LT1616注意事项Word格式.docx

LT1616注意事项Word格式.docx

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A

LowVCESATSwitch:

220mVat300mA

Tiny6-LeadSOT-23Package

WallTransformerRegulation

LocalLogicSupplyConversion:

12Vto5V

12Vor5Vto3.3V,2.5Vor1.8V

DistributedSupplyRegulation

DigitalCameras

Battery-PoweredEquipment

3.3VStep-DownConverter

VINBOOST

GNDFB

SHDNSW

5

VIN

4.5VTO25V

OFFON

4

6

C3

0.01µ

F

D1

D2

L1

10µ

H

23

R2

10k

R1

16.5k

C2

1616TA01

C1

VOUT

3.3V

300mA:

VIN=4.5VTO25V

400mA:

VIN=4.7VTO25V

C1:

TAIYO-YUDENTMK316BJ105

C2:

TAIYO-YUDENJMK316BJ106ML

D1:

ONSEMICONDUCTORMBR0530

D2:

1N4148

L1:

SUMIDACR43-100

Efficiency

LOADCURRENT（mA）

80

90

100

300400

1616G02

70

60

100200500

50

40

30

EFFICIENCY（%）

VIN=5V

VIN=20V

VIN=12V

FEATURESDESCRIPTIO

U

APPLICATIOS

TYPICALAPPLICATIO

2

（Note1）

InputVoltage（VIN）.................................................25V

BOOSTPinVoltage.................................................35V

BOOSTPinAboveSWPin......................................25V

SHDNPin...............................................................25V

FBVoltage................................................................6V

CurrentIntoFBPin...............................................±

1mA

OperatingTemperatureRange（Note2）..–40°

Cto85°

C

MaximumJunctionTemperature..........................125°

StorageTemperatureRange.................–65°

Cto150°

LeadTemperature（Soldering,10sec）..................300°

TJMAX=125°

C,θJA=250°

C/W

ORDERPART

NUMBER

S6PARTMARKING

LT1616ES6

LTNB

PARAMETERCONDITIONSMINTYPMAXUNITS

UndervoltageLockout3.353.6V

FeedbackVoltageG1.2251.251.275V

FBPinBiasCurrentVFB=MeasuredVREF+10mVG150600nA

QuiescentCurrentNotSwitching1.92.5mA

QuiescentCurrentinShutdownVSHDN=0V0.012µ

ReferenceLineRegulationVIN=5Vto25V0.005%/V

SwitchingFrequencyVFB=1.1VG11.41.8MHz

FrequencyShiftThresholdonFBPinfSW=700kHz0.44V

MaximumDutyCycleG8087%

SwitchCurrentLimit（Note3）630850mA

SwitchVCESATISW=300mA220350mV

SwitchLeakageCurrent10µ

MinimumBoostVoltageAboveSwitchISW=300mA1.62.5V

BOOSTPinCurrentISW=300mA712mA

SHDNInputVoltageHigh1.8V

SHDNInputVoltageLow0.4V

SHDNBiasCurrentVSHDN=3V815µ

VSHDN=0V0.010.1µ

TheGdenotesspecificationswhichapplyoverthefulloperatingtemperaturerange,otherwisespecificationsareatTA=25°

C.

VIN=10V,VBOOST=15V,unlessotherwisenoted.（Note2）

ABSOLUTEAXIURATIGS

WWWU

PACKAGE/ORDERIFORATIO

UUW

BOOST1

GND2

FB3

6SW

5VIN

4SHDN

TOPVIEW

S6PACKAGE

6-LEADPLASTICSOT-23

ELECTRICALCHARACTERISTICS

Note1:

AbsoluteMaximumRatingsarethosevaluesbeyondwhichthelife

ofthedevicemaybeimpaired.

Note2:

TheLT1616Eisguaranteedtomeetperformancespecifications

from0°

Cto70°

C.Specificationsoverthe–40°

Coperating

temperaturerangeareassuredbydesign,characterizationandcorrelation

withstatisticalprocesscontrols.

Note3:

Currentlimitguaranteedbydesignand/orcorrelationtostatictest.

Slopecompensationreducescurrentlimitathigherdutycycle.

Consultfactoryforpartsspecifiedwithwideroperatingtemperatureranges.

3

TYPICALPERFORACECHARACTERISTICS

UW

Efficiency,VOUT=5V

1616G01

VIN=8V

VIN=24V

SWITCHCURRENT（mA）

SWITCHVOLTAGE（mV）

200

300

400

500

200400

1616G03

600

Efficiency,VOUT=3.3VSwitchVoltageDrop

MaximumLoadCurrent

atVOUT=5VBOOSTPinCurrent

INPUTVOLTAGE（V）

20

1616G04

5101525

L=15µ

L=6.8µ

L=10µ

OUTPUTLIMITED

BYDISSIPATION

atVOUT=3.3V

1616G05

L=4.7µ

BOOSTPINCURRENT（mA）

8

10

1616G06

12

14

16

SwitchCurrentLimit

DUTYCYCLE（%）

SWITCHCURRENTLIMIT（mA）

TYPICAL

800

1000

1616G07

204060100

MINIMUM

FeedbackPinVoltage

TEMPERATURE（°

C）

–50

1.22

FEEDBACKPINVOLTAGE（V）

1.23

1.24

1.25

1.26

1.27

–2502550

1616G08

75100

UndervoltageLockout

3.1

UNDERVOLTAGELOCKOUT（V）

3.2

3.3

3.4

3.5

3.7

1616G11

3.6

OscillatorFrequency

SWITCHINGFREQUENCY（MHz）

0.75

1.00

2575

1616G09

0.50

0.25

–25050

1.50

1.75

2.00

SHDNPinCurrent

SHDNPINVOLTAGE

SHDNPINCURRENT（µ

120

5101520

1616G10

25

UUU

PIFUCTIOS

BOOST（Pin1）:

TheBOOSTpinisusedtoprovideadrive

voltage,higherthantheinputvoltage,totheinternal

bipolarNPNpowerswitch.

GND（Pin2）:

TietheGNDpintoalocalgroundplanebelow

theLT1616andthecircuitcomponents.Returnthefeed-

backdividertothispin.

FB（Pin3）:

TheLT1616regulatesitsfeedbackpinto1.25V.

Connectthefeedbackresistordividertaptothispin.Set

theoutputvoltageaccordingtoVOUT=1.25V（1+R1/R2）.

AgoodvalueforR2is10k.

Iftheinternal 

amplifier 

damageVOUT=0.81V（1+R1/R2）.

Notethatthis 

module 

iseasytobedamaged 

wheninuse,

SHDN（Pin4）:

TheSHDNpinisusedtoputtheLT1616in

shutdownmode.TietogroundtoshutdowntheLT1616.

Tieto2Vormorefornormaloperation.Iftheshutdown

featureisnotused,tiethispintotheVINpin.

VIN（Pin5）:

TheVINpinsuppliescurrenttotheLT1616’s

internalregulatorandtotheinternalpowerswitch.Thispin

mustbelocallybypassed.

SW（Pin6）:

TheSWpinistheoutputoftheinternalpower

switch.Connectthispintotheinductor,catchdiodeand

boostcapacitor.

BLOCKDIAGRA

W

Σ

R

DRIVERQ1

S

OSC

SLOPE

COMP

FREQUENCY

FOLDBACK

INTREG

AND

UVLO

VC

gm

1.25V

FB

1616BD

GND

Q

1BOOST

OPERATIOU

TheLT1616isaconstantfrequency,currentmodeBuck

regulator.The1.4MHzoscillatorenablesanRSflip-flop,

turningontheinternal600mApowerswitchQ1.Anampli-

fierandcomparatormonitorthecurrentflowingbetween

theVINandSWpins,turningtheswitchoffwhenthiscurrent

reachesaleveldeterminedbythevoltageatVC.Anerror

amplifiermeasurestheoutputvoltagethroughanexternal

resistordividertiedtotheFBpin.Thisamplifierservosthe

switchcurrenttoregulatetheFBpinvoltageto1.25V.An

activeclampontheVCnodeprovidescurrentlimit.

Aninternalregulatorprovidespowertothecontrolcir-

cuitry.Thisregulatorincludesanundervoltagelockoutto

preventswitchingwhenVINislessthan~3.5V.The

（RefertoBlockDiagram）

SHDNpinisusedtoplacetheLT1616inshutdown,

disconnectingtheoutputandreducingtheinputcurrent

tolessthan1µ

A.

Theswitchdriveroperatesfromeithertheinputorfrom

theBOOSTpin.Anexternalcapacitoranddiodeareused

togenerateavoltageattheBOOSTpinthatishigherthan

theinputsupply.Thisallowsthedrivertofullysaturatethe

internalbipolarNPNpowerswitchforefficientoperation.

TheoscillatorreducestheLT1616’soperatingfrequency

whenthevoltageattheFBpinislow.Thisfrequency

foldbackhelpstocontroltheoutputcurrentduringstart-

upandoverload.

APPLICATIOSIFORATIO

WUUU

TheLT1616efficientlyconvertspowerfromaninputvolt-

agesourcetoaloweroutputvoltageusinganinductorfor

energystorage.TheLT1616usesitsinternalpowerswitch

andanexternalcatchdiode（D1oftheapplicationcircuit

onthefirstpageofthisdatasheet）toproduceapulse-

widthmodulatedsquarewave.InductorL1andoutput

capacitorC2filterthissquarewavetoproduceaDCoutput

voltage.Anerroramplifierregulatestheoutputbycom-

paringtheoutput（dividedbythefeedbackresistorstring

R1andR2）toaninternalreference.TheLT1616uses

currentmodecontrol;

insteadofdirectlymodulatingthe

pulsewidth,theerroramplifiercontrolsthepeakcurrent

intheswitchandinductor.Currentmodecontro