UCC3802

•100µA Typical Starting Supply Current•500µA Typical Operating SupplyCurrent

•Operation to 1MHz•Internal Soft Start•Internal Fault Soft Start

•Internal Leading-Edge Blanking of theCurrent Sense Signal•1 Amp Totem-Pole Output

•70ns Typical Response from

Current-Sense to Gate Drive Output•1.5% Tolerance Voltage Reference•SamePinoutas UC3842 andUC3842A

Part NumberUCCx800UCCx801UCCx802UCCx803UCCx804UCCx805

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

DESCRIPTION

TheUCC1800/1/2/3/4/5familyofhigh-speed,low-powerintegratedcir-cuitscontainallofthecontrolanddrivecomponentsrequiredforoff-lineandDC-to-DCfixedfrequencycurrent-modeswitchingpowersupplieswith minimal parts count.

ThesedeviceshavethesamepinconfigurationastheUC1842/3/4/5family,andalsooffertheaddedfeaturesofinternalfull-cyclesoftstartand internal leading-edge blanking of the current-sense input.

TheUCC1800/1/2/3/4/5familyoffersavarietyofpackageoptions,tem-peraturerangeoptions,choiceofmaximumdutycycle,andchoiceofcrit-icalvoltagelevels.LowerreferencepartssuchastheUCC1803andUCC1805fitbestintobatteryoperatedsystems,whilethehigherrefer-enceandthehigherUVLOhysteresisoftheUCC1802andUCC1804make these ideal choices for use in off-line power supplies.

TheUCC180xseriesisspecifiedforoperationfrom–55oCto+125oC,theUCC280xseriesisspecifiedforoperationfrom–40oCto+85oC,andthe UCC380x series is specified for operation from 0oC to +70oC.

Maximum Duty Cycle

100%50%100%100%50%50%Reference Voltage

5V5V5V4V5V4VTurn-On Threshold

7.2V9.4V12.5V4.1V12.5V4.1VTurn-Off Threshold

6.9V7.4V8.3V3.6V8.3V3.6V

BLOCK DIAGRAM

UDG92009-303/99

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

ABSOLUTE MAXIMUM RATINGS (Note 1)

VCCVoltage (Note 2). . . . . . . . . . . . . . . . . . . . . . . . . . . .12.0VVCCCurrent. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30.0mAOUT Current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .±1.0AOUT Energy (Capacitive Load). . . . . . . . . . . . . . . . . . .20.0µJAnalog Inputs (FB, CS). . . . . . . . . . . . . . . . . . . .–0.3V to 6.3VPower Dissipation at TA< +25°C (N or J Package). . . . .1.0WPower Dissipation at TA< +25°C (D Package). . . . . . . .0.65WStorage Temperature Range. . . . . . . . . . . . .–65°C to +150°CLead Temperature (Soldering, 10 Seconds). . . . . . . .+300°CNote 1:All voltages are with respect toGND.All currents arepositive into the specified terminal.ConsultUnitrodedatabookfor information regarding thermal specifica-tions and limitations of packages.Note 2:In normal operationVCCis powered through a currentlimiting resistor.Absolute maximum of 12V applieswhenVCCis driven from a low impedance source suchthat ICCdoes not exceed 30mA.CONNECTION DIAGRAMS

TSSOP-8(Top View)PWPackageREFVCCOUTGND1234COMPFBCSRC8765TEMPERATURE AND PACKAGE SELECTION

UCC1800UCC2800UCC3800

Temperature Range–55°C to +125°C–40°C to +85°C0°C to +70°C

Available Packages

JN, D,PWN, D,PW

DIL-8,SOIC-8(Top View)J or N,D Package

COMP

FBCS

1234

8765

REFVCCOUTGND

ORDERING INFORMATION

UCC

80PACKAGE

PRODUCTOPTIONTEMPERATURERANGE

RC

ELECTRICAL CHARACTERISTICSUnless otherwise stated, these specifications apply for –55°C≤TA≤+125°C for

UCC180x; –40°C≤TA≤+85°C for UCC280x; 0°C≤TA≤+70°C for UCC380x;VCC=10V (Note 3); RT=100k from REF to RC;CT=330pF from RC toGND; 0.1µF capacitor fromVCCtoGND; 0.1µF capacitor fromVREFtoGND. TA=TJ.

PARAMETER

TEST CONDITIONS

MIN

Reference SectionOutput VoltageLoad RegulationTotal VariationOutput Noise VoltageLong Term StabilityOutput Short CircuitOscillator SectionOscillator FrequencyTemperature StabilityAmplitude peak-to-peakOscillator Peak Voltage

UCCx800/1/2/4 (Note 4)UCCx803/5 (Note 4)(Note 9)

2.2026

46312.52.402.45

2.55

2.255236

4026

46312.52.402.45

2.555236

kHzkHz%VV

TJ=+25°C, I=0.2mA, UCCx800/1/2/4TJ=+25°C, I=0.2mA, UCCx803/50.2mAUCCx800/1/2/4 (Note 7)UCCx803/5 (Note 7)

10Hz≤f≤10kHz,TJ=+25°C (Note 9)TA=+125°C, 1000 Hours (Note 9)

–.883.90

4.9255.005.07.9255.003.94

4.00105.004.001305

–35

–5

4.06305.104.08

4.883.903.94

4.00105.004.001305

–355.07.06255.104.08

mVVV

µV

UCC180XUCC280XTYP

MAX

MIN

UCC380XTYP

MAX

UNITS

V

mVmA

2

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

ELECTRICAL CHARACTERISTICSUnless otherwise stated, these specifications apply for –55°C≤TA≤+125°C for

UCC180x; –40°C≤TA≤+85°C for UCC280x; 0°C≤TA≤+70°C for UCC380x;VCC=10V (Note 3); RT=100k from REF to RC;CT=330pF from RC toGND; 0.1µF capacitor fromVCCtoGND; 0.1µF capacitor fromVREFtoGND. TA=TJ.

PARAMETER

Error Amplifier SectionInput VoltageInput Bias CurrentOpen Loop Voltage GainCOMPSink CurrentCOMPSource CurrentGain Bandwidth ProductPWMSection

Maximum Duty CycleMinimum Duty CycleCurrent Sense SectionGain

Maximum Input SignalInput Bias CurrentCS Blank TimeOver-Current ThresholdCOMPto CS OffsetOutput SectionOUT Low Level

I=20mA, all partsI=200mA, all parts

I=50mA,VCC=5V, UCCx803/5I=20mA,VCC=0V, all parts

OUT HighVSAT(VCC-OUT)Rise TimeFall Time

UndervoltageLockout SectionStart Threshold (Note 8)

UCCx800UCCx801UCCx802/4UCCx803/5

Stop Threshold (Note 8)

UCCx1800UCCx1801UCCx802/4UCCx803/5

Start to StopHysteresis

UCCx800UCCx801UCCx802/4UCCx803/5

6.68.611.53.76.36.87.63.20.121.63.50.2

7.29.412..16.97.48.33.60.324.20.5

7.810.213..57.58.09.04.00.482.45.10.8

6.68.611.53.76.36.87.63.20.121.63.50.2

7.29.412..16.97.48.33.60.324.20.5

7.810.213..57.58.09.04.00.482.45.10.8

VVVVVVVVVVVV

I=–20mA, all partsI=–200mA, all parts

I=–50mA,VCC=5V, UCCx803/5CL=1nFCL=1nF

0.10.350.150.70.151.00.44144

0.40.900.401.20.401.90.97075

0.10.350.150.70.151.00.44144

0.40.900.401.20.401.90.97075

VVVVVVVnsns

CS=0V(Note 5)

COMP=5V (Note 6)

1.100.9

1.651.01001.550.90

1.801.12001501.681.35

1.100.9

1.651.01001.550.90

1.801.12001501.681.35

V/VVnAnsVV

UCCx800/2/3UCCx801/4/5COMP=0V

9748

9949

100500

9748

9949

100500

%%

FB=2.7V,COMP=1.1VFB=1.8V,COMP=REF–1.2V(Note 9)

COMP=2.5V; UCCx800/1/2/4COMP=2.0V; UCCx803/5

2.441.95

2.502.080

3.5

–0.52

–0.82.562.051

2.441.95

2.502.080

2.5

–0.52

–0.82.562.051

µA

TEST CONDITIONS

UCC180XUCC280X

UCC380XUNITS

V

–1

600.3–0.2

–1

600.4–0.2

dBmAmAMHz

–200

501.420.45

–200

501.420.45

3

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

ELECTRICAL CHARACTERISTICSUnless otherwise stated, these specifications apply for –55°C≤TA≤+125°C for

UCC180x; –40°C≤TA≤+85°C for UCC280x; 0°C≤TA≤+70°C for UCC380x;VCC=10V (Note 3); RT=100k from REF to RC;CT=330pF from RC toGND; 0.1µF capacitor fromVCCtoGND; 0.1µF capacitor fromVREFtoGND. TA=TJ.

PARAMETER

Soft Start SectionCOMPRise TimeOverall SectionStart-up Current

Operating Supply CurrentVCCInternalZenerVoltage

VCC< Start ThresholdFB=0V, CS=0VICC=10mA (Note 8)

120.5

0.10.513.51.0

0.21.015

120.5

0.10.513.51.0

0.21.015

mAmAVV

FB=1.8V, Rise from 0.5V to REF–1V

4

10

4

10

ms

TEST CONDITIONS

UCC180XUCC280X

UCC380X

UNITS

VCCInternalZenerVoltage MinusUCCx802/4Start Threshold Voltage

Note 3: AdjustVCCabove the start threshold before setting at 10V.Note 4: Oscillator frequency for the UCCx800, UCCx802 and UCCx803 is the output frequency.Oscillator frequency for the UCCx801, UCCx804 and UCCx805 is twice the output frequency.∆VCOMPNote 5: Gain is defined by:A=0≤VCS≤0.8V.∆VCSNote 6: Parameter measured at trip point of latch with Pin 2 at 0V.Note 7: Total Variation includes temperature stability and load regulation.Note 8: Start Threshold, Stop Threshold andZenerShunt Thresholds track one another.Note 9: Guaranteed by design. Not 100% tested in production.PIN DESCRIPTIONS

COMP:COMPistheoutputoftheerroramplifierandtheinput of thePWMcomparator.

Unlikeotherdevices,theerroramplifierintheUCC3800familyisatrue,lowoutput-impedance,2MHzoperationalamplifier.Assuch,theCOMPterminalcanbothsourceandsinkcurrent.However,theerroramplifierisinternallycurrentlimited,sothatyoucancommandzerodutycycleby externally forcingCOMPtoGND.

TheUCC3800familyfeaturesbuilt-infullcycleSoftStart.SoftStartisimplementedasaclamponthemaximumCOMPvoltage.

CS:CSistheinputtothecurrentsensecomparators.TheUCC3800familyhastwodifferentcurrentsensecomparators:thePWMcomparatorandanover-currentcomparator.

TheUCC3800familycontainsdigitalcurrentsensefilter-ing,whichdisconnectstheCSterminalfromthecurrentsensecomparatorduringthe100nsintervalimmediatelyfollowingtherisingedgeoftheOUTpin.Thisdigitalfilter-ing,alsocalledleading-edgeblanking,meansthatinmostapplications,noanalogfiltering(RCfilter)isre-quiredonCS.ComparedtoanexternalRCfiltertech-nique,theleading-edgeblankingprovidesasmaller

4

effectiveCStoOUTpropagationdelay.Note,however,thattheminimumnon-zeroOn-TimeoftheOUTsignalisdirectlyaffectedbytheleading-edge-blankingandtheCS to OUT propagation delay.

Theover-currentcomparatorisonlyintendedforfaultsensing,andexceedingtheover-currentthresholdwillcause a soft start cycle.

FB:FBistheinvertinginputoftheerroramplifier.Forbeststability,keepFBleadlengthasshortaspossibleand FB stray capacitance as small as possible.

GND:GNDisreferencegroundandpowergroundforallfunctions on this part.

OUT:OUTistheoutputofahigh-currentpowerdrivercapableofdrivingthegateofapowerMOSFETwithpeakcurrentsexceeding±750mA.OUTisactivelyheldlow whenVCCis below theUVLOthreshold.

Thehigh-currentpowerdriverconsistsofFEToutputde-vices,whichcanswitchallofthewaytoGNDandallofthewaytoVCC.Theoutputstagealsoprovidesaverylowimpedancetoovershootandundershoot.Thismeansthatinmanycases,externalschottkyclampdiodesarenot required.

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

PIN DESCRIPTIONS (cont.)

RC:RCistheoscillatortimingpin.Forfixedfrequencyoperation,settimingcapacitorchargingcurrentbycon-nectingaresistorfromREFtoRC.Setfrequencybycon-nectingatimingcapacitorfromRCtoGND.Forbestperformance,keepthetimingcapacitorleadtoGNDasshortanddirectaspossible.Ifpossible,useseparategroundtracesforthetimingcapacitorandallotherfunc-tions.

Thefrequencyofoscillationcanbeestimatedwiththefollowing equations:

UCCx800/1/2/4:F=

1.5R•Cusedasthelogicpowersupplyforhighspeedswitchinglogic on the IC.

WhenVCCisgreaterthan1VandlessthantheUVLOthreshold,REFispulledtogroundthrougha5kohmre-sistor.ThismeansthatREFcanbeusedasalogicout-putindicatingpowersystemstatus.ItisimportantforreferencestabilitythatREFisbypassedtoGNDwithaceramiccapacitorasclosetothepinaspossible.Anelectrolyticcapacitormayalsobeusedinadditiontotheceramiccapacitor.Aminimumof0.1µFceramicisre-quired.AdditionalREFbypassingisrequiredforexternalloads greater than 2.5mA on the reference.

Topreventnoiseproblemswithhighspeedswitchingtransients,bypassREFtogroundwithaceramiccapaci-tor very close to the IC package.

VCC:VCCisthepowerinputconnectionforthisdevice.InnormaloperationVCCispoweredthroughacurrentlimitingresistor.AlthoughquiescentVCCcurrentisverylow,totalsupplycurrentwillbehigher,dependingonOUTcurrent.TotalVCCcurrentisthesumofquiescentVCCcurrentandtheaverageOUTcurrent.KnowingtheoperatingfrequencyandtheMOSFETgatecharge(Qg),average OUT current can be calculated from:

10.

UCCx803, UCCx805:F=

R•CwherefrequencyisinHz,resistanceisinohms,andca-pacitanceisinfarads.Therecommendedrangeoftimingresistorsisbetween10kand200kandtimingcapacitoris100pFto1000pF.Neveruseatimingresistorlessthan10k.

Topreventnoiseproblems,bypassVCCtoGNDwithaceramiccapacitorasclosetotheVCCpinaspossible.Anelectrolyticcapacitormayalsobeusedinadditiontothe ceramic capacitor.

REF:REFisthevoltagereferencefortheerroramplifierandalsoformanyotherfunctionsontheIC.REFisalso

IOUT=Qg×F.

The UCC3800/1/2/3/4/5 oscillator generates a sawtoothwaveform on RC.The rise time is set by the time constant ofRTand CT.The fall time is set by CT and an internal transis-tor on-resistance of approximately 125Ω.During the falltime, the output is off and the maximum duty cycle is re-duced below 50% or 100% depending on the part number.Larger timing capacitors increase the discharge time and re-duce the maximum duty cycle and frequency.Figure 1.Oscillator.Figure 2.Error amplifier gain/phase response.5

UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

4.003.983.963.94VREF(V)1000Oscillator Freq.(kHz)3.923.903.883.863.843.8244.24.44..85.2VCC(V)55.45.65.86101000pF0p33F0pF1n20F1010100RT(k)1000Figure 3.UCC1803/5VREFvs.VCC;ILOAD= 0.5mA.1000Figure 4.UCC1800/1/2/4 oscillator frequency vs.RTand CT.10099.5Oscillator Freq.(kHz)Maximum Duty Cycle (%)9998.5CTCT98CT= 100= 2100100pF200pF330pF1nFpF97.59796.59695.59500pF= 330pF1010100RT(k)100010100Oscillator Frequency(kHz)1000Figure 5.UCC1803/5 oscillator frequency vs.RTandCT.5049.5Figure 6.UCC1800/2/3 maximum duty cycle vs.oscillator frequency.1614121V, 01 nFMaximum Duty Cycle (%)49CTCT= 1ICC(mA)48.847.746.510108200VCC= C VCF, 1nV8 = = 230pF00100Oscillator Frequency(kHz)Figure 7.UCC1801/4/5 maximum duty cycle vs.oscillator frequency.6

CT= 3pF00pF = C VCo Lo10V, NadVCC= 8V, No Load10001002003004005006007008009001000Oscillator Frequency(kHz)Figure 8.UCC1800 ICCvs.oscillator frequency.UCC1800/1/2/3/4/5UCC2800/1/2/3/4/5UCC3800/1/2/3/4/5

8765CVC500450= 1n, 10VFUCC1803/00Dead Time (ns)3503002502001501005001002003004005006007008009001000UCC1800/1/2/4ICC(mA)432100 =C VCnF, 1 8VNo L 10V, = C CVoad, No LVCC= 8Voad1002003004005006007008009001000Oscillator Frequency(kHz)CT(pF)Figure 8.UCC1805 ICCvs.oscillator frequency.1.11.00.90.80.70.60-55-50Figure 9.Dead time vs.CT,RT= 100k.COMP to CS Offset (Volts)Slope = 1.8mV/°C-250255075100125Temperature (°C)Figure 10.COMPto CS offset vs.temperature,CS = 0V.7

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