UC1853 UC2853 UC3853 High Power Factor Preregulator FEATURES DESCRIPTION • Complete8-pinPowerFactor The UC3853 provides simple, yet high performance active power factor Solution correction.Using the same control technique as the UC1854, this 8-pin de- vice exploits a simplified architecture and an internal oscillator to minimize • ReducedExternalComponents external component count. The UC3853 incorporates a precision multi- • RMSLineVoltageCompensation plier/squarer/divider circuit, voltage and current loop error amplifiers, and a precision voltage reference to implement average current mode control • PrecisionMultiplier/Squarer/Divider withRMSlinevoltagecompensation.Thiscontroltechniquemaintainscon- • Internal75kHzSynchronizable stant loop gain with changes in input voltage, which minimizes input line Oscillator currentdistortionovertheworldwideinputvoltagerange. • AverageCurrentModePWM The internal 75kHz oscillator includes an external clock input, allowing syn- Control chronization to downstream converters.Additionally, the device features an overvoltage protection comparator, a clamped MOSFET gate driver which • OvervoltageProtectionComparator self-biases low during undervoltage lockout, and low startup and supply • HighCurrent,ClampedGateDriver current. These devices are available in 8-pin plastic and ceramic dual in-line (DIP) packages, and 8-lead small outline (SOIC) packages. The UC1853 is specified for operation from –55°C to +125°C, the UC2853 is specified for operation from –25°C to +85°C, and the UC3853 is specified for operation from0°Cto+70°C. BLOCK DIAGRAM UDG-94120-1 11/97

UC1853 UC2853 UC3853 ABSOLUTE MAXIMUM RATINGS CONNECTION DIAGRAM SupplyVoltage(VCC).............................40V DIL-8,SOIC-8(TopView) OutputDriveCurrent, Continuous ................................0.125A JorN,DPackage Peak .......................................0.5A OutputMinimum Voltage.........................–0.3V IACMaximumInputCurrent........................1mA IMOMaximumOutputCurrent.....................–2mA IMOMinimumVoltage ...........................–0.3V FBMaximumInputVoltage..........................5V VCOMPMaximumVoltage.........................6.2V ICOMPSourcingCurrent....................Self-Limiting ICOMPSinkingCurrent ..........................20mA ICOMPMaximumVoltage .........................7.2V StorageTemperature...................–65°Cto+150°C JunctionTemperature...................–55°Cto+150°C LeadTemperature(Soldering,10sec.).............+300°C AllvoltageswithrespecttoGND.Currentsarepositiveinto, negativeoutofthespecifiedterminal.ConsultPackagingSection ofDatabookforthermallimitationsandconsiderationsof packages. ELECTRICAL CHARACTERISTICS Unlessotherwisestated,theseparametersapplyforTA=–55°Cto+125°Cforthe UC1853;–25°Cto+85°Cforthe2853;and0°Cto+70°CfortheUC3853;VCC= 16V,VFB=3V,IAC=100mA,VVCOMP=3.75V,VICOMP=3V,TA=TJ. PARAMETER TESTCONDITIONS MIN TYP MAX UNITS UndervoltageLockoutSection VCCTurn-onThreshold VVCOMP,VICOMPOpen 11.5 13 V Hysteresis 1.5 1.8 2.1 V SupplyCurrentSection IVCCStartup VCC=8V,IAC=100m A;VVCOMP,VICOMPOpen 250 500 mA IVCC IAC=0m A,VICOMP=0V 10 15 mA VoltageLoopErrorAmplifierSection Transconductance IOUT=±20m A0-70C 300 450 575 m mho Temperature 135 640 m mho InputVoltage 0-70C 2.925 3 3.075 V Temperature 2.9 3.1 V AVOL VVCOMP=1V–4V 50 60 dB OutputSinkCurrent VFB=3.2V,VVCOMP=3.75V 20 50 m A OutputSourceCurrent VFB=2.8V,VVCOMP=3.75V –50 –20 m A OutputVoltageHigh 5.5 6 V OutputVoltageLow 0.6 0.9 V CurrentLoopErrorAmplifierSection OffsetVoltage 0 6 mV VoltageGain VICOMP=1V–4V 70 dB SinkCurrent VIMO=100mV,VICOMP=3V 1 mA SourceCurrent VIMO=–0.1V,VICOMP=3V –150 –80 mA OutputHigh IICOMP=–50mA 6 6.8 V OutputLow IICOMP=50mA 0.3 0.8 V PWMModulatorGain VICOMP=2V–3V(Note1) 20 %/V 2

UC1853 UC2853 UC3853 ELECTRICAL CHARACTERISTICS Unlessotherwisestated,theseparametersapplyforTA=–55°Cto+125°Cforthe UC1853;–25°Cto+85°Cforthe2853;and0°Cto+70°CfortheUC3853;VCC= (continued) 16V,VFB=3V,IAC=100mA,VVCOMP=3.75V,VICOMP=3V,TA=TJ. PARAMETER TESTCONDITIONS MIN TYP MAX UNITS MultiplierSection OutputCurrent–IACLimited VCC=11V,VVCOMP=6V –230 –200 –170 m A OutputCurrent–Zero IAC=0m A –2 –0.2 2 m A OutputCurrent–PowerLimited VCC=12V,VVCOMP=5.5V –236 –178 –168 m A OutputCurrent VCC=12V,VVCOMP=2V –22 m A VCC=12V,VVCOMP=5V –156 m A VCC=40V,VVCOMP=2V –2 m A VCC=40V,VVCOMP=5V –14 m A MultiplierGainConstant VCC=12V,VVCOMP=5.5V(Note2) –1.05 –0.9 –0.75 V–1 OscillatorSection OscillatorInitialFrequency TA=25°C 67.5 75 82.5 kHz OscillatorFrequency Line,Load,Temperature 56 75 94 kHz SynchronizationFrequencyRange 100 kHz SynchronizationPulseAmplitude Pulseslewrate=100V/msec(Note3) 2 V OutputDriverSection MaximumOutputVoltage 0mAload,VCC=20V 12 15 17.5 V OutputHigh 0mAload,VCC=12V,ref.toVCC –2.7 –1.7 V –50mAload,VCC=12V,ref.toVCC –3 –2.2 V OutputLow(DeviceInactive) Vcc=0V,20mAload(Sinking) 0.9 2.0 V OutputLow(DeviceActive) 50mAload(Sinking) 0.5 1 V OUTRiseTime 1nFfromOUTtoGND 55 100 ns OUTFallTime 1nFfromOUTtoGND 35 100 ns OUTMaximumDutyCycle VICOMP=0V 88 93 % OVPComparatorSection ThresholdVoltage VoltsAboveEAInputV 90 150 mV Hysteresis 80 mV Note1: D DutyCycle PWMmodulatorgain= D VICOMP Note2: IAC•(VCOMP(cid:150)1.5V) Gainconstant(K)= VCC IMO•VCC• ,VCC=12V. 64 Note3. Synchronizationisaccomplishedwithafallingedgeof2Vmag- nitudeand100V/m secslewrate. 3

UC1853 UC2853 UC3853 PIN DESCRIPTIONS FB: Voltage Amplifier Inverting Input, Overvoltage vents excessive MOSFET gate-to-source voltage so that Comparator Input, Sync Input. This pin serves three the UC3853 can be operated with VCC and high as 40V. functions. FB accepts a fraction of the power factor A series gate resistor of at least 5 ohms should be used corrected output voltage through a voltage divider, and is to minimize clamp voltage overshoot. In addition, a nominally regulated to 3V. FB voltages 5% greater than Schottky diode such as a 1N5818 connected between nominal will trip the overvoltage comparator, and shut OUT and GND may be necessary to prevent parasitic down the output stage until the output voltage drops 5%. substratediodeconduction. TheinternaloscillatorcanbesynchronizedthroughFBby ICOMP: Current Loop Error Amplifier Output. The cur- injecting a 2V clock signal though a capacitor.To prevent rent loop error amplifier is a conventional operational false tripping of the overvoltage comparator, the clock amplifier with a 150m A current source class A output signal must have a fast falling edge, but a slow rising stage. Compensate the current loop by placing an im- edge.SeeApplicationNoteU-159formoreinformation. pedance between ICOMP and IMO. This output can GND: Ground. All voltages are measured with respect to swing above the oscillator peak voltage, allowing zero GND.The VCC bypass capacitor should be connected to dutycyclewhennecessary. groundasclosetotheGNDpinaspossible. VCC: Input Supply Voltage. This pin serves two func- IAC: AC Waveform Input. This input provides voltage tions.It supplies power to the chip, and an input voltage waveform information to the multiplier. The current loop level signal to the squarer circuit.When this input is con- will try to produce a current waveform with the same nectedtoaDCvoltageproportionaltotheACinputRMS shape as the IAC signal. IAC is a low impedance input, voltage,thevoltageloopgainisreducedby nominally at 2V, which accepts a current proportional to the input voltage.Connect a resistor from the rectified in- . 2 CC putlinetoIACwhichwillconduct500mAatmaximumline voltage. This configuration maintains constant loop gain. The UC3853 input voltage range extends from 12V to 40V, IMO:Multiplier Output and Current Sense Inverting Input. allowing an AC supply voltage range in excess of 85VAC The output of the multiplier and the inverting input of the to 265VAC. Bypass VCC with at least a 0.1m F ceramic current amplifier are connected together at IMO. Avoid capacitor to ensure proper operation. See the Applica- bringingthisinputbelow–0.5Vtopreventtheinternalpro- tionssectionfortherecommendedcircuitconfiguration. tection diode from conducting. The multiplier output is a current, making this a summing node and allowing a dif- VCOMP: Voltage Loop Error Amplifier Output. The ferential current error amplifier configuration to reject voltage loop error amplifier is a transconductance type ground noise.The input resistance at this node should be operational amplifier. A feedback impedance between 3.9k to minimize input bias current induced offset voltage. VCOMP and FB for loop compensation must be avoided See the Applications section for the recommended circuit to maintain proper operation of the overvoltage configuration. protection comparator. Instead, compensate the voltage loop with an impedance between VCOMP and GND. OUT:GateDriverOutput.OUTprovideshighcurrentgate When VCOMP is below 1.5V, the multiplier output drive for the external power MOSFET. A 15V clamp pre- currentiszero. 4

UC1853 UC2853 UC3853 UC3853 TYPICAL APPLICATION UDG-97127 Note:theapplicationcircuitshownisa100W,75KHzdesign. AdditionalapplicationinformationcanbefoundinApplication NoteU–159andDesignNoteDN–78. UNITRODECORPORATION 7CONTINENTALBLVD.•MERRIMACK,NH 03054 TEL.(603)424-2410•FAX(603)424-3460 5

PACKAGE OPTION ADDENDUM www.ti.com 18-Sep-2008 PACKAGING INFORMATION OrderableDevice Status(1) Package Package Pins Package EcoPlan(2) Lead/BallFinish MSLPeakTemp(3) Type Drawing Qty UC2853D ACTIVE SOIC D 8 75 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC2853DG4 ACTIVE SOIC D 8 75 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC2853DTR ACTIVE SOIC D 8 2500 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC2853DTRG4 ACTIVE SOIC D 8 2500 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC2853N ACTIVE PDIP P 8 50 Green(RoHS& CUNIPDAU N/AforPkgType noSb/Br) UC2853NG4 ACTIVE PDIP P 8 50 Green(RoHS& CUNIPDAU N/AforPkgType noSb/Br) UC3853D ACTIVE SOIC D 8 75 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC3853DG4 ACTIVE SOIC D 8 75 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC3853DTR ACTIVE SOIC D 8 2500 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC3853DTRG4 ACTIVE SOIC D 8 2500 Green(RoHS& CUNIPDAU Level-2-260C-1YEAR noSb/Br) UC3853N ACTIVE PDIP P 8 50 Green(RoHS& CUNIPDAU N/AforPkgType noSb/Br) UC3853NG4 ACTIVE PDIP P 8 50 Green(RoHS& CUNIPDAU N/AforPkgType noSb/Br) (1)Themarketingstatusvaluesaredefinedasfollows: ACTIVE:Productdevicerecommendedfornewdesigns. LIFEBUY:TIhasannouncedthatthedevicewillbediscontinued,andalifetime-buyperiodisineffect. NRND:Notrecommendedfornewdesigns.Deviceisinproductiontosupportexistingcustomers,butTIdoesnotrecommendusingthispartin anewdesign. PREVIEW:Devicehasbeenannouncedbutisnotinproduction.Samplesmayormaynotbeavailable. OBSOLETE:TIhasdiscontinuedtheproductionofthedevice. (2)EcoPlan-Theplannedeco-friendlyclassification:Pb-Free(RoHS),Pb-Free(RoHSExempt),orGreen(RoHS&noSb/Br)-pleasecheck http://www.ti.com/productcontentforthelatestavailabilityinformationandadditionalproductcontentdetails. TBD:ThePb-Free/Greenconversionplanhasnotbeendefined. Pb-Free(RoHS):TI'sterms"Lead-Free"or"Pb-Free"meansemiconductorproductsthatarecompatiblewiththecurrentRoHSrequirements forall6substances,includingtherequirementthatleadnotexceed0.1%byweightinhomogeneousmaterials.Wheredesignedtobesoldered athightemperatures,TIPb-Freeproductsaresuitableforuseinspecifiedlead-freeprocesses. Pb-Free(RoHSExempt):ThiscomponenthasaRoHSexemptionforeither1)lead-basedflip-chipsolderbumpsusedbetweenthedieand package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible)asdefinedabove. Green(RoHS&noSb/Br):TIdefines"Green"tomeanPb-Free(RoHScompatible),andfreeofBromine(Br)andAntimony(Sb)basedflame retardants(BrorSbdonotexceed0.1%byweightinhomogeneousmaterial) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. 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 incomingmaterialsandchemicals.TIandTIsuppliersconsidercertaininformationtobeproprietary,andthusCASnumbersandotherlimited informationmaynotbeavailableforrelease. Addendum-Page1

PACKAGE OPTION ADDENDUM www.ti.com 18-Sep-2008 InnoeventshallTI'sliabilityarisingoutofsuchinformationexceedthetotalpurchasepriceoftheTIpart(s)atissueinthisdocumentsoldbyTI toCustomeronanannualbasis. Addendum-Page2

PACKAGE MATERIALS INFORMATION www.ti.com 29-Jul-2008 TAPE AND REEL INFORMATION *Alldimensionsarenominal Device Package Package Pins SPQ Reel Reel A0(mm) B0(mm) K0(mm) P1 W Pin1 Type Drawing Diameter Width (mm) (mm) Quadrant (mm) W1(mm) UC2853DTR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1 UC3853DTR SOIC D 8 2500 330.0 12.4 6.4 5.2 2.1 8.0 12.0 Q1 PackMaterials-Page1

PACKAGE MATERIALS INFORMATION www.ti.com 29-Jul-2008 *Alldimensionsarenominal Device PackageType PackageDrawing Pins SPQ Length(mm) Width(mm) Height(mm) UC2853DTR SOIC D 8 2500 346.0 346.0 29.0 UC3853DTR SOIC D 8 2500 346.0 346.0 29.0 PackMaterials-Page2

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