參數(shù)資料
型號(hào)： LTC3541EDD-3#TR
廠商： LINEAR TECHNOLOGY CORP
元件分類： 穩(wěn)壓器
英文描述： 1.25 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO10
封裝： 3 X 3 MM, PLASTIC, M0-229WEED-2, DFN-10
文件頁(yè)數(shù)： 7/20頁(yè)
文件大?。?/td> 379K
代理商： LTC3541EDD-3#TR
LTC3541-3
35413fc
APPLICATIO S I FOR ATIO
W
U
equaltologichigh),efficiencyistypicallydominatedby
thelossacrossthelinearregulatoroutputdeviceandVIN
quiescentcurrent.Inatypicalefficiencyplot,theefficiency
curveatverylowloadcurrentscanbemisleadingsince
theactualpowerlostisoflittleconsequence.
1.TheVINquiescentcurrentlossinthebuckisduetotwo
components:theDCbiascurrentasgivenintheElectrical
Characteristicsandtheinternalmainswitchandsynchro-
nousswitchgatechargecurrents.Thegatechargecurrent
resultsfromswitchingthegatecapacitanceoftheinternal
powerswitches.Eachtimethegateisswitchedfromhigh
tolowtohighagain,apacketofcharge,dQ,movesfrom
VINtoground.TheresultingdQ/dtisthecurrentoutof
VINthatistypicallylargerthantheDCbiascurrentand
proportionaltofrequency.BoththeDCbiasandgatecharge
lossesareproportionaltoVINandthustheireffectswill
bemorepronouncedathighersupplyvoltages.
2.I2Rlossesarecalculatedfromtheresistancesofthe
internalswitches,RSW,andexternalinductorRL.Incon-
tinuousmode,theaverageoutputcurrentflowingthrough
inductorLis“chopped”betweenthemainswitchandthe
synchronousswitch.Thus,theseriesresistancelooking
into the SW pin is a function of both top and bottom
MOSFETRDS(ON)andthedutycycle(DC)asfollows:
RSW=(RDS(ON)TOP)(DC)+(RDS(ON)BOT)(1–DC)
TheRDS(ON)forboththetopandbottomMOSFETscan
beobtainedfromtheTypicalPerformanceCharacteristics
curves.Thus,toobtainI2Rlosses,simplyaddRSWto
RLandmultiplytheresultbythesquareoftheaverage
outputcurrent.
3.LossesintheVLDO/linearregulatorareduetotheDCbias
currentsasgivenintheElectricalCharacteristicsandtothe
(VIN–VOUT)voltagedropacrosstheinternaloutputdevice
transistor.
Other losses when the buck and VLDO regulator are
in operation (ENBUCK and ENVLDO equal logic high),
includingCINandCOUTESRdissipativelossesandinduc-
torcorelosses,generallyaccountforlessthan2%total
additionalloss.
THERMAL CONSIDERATIONS
The LTC3541-3 requires the package backplane metal
(GNDpin)tobewellsolderedtothePCboard.Thisgives
the DFN package exceptional thermal properties. The
power handling capability of the device will be limited
bythemaximumratedjunctiontemperatureof125°C.
TheLTC3541-3hasinternalthermallimitingdesignedto
protectthedeviceduringmomentaryoverloadconditions.
Forcontinuousnormalconditions,themaximumjunction
temperatureratingof125°Cmustnotbeexceeded.Itis
importanttogivecarefulconsiderationtoallsourcesof
thermalresistancefromjunctiontoambient.Additional
heatsourcesmountednearbymustalsobeconsidered.
Forsurfacemountdevices,heatsinkingisaccomplished
byusingtheheat-spreadingcapabilitiesofthePCboard
anditscoppertraces.Copperboardstiffenersandplated
throughholescanalsobeusedtospreadtheheatgener-
atedbypowerdevices.
ToavoidtheLTC3541-3exceedingthemaximumjunction
temperature,somethermalanalysisisrequired.Thegoal
ofthethermalanalysisistodeterminewhetherthepower
dissipatedexceedsthemaximumjunctiontemperatureof
thepart.Thetemperatureriseisgivenby:
TR=PDθJA
wherePDisthepowerdissipatedbytheregulatorandθJA
isthethermalresistancefromthejunctionofthedieto
theambienttemperature.
Thejunctiontemperature,TJ,isgivenby:
TJ=TA+TR
whereTAistheambienttemperature.
Asanexample,considertheLTC3541-3ataninputvolt-
ageVINof3V,anLVINvoltageof1.8Vprovidedbythebuck
regulator,anLVOUTvoltageof1.575V,aloadcurrentof
300mAfortheVLDOregulator,aloadcurrentof200mA
forthebuck(totalloadforbuck=500mA),andanambient
temperatureof85°C.Fromthetypicalperformancegraph
ofswitchresistance,theRDS(ON)oftheP-channelswitchat
相關(guān)PDF資料
PDF描述
LTC3542EDC 0.5 A SWITCHING REGULATOR, 2700 kHz SWITCHING FREQ-MAX, PDSO6
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LTC3543EDCB#PBF 1.3 A SWITCHING REGULATOR, 2250 kHz SWITCHING FREQ-MAX, PDSO6
LTC3543EDCB#TRM 1.3 A SWITCHING REGULATOR, 2250 kHz SWITCHING FREQ-MAX, PDSO6
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
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LTC3542-1 制造商:LINER 制造商全稱:Linear Technology 功能描述:500mA, 2.25MHz 2.8V Output Synchronous Step-Down DC/DC Converter
LTC3542EDC#PBF 制造商:Linear Technology 功能描述:DC-DC CONVERTER BUCK 2.25MHZ 制造商:Linear Technology 功能描述:DC-DC CONVERTER, BUCK, 2.25MHZ, 500mA, DFN-6; Primary Input Voltage:5.5V; No. of Outputs:1; Output Current:500mA; No. of Pins:6; Operating Temperature Min:-40C; Operating Temperature Max:85C; Package / Case:6-DFN ;RoHS Compliant: Yes
LTC3542EDC#TRMPBF 功能描述:IC REG BUCK SYNC ADJ 0.5A 6DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 產(chǎn)品培訓(xùn)模塊:High Efficiency Current Mode Switching Regulators CMOS LDO Regulators 特色產(chǎn)品:BD91x Series Step-Down Regulators 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:降壓（降壓） 輸出類型:兩者兼有 輸出數(shù):2 輸出電壓:3.3V，0.8 V ~ 2.5 V 輸入電壓:4.5 V ~ 5.5 V PWM 型:電流模式 頻率 - 開(kāi)關(guān):1MHz 電流 - 輸出:1.5A 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:20-VFQFN 裸露焊盤 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:VQFN020V4040 產(chǎn)品目錄頁(yè)面:1373 (CN2011-ZH PDF) 其它名稱:BD9152MUV-E2TR
LTC3542EDC#TRPBF 功能描述:IC REG BUCK SYNC ADJ 0.5A 6DFN RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開(kāi)關(guān)穩(wěn)壓器 系列:- 標(biāo)準(zhǔn)包裝:500 系列:- 類型:切換式電容器（充電泵），反相 輸出類型:固定 輸出數(shù):1 輸出電壓:-3V 輸入電壓:2.3 V ~ 5.5 V PWM 型:Burst Mode? 頻率 - 開(kāi)關(guān):900kHz 電流 - 輸出:100mA 同步整流器:無(wú) 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:SOT-23-6 細(xì)型，TSOT-23-6 包裝:帶卷 (TR) 供應(yīng)商設(shè)備封裝:TSOT-23-6 其它名稱:LTC1983ES6-3#TRMTR
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