KC1510说明书Word格式文档下载.docx

KC1510说明书Word格式文档下载.docx

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●0.8VReferenceVoltage

●1uALowShutdownCurrent

●3mALowSupplyCurrent

●100%DutyCycle

●Built-inLowRds（on）PowerMOSFET

●NoExternalCompensationRequired

●SupportLowESROutputCeramicCapacitors

●AdjustableCurrentLimit

●ShortCircuitandThermalProtection

●SOP-8LPb-FreePackage

Applications

●BroadbandCommunicationDevice

●LCDTV/Monitor

●StorageDevice

●WirelessApplication

●PrinterandotherPeripheralEquipment

●ADSLModem

●PCMotherboard

MarkingInformation

12（DateCode）

Fordatecoderule,pleasecontactoursalesrepresentativedirectly

34（Internalcode）

TypicalApplication

●12Vto5V/3Awith10uFLowESRCeramicCapacitor

●5Vto1.8V/3Awith330uFElectrolyticCapacitor

EfficiencyCurve

QuickDesignTable

（1）

ForE/Capplication,Iload=3A,ΔIL=0.6A,continuouscurrentmodeoperation.

L1:

RecommendedInductorR2:

OutputVoltageDivider

R1:

OutputVoltageDividerR3:

CurrentLimitSettingResistor

Vin

Vout

5V

9V

12V

18V

1.2V

6.8uH

1.5KΩ

R2:

3KΩ

R3:

5.6KΩ

8.2uH

1.5V

1.3KΩ

10uH

1.8V

25KΩ

2KΩ

2.5KΩ

12uH

2.5V

4.7KΩ

2.2KΩ

15uH

2.7KΩ

3.3V

18uH

22uH

6.8KΩ

27uH

36uH

10.2KΩ

1KΩ

33uH

18.2KΩ

QuickDesignTable

（2）

OutputVoltageDivide

C1:

Feed-ForwardCapacitorR3:

Vout

470pF

8.2Uh

FunctionalBlockDiagram

PinConfigurations

PinNo.

Name

Description

1

FB

Thispinsensesthefeedbackvoltagetoregulatetheoutputvoltage.Connectthispintoavoltagedividertosettheoutputvoltage

2

EN

Thispinallowsanexternalcontrolsignaltoturn-on/offthisdevice.Floatthispinorforceitbelow0.8Vtoturn-offthisdevice,forceitabove2Vtoturn-onthisdevice.Ifthisfeatureisnotneeded,connectthispintoINdirectly

3

OCSET

AddanexternalresistorfromthispintoINtosetcurrentLimit

4

IN

Theinputpinofthestep-downConverter

AsuitablylargecapacitormustbeconnectedfromthispintogroundtobypassnoiseontheinputoftheIC

5,6

SW

Theoutputpinofthestep-downconverter

Thispinistheswitchingnodethatsuppliespowertotheoutput,connectaLCfilterfromthispintotheoutputloadandarectifierdiodetotheground

7,8

GND

Thegroundpinofthestep–downconverter

Connectthispinthecircuitground.

AbsoluteMaximumRatings

Parameter

Rating

InputVoltage

28V

SWpinVoltageRange

-0.5V~Vin+0.5V

FBpinVoltageRange

-0.3V~Vin

EnpinVoltageRange

-0.3V~Vin+0.3V

StorageTemperatureRange

-65℃~150℃

JunctionTemperature

150℃

LeadSolderingTemperature（10sec）

300℃

Thesearestressratingonlyandfunctionaloperationisnotimplied.Exposuretoabsolutemaximumratingsforprolongedtimeperiodsmayaffectdevicereliability.Allvoltagearewithrespecttoground.

RccommendedOperatingCondition

InputVoltageRange

3.6V~28V

AmbienttemperatureRange

-40℃~85℃

JunctionTemperatureRange

-40℃~125℃

Theseareconditionsunderwhichthedevicefunctionsbutthespecificationsmightnotbeguaranteed.Forguaranteedspecificationsandtestconditions,pleaseseetheElectricalspecifications.

PackageInformation

Package

Symbol

ThermalResistance

（JunctiontoCase）

SOP-8L

ΘJC

20℃/W

（JunctiontoAmbient）

ΘJA

60℃/W

ElectricalSpecifications

Vin=12V,Voutsetto5V,Ta=25℃,unlessotherwisenoted.

TestCondition

Min

Typ

Max

Units

VIN

3.6

25

V

VFB

FeedbackVoltage

Iload=0.1A

0.8

Isw

SwitchCurrent

3.5

A

η

Efficiency

Vin=12V,Vout=5V,Iload=3A

92

%

Vin=5V,Vout=3.3V,Iload=3A

88

Fosc

OscillationFrequency

300

340

380

KHZ

FSCP

Frequencyofshort

CircuitProtection

40

50

60

DC

DutyCycle

Vfb=0V

100

Vfb=1.5V

Rds（ON）

InternalMOSFETONResistance

Vin=5V,VFB=0V

80

mΩ

Vin=12V,VFB=0V

Is

SupplyCurrent

VFB=1.5V

10

mA

ISD

ShutdownCurrent

VEN=0V

5

uA

VEN

ENpininput

ThresholdVoltage

RegulatorOFF

1.3

RegulatorON

2.0

IEN

ENpinBiasCurrent

20

Ifb

FBpinBiasCurrent

Iload=0.2A

0.1

0.5

Iocset

OCSETPinBias

Current

70

90

110

ΔVLine

LineRegulation

Vin=3.6V~25V

ΔVLoad

LoadRegulation

Iload=0.2A~3A

0.2

TSD

OverTemperature

Shutdown

145

℃

THYS

ShutdownHysteresis

TypicalperformanceCharacteristics

Vin=12V,Voutsetto3.3V,Ta=25℃,unlessotherwisenoted.

TypicalperformanceCharacteristics（Contd.）

ApplicationInformation

PWMControl

TheKC1510consistsofDC/DCconvertersthatemployapulse-widthmodulation（PWM）system.

InconvertersoftheKC1510,thepulsewidthvariesinarangefrom0to100%,accordingtotheloadcurrent.Theripplevoltageproducedbytheswitchingcaneasilyberemovedthroughafilterbecausetheswitchingfrequencyremainsconstant.Therefore,theseconvertersprovidealow-ripplepoweroverbroadrangesofinputvoltageandloadcurrent.

OutputVoltageProgramming

KC1510developsaband-gapbetweenthefeedbackpinandgroundpin.Therefore,theoutputvoltagecanbeformedbyR1andR2.Use1%metalfilmresistorsforthelowesttemperaturecoefficientandthebeststability.Selectlowerresistorvaluetominimizenoisepickupinthesensitivefeedbackpin,orhigherresistorvaluetoimproveefficiency

Theoutputvoltageisgivenbythefollowingformula.

Vout=VFBx（1+R1/R2）whereVFB=0.8V

ShortCircuitProtection

Whentheoutputisshortedtoground,theprotectioncircuitwillbetriggeredandtheoscillationfrequencydowntoapproximately40KHZ.Theoscillationfrequencywillreturnto310KHZoncetheoutputvoltageorthefeedbackvoltagerisesabove0V.

CurrentLimitSetting

ThisdevicereservesOCSETpintosettheswitchingpeakcurrent.Ingeneral,thepeakcurrentmustbe1.5timesofthecontinuousoutputcurrent.Itcanbecalculatedasbelow:

ICL=（IOCSETxROCSET）/RDS（ON）

WhereICListhecurrentlimit,IOCSETistheOCSETbiascurrent（90uATyp.）,andRDS（ON）istheON-resistanceoftheinternalpowerMOSFET.

Delaystart-up

ThefollowingcircuitusestheENpintoprovideatimedelaybetweentheinputvoltageisappliedandtheoutputvoltagecomesup.Astheinstantoftheinputvoltagerises,thechargingofcapacitorCDELAYpullstheENpinlow,keepingthedeviceoff.OncethecapacitorvoltagerisesabovetheEnpinthresholdvoltage,thedevicewillstarttooperate.Thestart-updelaytimecanbecalculatedbythefollowingformula:

VINx（1–e-T/（RxC））>

VEN

WhereTisthestart-updelaytime,RisRDALAY,CisCDALAY,andthetypicalVENis1.3V.Thisfeatureisusefulinsituationswheretheinputpowersourceislimitedintheamountofcurrentitcandeliver.Itallowstheinputvoltagetorisetoahighervoltagebeforethedevicestartsopera