说明综合合并

TheFutureofAnalogIC

1.2A,24V,Step-DownConverterinaTSOT23-TheMP2359isamonolithicstep-downswitchmodeconverterwithabuilt-inpowerMOSFET.Itachieves1.2Apeakoutputcurrentoverawideinputsupplyrangewithexcellentloadandlineregulation.Currentmodeoperationprovidesfasttransientresponseandeasesloopstabilization.Faultconditionprotectionincludescycle-by-cyclecurrentlimitingandthermalTheMP2359requiresaminimumnumberofreadilyavailablestandardexternalcomponents.TheMP2359isavailableinTSOT23-6andSOT23-6packages.EVALUATIONBOARDBoard2.1”Xx1.9”Yx

1.2APeakOutput0.35ΩInternalPowerMOSFETStablewithLowESROutputCeramicUpto92%0.1μAShutdownFixed1.4MHzThermalCycle-by-CycleOverCurrentWide4.5Vto24VOperatingInputOutputAdjustablefrom0.81Vto DistributedPowerBatteryPre-RegulatorforLinearWLEDForMPSgreenstatus,pleasevisitMPSwebsiteunderQualityAssurance.MonolithicPowerSystems,Inc.TYPICAL

EfficiencyvsLoadCurrents 5

VVN=VN=VOUT=

SW

EFFICIENCYEFFICIENCYV@ OFF 4

2

0

LOADCURRENTORDERINGPartTopFreeAirTemperature-40Cto+85-40Cto+85*ForTape&Reel,addsuffix–Z(eg.ForRoHScompliantpackaging,addsuffix–LF(eg.**ForTape&Reel,addsuffix–Z(eg.ForRoHScompliantpackaging,addsuffix–LF(eg.PACKAGETOP162534ABSOLUTEMAXIMUMRATINGS ThermalResistance SupplyVoltage VBSVSW+AllOther VtoContinuousPowerDissipation(TA=+25°C) JunctionTemperature150Lead 260StorageTemperature-65Cto+150RecommendedOperatingConditionsSupplyVoltageVIN Vto24VOutputVoltage VtoAmbientTemperature-40Cto+85CMaxinputcurrentintotheEN

110..SOT23-6220110..Exceedingtheseratingsmaydamagethe ThemaximumallowablepowerdissipationisafunctionofthemaximumjunctiontemperatureTJ(MAX),thejunction-to-ambientthermalresistanceθJA,andtheambienttemperatureTA.ThemaximumallowablecontinuouspowerdissipationatanyambienttemperatureiscalculatedbyPD(MAX)=(TJ(MAX)-TA)/θJA.Exceedingthemaximumallowablepowerdissipationwillcauseexcessivedietemperature,andtheregulatorwillgointothermalshutdown.Internalthermalshutdowncircuitryprotectsthedevicefrompermanentdamage. Thedevicefunctionisnotguaranteedoutsideoftherecommendedoperatingconditions.MeasuredonJESD51-7,4-layerVIN=12V,TA=+25C,unlessotherwiseFeedback4.5V£VIN£VFeedbackVFB=Switch-OnResistanceΩSwitchVEN=0V,VSW=CurrentLimitAOscillatorVFB=Fold-backVFB=MaximumDutyVFB=%MinimumOn-TimeUnderVoltageLockoutThresholdVUnderVoltageLockoutThresholdENInputLowVENInputHighVENInputVEN=VEN=SupplyCurrentVEN=SupplyCurrentVEN=2V,VFB=ThermalShutdownGuaranteedbyPINPin1Bootstrap.AcapacitorisconnectedbetweenSWandBSpinstoformafloatingsupplyacrossthepowerswitchdriver.Thiscapacitorisneededtodrivethepowerswitch’sgateabovethesupplyvoltage.2Ground.Thispinisthevoltagereferencefortheregulatedoutputvoltage.Forthisreasoncaremustbetakeninitslayout.ThisnodeshouldbeplacedoutsideoftheD1toC1groundpathtopreventswitchingcurrentspikesfrominducingvoltagenoiseintothepart.3Feedback.AnexternalresistordividerfromtheoutputtoGND,tappedtotheFBpinsetstheoutputvoltage.Topreventcurrentlimitrunawayduringashortcircuitfaultcondition,thefrequencyfoldbackcomparatorlowerstheoscillatorfrequencywhentheFBvoltageisbelow4On/OffControlInput.PullENabove1.2Vtoturnthedeviceon.Forautomaticenable,connecta100kΩresistorbetweenthispinandVinpin.5SupplyVoltage.TheMP2359operatesfroma+4.5Vto+24Vunregulatedinput.C1isneededtopreventlargevoltagespikesfromappearingattheinput.6SwitchVIN=12V,VOUT=3.3V,L=4.7µH,C1=10µF,C2=22µF,TA=+25ºC,unlessotherwiseEFFICIENCYEFFICIENCY0

EfficiencyvsLoad

EFFICIENCYEFFICIENCY0

EfficiencyvsLoad LOADCURRENT(

LOADCURRENTFEEDBACKFEEDBACKVOLTAGE

FeedbackVoltagevsDieTemperature

SWITCHINGSWITCHINGFREQUENCY

SwitchingFrequencyvsDieTemperature-50-250255075100125 -50-250255075100125DIETEMPERATURE DIETEMPERATUREVIN=12V,VOUT=3.3V,L=4.7µH,C1=10µF,C2=22µF,TA=+25ºC,unlessotherwiseCURRENTCURRENTLIMIT0

CurrentLimitvsDutyCycle

SteadyStateIOUT= DUTYCYCLEShortCircuit ShortCircuit

Start-upthroughNo

Start-upthroughIOUT=1AResistive

Shut-downthroughNo

Shut-downthroughIOUT=1AResistive

TheMP2359isacurrentmodebuckregulator.Thatis,theEAoutputvoltageisproportionaltothepeakinductorcurrent.Atthebeginningofacycle,M1isoff.TheEAoutputvoltageishigherthanthecurrentsenseamplifieroutput,andthecurrentcomparator’soutputislow.Therisingedgeofthe1.4MHzCLKsignalsetstheRSFlip-Flop.ItsoutputturnsonM1thusconnectingtheSWpinandinductortotheinputsupply.TheincreasinginductorcurrentissensedandamplifiedbytheCurrentSenseAmplifier.RampcompensationissummedtotheCurrentSenseAmplifieroutputandcomparedtotheErrorAmplifieroutputbythePWMComparator.WhenthesumoftheCurrentSenseAmplifieroutputandtheSlopeCompensationsignalexceedstheEAoutputvoltage,theRSFlip-FlopisresetandM1isturnedoff.TheexternalSchottkyrectifierdiode(D1)conductstheinductorcurrent.

IfthesumoftheCurrentSenseAmplifieroutputandtheSlopeCompensationsignaldoesnotexceedtheEAoutputforawholecycle,thenthefallingedgeoftheCLKresetstheFlip-Flop.TheoutputoftheErrorAmplifierintegratesthevoltagedifferencebetweenthefeedbackandthe0.81Vbandgapreference.ThepolarityissuchthataFBpinvoltagelowerthan0.81VincreasestheEAoutputvoltage.SincetheEAoutputvoltageisproportionaltothepeakinductorcurrent,anincreaseinitsvoltagealsoincreasescurrentdeliveredtotheoutput.R

Figure1—FunctionalBlockSettingOutputTheexternalresistordividerisusedtosettheoutputvoltage(seetheschematiconfrontpage).Table1showsalistofresistorselectionforcommonoutputvoltages.ThefeedbackresistorR1alsosetsthefeedbackloopbandwidthwiththeinternalcompensationcapacitor(seeFigure1).R2canbedeterminedR2 VOUT-Table1—ResistorSelectionforCommonOutputVoltagesVOUTR1R280.664.949.923.749.916.2549.99.53SelectingtheA1µHto10µHinductorwithaDCcurrentratingofatleast25%percenthigherthanthemaximumloadcurrentisrecommendedformostapplications.Forhighestefficiency,theinductor’sDCresistanceshouldbelessthan200mΩ.RefertoTable2forsuggestedsurfacemountinductors.Formostdesigns,therequiredinductancevaluecanbederivedfromthefollowingequation.L=VOUT·(VIN-VOUT)VIN·DIL·fSWWhereΔIListheinductorrippleChoosetheinductorripplecurrenttobe30%ofthemaximumloadcurrent.Themaximuminductorpeakcurrentiscalculatedfrom: =I

SelectingtheInputTheinputcapacitorreducesthesurgecurrentdrawnfromtheinputsupplyandtheswitchingnoisefromthedevice.Theinputcapacitorimpedanceattheswitchingfrequencyshouldbelessthantheinputsourceimpedancetopreventhighfrequencyswitchingcurrentfrompassingthroughtheinput.CeramiccapacitorswithX5RorX7RdielectricsarehighlyrecommendedbecauseoftheirlowESRandsmalltemperaturecoefficients.Formostapplications,a4.7µFcapacitorissufficient.SelectingtheOutputTheoutputcapacitorkeepstheoutputvoltageripplesmallandensuresfeedbackloopstability.Theoutputcapacitorimpedanceshouldbelowattheswitchingfrequency.CeramiccapacitorswithX5RorX7RdielectricsarerecommendedfortheirlowESRcharacteristics.Formostapplications,a22µFceramiccapacitorwillbePCBLayoutPCBlayoutisveryimportanttoachievestableoperation.PleasefollowtheseguidelinesandtakeFigure2forreferences.KeepthepathofswitchingcurrentshortandminimizetheloopareaformedbyInputcap,high-sideMOSFETandschottkydiode.KeeptheconnectionofschottkydiodebetweenSWpinandinputpowergroundasshortandwideaspossible.Ensureallfeedbackconnectionsareshortanddirect.Placethefeedbackresistorsandcompensationcomponentsasclosetothechipaspossible.RouteSWawayfromsensitiveanalogareassuchasFB.ConnectIN,SW,andespeciallyGNDrespectivelytoalargecopperareatocoolthechiptoimprovethermalperformanceUnderlightloadconditionsbelow100mA,alargerinductanceisrecommendedforimprovedefficiency.SeeTable2forsuggestedinductors.Alsonotethatthemaximumrecommendedloadcurrentis1Aifthedutycycleexceeds35%.

andlong-termreliability.ForsinglelayerPCB,exposedpadshouldnotbesoldered.123Anexternalbootstrapdiodemayenhancetheefficiencyoftheregulator,theapplicableconditionsofexternalBSTdiodeare:123BSTGNDFBVBSTGNDFBDutycycleishigh:D=VOUT654Inthesecases,anexternalBSTdiodeisrecommendedfromtheoutputofthevoltageregulatortoBSTpin,asshowninFig.3654Figure2—PCB

5Vor3Figure3—AddOptionalExternalBootstrapDiodetoEnhanceEfficiencyTherecommendedexternalBSTdiodeisIN4148,andtheBSTcapis0.1~1µF.Table2—SuggestedSurfaceMountPartMaxRating(A)LxWxH6x6.3x5.1x5.1xWurth5.8x5.8xTYPICALAPPLICATION55BS4OFF 6D3canbeinstalledifVIN<D2canbeinstalledifVOUT<NoneedforbothD2and3B230A-13-Figure4—1.4MHz,3.3VOutputat1AStep-Down56OFF432Figure5—WhiteLEDDriverPACKAGE

TSOT23-641.50641.5013APINTOP RECOMMENDEDLAND 1.00SEATING0.95 SEEDETAILFRONT SIDEDETAIL

ALLDIMENSIONSAREINGAUGE0.25 GAUGE0.25 PACKAGEWIDTHDOESNOTINCLUDEINTERLEADFLASHORPROTRUSION. LEADCOPLANARITY(BOTTOMOFLEADSAFTERFORMING)SHALLBE0.10MILLIMETERSMAX.DRAWINGCONFORMSTOJEDECMO-193,VARIATIONDRAWINGISNOTTO PIN1ISLOWERLEFTPINWHENREADINGTOPMARKFROMLEFTTORIGHT,(SEEEXAMPLETOPMARK)64 64 13APINTOP RECOMMENDEDLAND

0.95

1.45SEATING

FRONT SIDEDETAIL

ALLDIMENSIONSAREINGAUGE0.25GAUGE0.25 0o- PACKAGEWIDTHDOESNOTINCLUDEINTERLEADFLASHORPROTRUSION. LEADCOPLANARITY(BOTTOMOFLEADSAFTERFORMING)SHALLBE0.10MILLIMETERSMAX.DRAWINGCONFORMSTOJEDECMO-193,VARIATIONDRAWINGISNOTTO PIN1ISLOWERLEFTPINWHENREADINGTOPMARKFROMLEFTTORIGHT,(SEEEXAMPLETOPMARK)NOTICE:Theinformationinthisdocumentissubjecttochangewithoutnotice.PleasecontactMPSforcurrentspecifications.UsersshouldwarrantandguaranteethatthirdpartyIntellectualPropertyrightsarenotinfringeduponwhenintegratingMPSproductsintoanyapplication.MPSwillnotassumeanylegalresponsibilityforanysaidapplications.采用TSOT23-6封装的1.2A、24V、1.4MHz模拟IC技术的未来描述MP2359是一款具有内置功率MOSFET的单片降压开关模式转换器。它可在宽输入电源范围内实现1.2A峰值输出电流，并具有出色的负载和线路调节能力。电流模式操MP2359需要最少数量的现成标准外部组件。MP2359采用TSOT23-6和SOT23-6封装。1.2A0.35。内部功率MOSFET开关稳定，具有低ESR输出陶瓷电容器，效率高达0.1μA关断模式固定1.4MHz频率热关断逐周期过流保护4.5V至24V宽工作输入范围输出可在0.81V至15V范围内调节采用TSOT23-6和SOT23-6封装应用分布式电源系统电池充电器-用于线性稳压器WLED驱动器的稳压器有关MPS绿色状态，请访问MPS网站的质量保证部分。“MPS”和“模拟IC技术的未来”是MonolithicPowerSystems,Inc.的注册商标。典型应用效率与负载电流的关系12VVOUT6050403020100.010.11负载电流MP2359修订版1.212011年7月18日MPS2011年MPS。版MP2359–采用TSOT23-6封装的1.2A、24V、1.4MHz降压转换器订购信息部件号封装顶部标记自由空气温度(TA)MP2359DJ*TSOT23-6F8-40°C至+85°CMP2359DT**SOT23-6J6-40°C至+85°C式，添加后缀–Z（例如M2359DJ–Z）；对于符合RoHS标准的封装，请添加后缀–LF（例如MP2359DJ–LF–Z）**对于卷带式封装，请添加后缀–Z（例如M2359DT–Z）；对于符合RoHS标准的包装，请添加后缀–LF（例如MP2359DT–LF–Z）封装参考顶视图1.2.3.SWGNDINFBEN电源电压VIN26V27VVSW+6V-0.3V至+6V连续功耗(TA=+25°C)(TSOT23-60.568WSOT23-……0.568W结温………………150°C引线温度..260°C存储温度-65°C至+150°C建议工作条件(电源电压VIN4.5V至24V输出电压0.81V至15V环境温度-40°C至+85°CEN300μA热阻(4)θJAθJCTSOT23-..220..110..℃/WSOT23-6220110..°C/W最大允许功耗是最大结温TJ(MAXθJATA。任何环境温度下的最大允许连续功耗计算公式为在JESD51-7、4层PCBMP2359修订版1.21www.MonolithicP2011年7月18日MPS2011年MPS电气特性VIN=12V，TA=+25°C参数符号条件最小值典型值最大值单位反馈电压VFB4.5V≤VIN≤24V0.7900.8100.830V反馈电流IFBVFB=0.8V0.1μA接通电阻(5)RDS(ON)0.35.开关漏电流VEN=0V，VSW=0V10μA电流限制(5)1.8A振荡器频率fSWVFB=0.6V1.41.7MHz折返频率VFB=0V460kHz最大占空比VFB=0.6V87最短导通时间(5)tON100ns欠压锁定阈值上升2.52.83.1V欠压锁定阈值迟滞150mVEN输入低电压0.4VEN输入高电压1.2VEN输入电流VEN=2V2.1μAVEN=0V0.1电源电流（关断）ISVEN=0V0.11.0μA电源电流（静态）IQVEN=2V，VFB=1V1.0mA热关断(5)150°C1BST引导程序。SWBS引脚之间连接有一个电容器，以在电GND接地。该引脚是稳压输出电压的参考电压。因此，必须注意其布局。该节点应放置在D1至C1接地路径之外，以防止开关电流尖峰将电压噪声引入器件中。脸书反馈。从输出到GND的外部电阻分压器（分接至FB引脚）可设置输出电压。为了防止在短路故障情况下电流限制失控，频率折返比较器会在FB电压低于250mV时降低振荡器频率。4EN开/关控制输入。将EN拉至1.2V以上以开启器件。要自动启用，请连接100k。该引脚和Vin引脚之间的电阻。IN电源电压。MP2359的工作电压为+4.5V至+24V未稳压输入。需要C1来防止输入处出现大SWMP2359修订版1.212011年7月18日MPS2011年MPS。版典型性能特性VIN=12V，VOUT=3.3V，L=4.7μH，C1=10μF，C2=22μF，TA=+效率与效率与负载电流的关系负载电流VIN=12VVIN=24VVOUT=5V反馈电压（％）（％）00.010.11100.010.1110负载电流(A)负载电流反馈电压与开关频率与芯片温度的关系芯片温度开关频率模具温度(OC)模具温度MP2359修订版1.212011年7月18日MPS2011年MPS。版典型性能特性（续）除非另有说明，VIN=12V，VOUT=3.3V，L=4.7μH，C1=10μF，C2=22μF，TA=+25oC。电流限制与稳态测试占空比IOUT0.5A3.050mV10V/格。1A/格。IL500mA0.5ILOAD1A/格。0占空比短路进入短路恢复通过启用空载电流限制(A)启动VEN5V/格。VOUT1V/格。VSW10V/格。IL1A/格。500mA通过使能启动通过使能关闭通过使能关闭IOUT=1A阻性负载无负载IOUT=1A阻性负载VENVENVEN5V/5V/5V/VOUT2V/格。VOUT1V/格。VSW10V10V1A/1A/MP2359修订版1.212011年7月18日MPS2011年MPS。版操作MP2359是一款电流模式降压稳压器。也就是说，EA输出电压与峰值电感电流成正比。一个周期开始时，M1截止。EA输出电压高于电流检测放大器输出，电流比较器输出较低。1.4MHzCLK信号的上升沿设置RS触发器。其输出开启M1，从而将SW引脚和电感器连接至输入PWMEA电压时，RS触发器复位且M1关闭。外部肖特基整流二极管(D1)传导电感电流。INENFBGND如果电流检测放大器输出和斜率补偿信号之和在整个周期内不超过EA输出，则CLK的下降沿将复位触发器。误差放大器的输出对反馈和0.81V带隙基准之间的电压差进行积分。极性使得FB引脚电压低于0.81V会增加EA输出电压。由于EA输出电压与峰值电感电流成正比，因此其电压的增加也会增BST软件MP2359修订版1.212011年7月18日MPS2011年MPS。版应用信息设置输出电压外部电阻分压器用于设置输出电压（参见首页原理图）。表1显示了常见输出电压的电阻器选择列表。反馈电阻器R1还通过内部补偿电容器设置反馈环路带宽（见图1）。R2可由下式确定：R1R2=10.81V表1—通用输出电压VOUT(V)R1(k.)R2(k549.9(1%)9.53选择电感器对于大多数应用，建议选择直流电流额定值至少比最大负载电流高25%的1μH至10μH电感器。为了获得最高效率，电感器的直流电阻应小于200m。有关建议的表面贴装电感器，请参阅表2V×(V.输出输入输出LV×ΔI×fINLSWΔIL选择电感纹波电流为最大负载电流的30%。最大电感峰值电流的计算公式为：