurrent V =0V –10 –45 –10 –45 mA REF OSCILLATOR InitialAccuracy T =25°C 39 43 47 39 43 47 kHz J VoltageStability V =8Vto40V –1% 2% –1% 2% IN OverOperating TemperatureStability Range (1) –1% –1% SyncOutputHighLevel 3.9 4.35 3.9 4.35 V SyncOutputLowLevel 2.3 2.5 2.3 2.5 V SyncInputHighLevel Pin8=0V 3.9 3.9 V SyncInputLowLevel Pin8=0V 2.5 2.5 V SyncVoltage=3.9V, SyncInputCurrent 1.3 1.5 1.3 1.5 mA Pin8=0V ERRORAMPLIFIER InputOffsetVoltage 0.5 5 0.5 10 mV InputBiasCurrent –0.6 –1 –0.6 –2 µA InputOffsetCurrent 40 250 40 250 nA CommonModeRange V =8Vto40V 0 V -2V 0 V -2V V IN IN IN ΔV =1.2to3V,V OpenLoopVoltageGain O CM 80 105 80 105 dB =2V UnityGainBandwidth T =25°C(1) 0.7 1.0 0.7 1.0 MHz J V =0Vto38V, CMRR CM 75 100 75 100 dB V =40V IN PSRR V =8Vto40V 80 105 80 105 dB IN V =–15mVto-5V, OutputSinkCurrent ID 2 6 2 6 mA V =1.2V PIN7 V =15mVto-5V, OutputSourceCurrent ID –0.4 –0.5 –0.4 –0.5 mA V =2.5V PIN7 HighLevelOutputVoltage R =(Pin7)15kΩ 4.3 4.6 4.3 4.6 V L LowLevelOutputVoltage R =(Pin7)15kΩ 0.7 1 0.7 1 V L CURRENTSENSEAMPLIFIER V =0V,Pin1 AmplifierGain OPpIeNn3(2), (3) 2.5 2.75 3.0 2.5 2.75 3.0 V (1) Theseparameters,althoughensuredovertherecommendedoperatingconditions,arenot100%testedinproduction. (2) ParametermeasuredattrippointoflatchwithVPIN5=VREF,VPIN6=0V. (3) Amplifiergaindefinedas:G=ΔV /ΔV ;V =0to1.0V PIN7 PIN4 PIN4 Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 5 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com Electrical Characteristics (continued) T =–55°Cto+125°CforUC1846/7;–40°Cto+85°CfortheUC2846/7;and0°Cto+70°CfortheUC3846/7;V =15V, A IN R =10k,C =4.7nF,T =T (unlessotherwisenoted) T T A J UC1846/7 UC3846/7 PARAMETER TESTCONDITIONS UC2846/7 UNIT MIN TYP MAX MIN TYP MAX MaximumDifferentialInput Pin1Open (2);R L 1.1 1.2 1.1 1.2 V Signal(V -V ) (Pin7)=15kW PIN4 PIN3 V =0.5V,Pin7 InputOffsetVoltage OPpIeNn1(2) 5 25 5 25 mV CMRR V =1Vto12V 60 83 60 83 dB CM PSRR V =8Vto40V 60 84 60 84 dB IN V =0.5V,Pin7 InputBiasCurrent OPpIeNn1(2) –2.5 –10 –2.5 –10 µA V =0.5V,Pin7 InputOffsetCurrent OPpIeNn1(2) 0.08 1 0.08 1 µA InputCommonModeRange 0 V -3 0 V -3 V IN IN DelaytoOutputs T =25°C (1) 200 500 200 500 ns J CURRENTLIMITADJUST V =0V,V = CurrentLimitOffset 0PVIN,P3in7OpePnIN(24) 0.45 0.5 0.55 0.45 0.5 0.55 V V =V ,V InputBiasCurrent PIN5 REF PIN6 –10 –30 –10 –30 µA =0V SHUTDOWNTERMINAL ThresholdVoltage 250 350 400 250 350 400 mV InputVoltageRange 0 V 0 V V IN IN MinimumLatchingCurrent (4)3.0 1.5 3.0 1.5 mA (I ) PIN1 MaximumLatchingCurrent (5)1.5 0.8 1.5 0.8 mA (I ) PIN1 DelaytoOutputs T =25°C (1) 300 600 300 600 ns J OUTPUT Collector-EmitterVoltage 40 40 V CollectorLeakageCurrent V =40V (6) 200 200 µA C I =20mA 0.1 0.4 0.1 0.4 SINK OutputLowLevel V I =100mA 0.4 2.1 0.4 2.1 SINK I =20mA 13 13.5 13 13.5 SOURCE OutputHighLevel V I =100mA 12 13.5 12 13.5 SOURCE C =1nF,T =25°C RiseTime (1L) J 50 300 50 300 ns C =1nF,T =25°C FallTime (1L) J 50 300 50 300 ns UNDERVOLTAGELOCKOUT Start-UpThreshold 7.7 8.0 7.7 8.0 V ThresholdHysteresis 0.75 0.75 V TOTALSTANDBYCURRENT SupplyCurrent 17 21 17 21 mA (4) CurrentintoPin1ensuredtolatchcircuitinshutdownstate. (5) CurrentintoPin1ensurednottolatchcircuitinshutdownstate. (6) AppliestoUC1846/UC2846/UC3846onlyduetopolarityofoutputs. 6 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 6.6 Typical Characteristics Figure1.ErrorAmplifierGainandPhasevsFrequency Figure2.ErroramplifierOpen-LogicDCGainvsLoad Resistance Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 7 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 7 Detailed Description 7.1 Overview The UCx846/7 family of control devices provides the necessary features to implement off-line or DC-to-DC fixed- frequency, current-mode control schemes with a minimal external parts count. Internally implemented circuits include under-voltage lockout featuring start-up current less than 1 mA, a precision reference trimmed for accuracy at the error amplifier input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high-peak current. The output stage,suitablefordrivingeitherN-ChannelMOSFETsorbipolartransistorswitches,islowintheoffstate. 7.2 Functional Block Diagram 5.1-V VIN 15 REFERENCE 2 VREF REGULATOR 13 VC SYNC 10 UVLO LOCKOUT F/F Q 11 A OUT RT 9 T OSC Q UC1846 Output Stage CT 8 C/S- 3 COMP X3 + + S R UC1847 C/S+ 4 Q Output Inverted S 0.5 V 14 B OUT + 0.5 mA NI 5 12 GND + E/A INV 6 CURRENT LIMIT 1 ADJUST + 16 SHUTDOWN COMP 7 350 mV 6 k: 7.3 Feature Description 7.3.1 CurrentSenseAmplifier The current sense amplifier may be used in a variety of ways to sense peak switch current for comparison with an error voltage. Referring to Functional Block Diagram, maximum swing on the inverting input of the PWM comparator is limited to approximately 3.5 V by the internal regulated supply. Accordingly, for a fixed gain of 3, maximumdifferentialvoltagesmustbekeptbelow1.2Vatthecurrentsenseinputs. 8 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 Feature Description (continued) Asmall RC filter may be required in some applications to reduce switch transients. Differential input allows remote, noise free sensing. Figure3. CurrentSenseAmplifierConnection 7.3.2 Oscillator By implementing the oscillator using all NPN transistors, the UCx846/7 achieves excellent temperature stability andwaveformclarityatfrequenciesinexcessof1MHz. Referring to Figure 4, an external resistor R is used to generate a constant current into a capacitor C to T T produce a linear sawtooth waveform. Oscillator frequency may be approximated by selecting R and C such T T that: 2.2 f OSC R C T T (1) Figure4. OscillatorCircuit Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 9 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 7.4 Device Functional Modes 7.4.1 CurrentLimit One of the most attractive features of a current-mode converter is the ability to limit peak-switch currents on a pulse-by-pulsebasisbysimplylimitingtheerrorvoltagetoamaximumvalue. 7.4.2 Shutdown The shutdown circuit was designed to provide a fast acting general purpose shutdown port for use in implementing both protection circuitry and remote shutdown functions. The circuit may be divided into an input section consisting of a comparator with a 350-mV temperature compensated offset, and an output section consisting of a three transistor latch. Shutdown is accomplished by applying a signal greater than 350 mV to pin 16,causingtheoutputlatchtofire,andsettingthePWMlatchtoprovideanimmediatesignaltotheoutputs. 10 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validateandtesttheirdesignimplementationtoconfirmsystemfunctionality. 8.1 Application Information The UCx846/7 family of control devices provides all of the necessary features to implement fixed frequency, current mode control schemes while maintaining a minimum external parts count. The superior performance of this technique can be measured in improved line regulation, enhanced load response characteristics, and a simpler, easier to design control loop. Topological advantages include inherent pulse-by-pulse current limiting capability, automatic symmetry correction for push-pull converters. Protection circuitry includes undervoltage lockout and programmable current limit in addition to soft-start capability. A shutdown function is also available whichinitiateseitheracompleteshutdownwithautomaticrestartorlatchthesupplyoff. 8.2 Typical Application VIN 15 180(cid:159) .1(cid:181)F VIN 2W 2 13 VREF VC .05(cid:181)F .5k 11NN44224455 9 11 RT AOUT 2N4150 .005(cid:181)F 8 68(cid:159) 1k UES1402 200(cid:181)H VO CT C/S+ 4 UCX846 3.2k 100(cid:181)F 5 +E/A BOUT 14 68(cid:159) 1k 2N4150 1N4245 300(cid:181)F UES1402 3.2k 6 -E/A C/S- 3 .05(cid:181)F .5Q 7 COMP CS/SS 1 VREF .0015 68k SH-DN GND 1.5k 16 12 1k 3.6k Figure5. TypicalApplicationDiagram 8.2.1 DesignRequirements Table1showsthedesignparametersforthisapplication. Table1.DesignParameters DESIGNPARAMETER TARGETVALUE Typicalefficiency 85% Switchingfrequency 880kHz Pulsebypulsecurrentlimitthreshold 1A Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 11 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 8.2.2 DetailedDesignProcedure Thissectiondetailsthedesignprocedurebasedonthedesignrequirements. 8.2.2.1 DesignSwitchingFrequency Outputdeadtimeisdeterminedbytheexternalcapacitor,C ,accordingtotheformula: T “ ” « » ID Td(Ps) 145C (PF)« » T 3.6 « » ID(cid:16) «‹ RT(k:)»… where • ID=Oscillatordischargecurrentat25°C;typicallyis7.5. (2) ForlargevaluesofR :τd(μs) ≈145CT(μF). T Oscillatorfrequencyisapproximatedbytheformula: 2.2 fT(kHz)| (cid:11)R (k:)uC (PF)(cid:12) T T (3) 8.2.2.2 ErrorAmplifierOutputConfiguration Figure6. ErrorAmplifierOutputConfiguration 12 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 8.2.2.3 ParallelOperationConfiguration Figure7. ParallelOperation 8.2.2.4 DesignPulsebyPulseCurrentLimitThreshold R2VREF −0.5 R1+R2 Peak Current (IS) is determined by the formula:IS= 3RS Figure8. PulsebyPulseCurrentLimiting Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 13 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 8.2.2.5 Soft-StartandShutdown,RestartFunctionDesign Figure9. Soft-StartandShutdown,RestartFunctions 14 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 8.2.3 ApplicationCurves t=0.2ms/div outputresponse=20mV/div Figure10.ResponsivetoaStepLoadChangeof1A Figure11.SwitchCurrentShowingFluxBalancein UCX846/7 9 Power Supply Recommendations TheVINpowerterminalforthedevicerequirestheplacementoflowesrnoise-decouplingcapacitanceasdirectly as possible from the VIN terminal to the GND terminal. Ceramic capacitors with stable dielectric characteristics overtemperaturearerecommended,suchasX7Rorbetter. The VC power terminal for the device requires the placement of resistance as directly as possible from the VC terminaltotheVINterminal. Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 15 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 SLUS352C–JANUARY1997–REVISEDDECEMBER2015 www.ti.com 10 Layout 10.1 Layout Guidelines • Place a low ESR and ESL decoupling capacitor C in the 1-µF to 2.2-µF range, preferably ceramic, from REF VREFpintoGND. • The EA+ is a non-inverting input, the EA– is an inverting input and the COMP is the output of the error amplifier. Place resistor and capacitor series network between EA+ pin and COMP pin, and reduce the trace ofresistorandcapacitorseriesnetworkasmuchaspossible. • Place a low ESR and ESL capacitor C , preferably ceramic, from CT pin to GND, and place C close to T T UCx846/7asmuchaspossible. • PlacearesistorR fromRTpintoGND,andplaceR closetoUCx846/7asmuchaspossible. T T 10.2 Layout Example Vin 1 C/S SS SHUTDOWN 16 2 VREF VIN 15 3 C/S- BOUT 14 4 C/S+ VC 13 5 E/A+ GND 12 6 E/A- AOUT 11 7 COMP SYNC 10 8 CT RT 9 Figure12. UCx84xLayoutExample 16 SubmitDocumentationFeedback Copyright©1997–2015,TexasInstrumentsIncorporated ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

UC1846,UC1847,UC2846 UC2847,UC3846,UC3847 www.ti.com SLUS352C–JANUARY1997–REVISEDDECEMBER2015 11 Device and Documentation Support 11.1 Related Links The table below lists quick access links. Categories include technical documents, support and community resources,toolsandsoftware,andquickaccesstosampleorbuy. Table2.RelatedLinks TECHNICAL TOOLS& SUPPORT& PARTS PRODUCTFOLDER SAMPLE&BUY DOCUMENTS SOFTWARE COMMUNITY UC1846 Clickhere Clickhere Clickhere Clickhere Clickhere UC1847 Clickhere Clickhere Clickhere Clickhere Clickhere UC2846 Clickhere Clickhere Clickhere Clickhere Clickhere UC2847 Clickhere Clickhere Clickhere Clickhere Clickhere UC3846 Clickhere Clickhere Clickhere Clickhere Clickhere UC3847 Clickhere Clickhere Clickhere Clickhere Clickhere 11.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TIE2E™OnlineCommunity TI'sEngineer-to-Engineer(E2E)Community.Createdtofostercollaboration amongengineers.Ate2e.ti.com,youcanaskquestions,shareknowledge,exploreideasandhelp solveproblemswithfellowengineers. DesignSupport TI'sDesignSupport QuicklyfindhelpfulE2Eforumsalongwithdesignsupporttoolsand contactinformationfortechnicalsupport. 11.3 Trademarks E2EisatrademarkofTexasInstruments. Allothertrademarksarethepropertyoftheirrespectiveowners. 11.4 Electrostatic Discharge Caution Thesedeviceshavelimitedbuilt-inESDprotection.Theleadsshouldbeshortedtogetherorthedeviceplacedinconductivefoam duringstorageorhandlingtopreventelectrostaticdamagetotheMOSgates. 11.5 Glossary SLYZ022—TIGlossary. Thisglossarylistsandexplainsterms,acronyms,anddefinitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of thisdocument.Forbrowser-basedversionsofthisdatasheet,refertotheleft-handnavigation. Copyright©1997–2015,TexasInstrumentsIncorporated SubmitDocumentationFeedback 17 ProductFolderLinks:UC1846 UC1847 UC2846UC2847 UC3846 UC3847

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 PACKAGING INFORMATION Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) 5962-86806012A ACTIVE LCCC FK 20 1 TBD POST-PLATE N / A for Pkg Type -55 to 125 5962- 86806012A UC1846L/ 883B 5962-8680601EA ACTIVE CDIP J 16 1 TBD Call TI N / A for Pkg Type -55 to 125 5962-8680601EA UC1846J/883B UC1846J ACTIVE CDIP J 16 1 TBD Call TI N / A for Pkg Type -55 to 125 UC1846J UC1846J883B ACTIVE CDIP J 16 1 TBD Call TI N / A for Pkg Type -55 to 125 5962-8680601EA UC1846J/883B UC1846L883B ACTIVE LCCC FK 20 1 TBD POST-PLATE N / A for Pkg Type -55 to 125 5962- 86806012A UC1846L/ 883B UC2846DW ACTIVE SOIC DW 16 40 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 UC2846DW & no Sb/Br) UC2846DWG4 ACTIVE SOIC DW 16 40 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 UC2846DW & no Sb/Br) UC2846DWTR ACTIVE SOIC DW 16 2000 Green (RoHS NIPDAU Level-2-260C-1 YEAR -40 to 85 UC2846DW & no Sb/Br) UC2846J ACTIVE CDIP J 16 1 TBD Call TI N / A for Pkg Type -40 to 85 UC2846J UC2846N ACTIVE PDIP N 16 25 Green (RoHS NIPDAU N / A for Pkg Type -40 to 85 UC2846N & no Sb/Br) UC2846NG4 ACTIVE PDIP N 16 25 Green (RoHS NIPDAU N / A for Pkg Type -40 to 85 UC2846N & no Sb/Br) UC3846DW ACTIVE SOIC DW 16 40 Green (RoHS NIPDAU Level-2-260C-1 YEAR 0 to 70 UC3846DW & no Sb/Br) UC3846DWTR ACTIVE SOIC DW 16 2000 Green (RoHS NIPDAU Level-2-260C-1 YEAR 0 to 70 UC3846DW & no Sb/Br) UC3846DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS NIPDAU Level-2-260C-1 YEAR 0 to 70 UC3846DW & no Sb/Br) UC3846N ACTIVE PDIP N 16 25 Green (RoHS NIPDAU N / A for Pkg Type 0 to 70 UC3846N & no Sb/Br) UC3846NG4 ACTIVE PDIP N 16 25 Green (RoHS NIPDAU N / A for Pkg Type 0 to 70 UC3846N & no Sb/Br) Addendum-Page 1

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 Orderable Device Status Package Type Package Pins Package Eco Plan Lead/Ball Finish MSL Peak Temp Op Temp (°C) Device Marking Samples (1) Drawing Qty (2) (6) (3) (4/5) UC3847DW ACTIVE SOIC DW 16 40 Green (RoHS NIPDAU Level-2-260C-1 YEAR 0 to 70 UC3847DW & no Sb/Br) (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) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may reference these types of products as "Pb-Free". RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption. Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based flame retardants must also meet the <=1000ppm threshold requirement. (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release. In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis. OTHER QUALIFIED VERSIONS OF UC1846, UC2846, UC2846M, UC3846 : •Catalog: UC3846, UC2846 Addendum-Page 2

PACKAGE OPTION ADDENDUM www.ti.com 6-Feb-2020 •Enhanced Product: UC1846-EP, UC1846-EP •Military: UC2846M, UC1846 •Space: UC1846-SP, UC1846-SP NOTE: Qualified Version Definitions: •Catalog - TI's standard catalog product •Enhanced Product - Supports Defense, Aerospace and Medical Applications •Military - QML certified for Military and Defense Applications •Space - Radiation tolerant, ceramic packaging and qualified for use in Space-based application Addendum-Page 3

PACKAGE MATERIALS INFORMATION www.ti.com 6-May-2015 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1 Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant (mm) W1(mm) UC2846DWTR SOIC DW 16 2000 330.0 16.4 10.75 10.7 2.7 12.0 16.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 6-May-2015 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) UC2846DWTR SOIC DW 16 2000 367.0 367.0 38.0 PackMaterials-Page2

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