Step-upDC/DCConverter,ME2108Series GeneralDescription Features ME2108SeriesisaPFMStep-upDC/DCconverterLowrippleandlownoise ICwithlowsupplycurrentbyCMOSprocess.HighOperatingvoltagerange：0.9V~6.5V frequencynoisethatursduringswitchingisOutputvoltagerange：2.0V~7.0V(step0.1V) reducedbyusingadvancedcircuitdesigned,outputOutputvoltageuracy：±2.5% voltageisprogrammablein0.1VstepsbetweenOutputCurrent：IfVIN=3.0VandVOUT=5.0V,then 2.0~7.0Vandmaximumfrequencyis180KHz(TYP.). IOUT=400mA Alowripple,highefficiencystep-upDC/DCconvertercanbeconstructedofME2108Xxxwithonlythree Lowstartvoltage：≤0.9V(atIOUT=1mA)Maximumoscillatorfrequency：180KHz(TYP.) ponents.AlsoavailableisaCE(chipHighEfficiency：85%(TYP.) enable)functionthatreducepowerdissipation Duringshut-downmode.ME2108Xxxissuitablefor usewithbattery-poweredinstrumentswithlownoise andlowsupplycurrent. TypicalApplication Powersourceforbattery-poweredequipmentPowersourceforwirelessmouse,wireless keyboard,toys,cameras,camcorders,VCRs,PDAs,andmunicationequipmentPowersourceforapplianceswhichrequirehighercellvoltagethanthatofbatteriesusedintheappliances Package 3-pin:SOT23-
3、SOT89-
3、TO925-pin:SOT23-
5 V12.0 1/14 TypicalApplications ME2108 Forusebuildintransistor Forusechipenable Foruseexternaltransistor Components：Inductor：33uH(Sumida)Diode：IN5817、IN5819Capacitor：47uF/16V(TantalumCapacitor)NMOS：MEM2302、AAT9460、XP151、XP161 Foruseexternaltransistor&chipenable V12.0 2/14 SelectionGuide ME2108XXXXXG EnvironmentmarkPackage: P-SOT89-3M5-SOT23-
5 OutputVoltage FunctionProductTypeProductSeriesMicrone ME2108 Productseries SwitchTransistor CEFunction Featutes VoltagePackage Buildin ME2108A28PG No Lx 2.8 SOT89-
3 Transistor Buildin ME2108A30M3G No Lx 3.0 SOT23-
3 Transistor Buildin ME2108A33TG No Lx 3.3 TO-92 Transistor External ME2108B33M3G No Ext 3.3 SOT23-
3 Transistor Build
in ME2108C36M5G Yes Lx 3.6 SOT23-
5 Transistor External ME2108D50M5G Yes Ext 5.0 SOT23-
5 Transistor External ME2108F33M5G Yes Ext 3.3 SOT23-
5 Transistor NOTE: At
present,therearefivekindsofvoltagevalue:2.7V、2.8V、3.0V、3.3V、3.6V、4.0V、5.0V、5.6V。
Ifyouneedothervoltageandpackage,pleasecontactoursalesstaff。
V12.0 3/14 PinConfiguration ME2108 ME2108AXX PINNumber SOT23-
3 SOT89-
3 TO92
1 1
1 3
2 3
2 3
2 ME2108BXX PINNumber SOT23-
3 SOT89-
3 1
1 3
2 2
3 PinName VssVoutLx Function GroundOutputvoltagemonitor,ICinternalpowersupply Switch PinName VssVoutExt Function GroundOutputvoltagemonitor,ICinternalpowersupply Externalswitchtransistordrive ME2108CXX PINNumber SOT23-
5 SOT89-
5 4
5 2
2 5
4 1
3 3
1 PinName VssVoutLxCENC Function GroundOutputvoltagemonitor,ICinternalpowersupply SwitchChipenable NC ME2108DXXPINNumberSOT23-542513 PinName VssVoutExtCENC Function GroundOutputvoltagemonitor,ICinternalpowersupply ExternalswitchtransistordriveChipenableNC V12.0 4/14 ME2108FPINNumberSOT23-512345 BlockDiagram PinName FBVddNCVssEXT ME2108 FunctionFeedBackOutputvoltagemonitor,ICinternalpowersupply NCGroundExternalswitchtransistordrive AbsoluteMaximumRatings PARAMETER VINInputVoltageLxPinvoltageEXTPinvoltageCEPinvoltageLxPincurrentEXTPincurrent Vddinputvoltage ContinuousTotalPowerDissipation SOT23SOT89TO92 OperatingAmbientTemperature StorageTemperature Solderingtemperatureandtime SYMBAL VINVLXVEXTVCEILXIEXTVddPd Pd PdTOprTstgTsolder RATINGS 6.56.5-0.3~Vout+0.3-0.3~Vout+0.3600±306.5300 500500-25~+85-40~+125260℃,10s UNITS VVVVmAmAVmW mWmW℃℃ V12.0 5/14 ME2108 ElectricalCharacteristics Measuringconditions：Unlessotherwisespecified,VIN=Vout×0.6，VSS=0V，IOUT=10mA，Topt=25℃。
ME2108Axx/CxxFosc=180kHz SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VOUTVstartVholdIDD1 OutputVoltage OscillationStart-upVoltage OscillationHoldVoltage SupplyCurrent1 IOUT=1mA，VIN：0→2VIOUT=1mA，VIN：2→0V NoponentVout=Vout×0.95, Vout×0.975 Vout0.80.4550 Vout×V 1.025 0.9
V V µ
A IDD2 SupplyCurrent2 Vout=Vout+0.5V
9 µ
A ILX ILXleakFoscMaxdtyEFFI LxSwitchingCurrent LxLeakageCurrentOscillationFrequency DutyRatioEfficiency VLX=0.4V,Vout=Vout×0.95 Vout=VLX=6VVout=setVout×0.95 on(VLX“L”)side 360 mA 0.5 µ
A 180 kHz 84 % 85 % ME2108Bxx/DxxFosc=180kHz SYMBOL PARAMETER VOUTVstartVholdIDD1 OutputVoltage OscillationStart-upVoltage OscillationHoldVoltage SupplyCurrent1 IDD2 SupplyCurrent2 ILX ILXleakFoscMaxdtyEFFI LxSwitchingCurrent LxLeakageCurrentOscillationFrequency DutyRatioEfficiency CONDITIONS IOUT=1mA，VIN：0→2VIOUT=1mA，VIN：2→0VNoponentVout=Vout×0.95,Vout=Vout+0.5VVLX=0.4V,Vout=Vout×0.95Vout=VLX=6VVout=setVout×0.95on(VLX“L”)side MINVout×0.975 TYPVout0.80.458012360 1808485 MAXVout×1.025 0.9 0.5 UNITSV
V V µAµAmAµAkHz%% V12.0 6/14 ME2108 ME2108FVFB=3.3V,Fosc=180kHz SYMBOL PARAMETER CONDITIONS MIN TYP VFBVstartVholdIDD1 OutputFeedbackVoltage OscillationStart-upVoltage OscillationHoldVoltage SupplyCurrent1 IOUT=1mA，VIN：0→2VIOUT=1mA，VIN：2→0V NoponentVout=Vout×0.95, 3.22 3.30.80.4580 IDD2 SupplyCurrent2 Vout=Vout+0.5V 10 VLX=0.4V, ILX LxSwitchingCurrent Vout=Vout×0.95 360 ILXleak LxLeakageCurrent Vout=VLX=6V FoscyVout=setVout×0.95180 Maxdty DutyRatio on(VLX“L”)side 84 EFFI Efficiency 85 Note：
1、DiodeuseSchottkydiodesuchasIN5817orIN5819(forwardvoltagedrop:0.2V)
2、Inductor：33μH（r<0.5Ω）
3、Capacitor：Tantalumtype100μ
F MAX3.380.9 0.5 UNITSV
V V µAµAmAµAkHz%% OperationDescription ME2108step-upDC/DCconverterchargesenergyintheinductorwhenLxTransistorison,anddischargestheenergywiththeadditionoftheenergyfrominputpowersourcethereto,sothatahigheroutputvoltagethantheinputvoltageisobtained.Followingistheoperationdiagram. SwitchingDC/DCStepupConverteroperatingprocess V12.0 7/14 ME2108 SelectionofPeripheralComponentsandApplicationNotes Powersourceforbattery-poweredequipmentPowersourceforwirelessmouse,wirelesskeyboard,toys,cameras,camcorders,VCRs,PDAs,and municationequipmentPowersourceforapplianceswhichrequirehighercellvoltagethanthatofbatteriesusedintheappliancesponentsshouldbeselectedcarefullybecausetheyaregreatlyaffecttheperformancesof ME2108：Usecapacitorwithacapacityof10μFormore(toosmallcapacitywillleadtohighoutputripple),and withgoodfrequencycharacteristics(itisbettertouseTantalumtype).Besides,itismendedtheuseofacapacitorwithanallowablevoltagewhichisatleastthreetimestheoutputsetvoltage.Thisisbecausetheremaybethecasewhereaspike-shapedhighvoltageisgeneratedbytheinductorwhenLxtransistoristurnedOFF.Choosesuchaninductorthathassufficientlysmalld.c.resistanceandlargeallowablecurrent,andhardlyreachesicsaturation.Whentheinductancevalueoftheinductorissmall,theremaybethecasewhereILXexceedstheabsolutemaximumratingsatthemaximumload.UseadiodeofaSchottkytypewithhighswitchingspeed.PCBLayout：SetponentsascloseaspossibletotheICandminimizetheconnectionbetweenponentsandtheIC.Inparticular,whenanponentisconnectedtoVOUTPin,makeminimumconnectionwiththecapacitor.MakeVsspinsufficientgrounding,otherwise,thezerolevelwithinICwillvariedwiththeswitchingcurrent.ThismayresultinunstableoperationofIC. TypeCharacteristics
（1）OutputCurrentVS.OutputVoltage（Ta=25°C）
（2）OutputCurrentVS.Efficiency（Ta=25°C） OutputVoltage(V)Efficiency(%) OutputCurrentVS.OutputVoltage 3.93.32.72.11.50.90.3
0 VIN=0.9V 50 ME2108A33 3.3V 1.5V 1.2V 100 150 200 250 300 OutputCurrent(mA) OutputCurrentVS.Efficiency100 90 ME2108A33 80 7060 501.2V 40 VIN=3.0V1.5V 30
0 50 100 150 200 250 300 OutputCurrent(mA) V12.0 8/14 ME2108
（3）SupplyCurrentVS.InputVoltage（Ta=25°C）
（4）InputCurrentVS.OutputVoltage（Ta=25°C） ME2108A33 InputCurrent(uA) InputCurrentVS.OutputVoltage 80 70 60 L＝33uHCout=100uF 50 Diode:1N5717orIN5819 40 30 20 10 02.733.33.63.94.24.54.85.15.4 OutputVoltage(V)
（5）InputCurrent1VS.OutputVoltage（Ta=25°C）
（6）InputCurrent2VS.OutputVoltage（Ta=25°C） VDD=VOUT×0.95 VDD=VOUT+0.5
（7）OscillationfrequencyVS.OutputVoltage
（8）DutyCycleVS.OutputVoltage（Ta=25°C） V12.0 9/14 PackagingInformation ●SOT23-
5 ME2108 Millimeters DIM Min Max
A 1.05 1.45 A1
0 0.15 A2 0.9 1.3 A3 0.6 0.7 b 0.25 0.5 c 0.1 0.23
D 2.82 3.05 e1 1.8 2.0
E 2.6 3.05 E1 1.5 1.75 e 0.85 1.05
L 0.25 0.6 L1 0.59 0.6 θ
0 8° c1 0.2 0.25 Min
0.0413 00.03540.02360.00980.00390.1110.07090.10240.05910.03350.00980.0232 00.0079 Inches Max0.05710.00590.05120.02760.01970.12280.12010.07870.12010.06890.04130.02360.0236 8°0.0098 V12.0 10/14 ●SOT89-
3 ME2108 Millimeters DIM Min Max
A 1.4 1.6 b 0.32 0.52 b1 0.4 0.58 c 0.35 0.45
D 4.4 4.6 D1 1.55 1.75 D2 1.75REF e1 2.95 3.05
E 2.3 2.6 E1 3.94 4.4 E2 1.9REF e 1.5TYP
L 0.8 1.2 θ 45° Min
0.05510.01260.01570.01380.17320.061 0.11610.09060.1551 0.0315 InchesMax0.063 0.02050.02280.017720.18110.06890.0689REF0.12010.10230.17320.0748REF0.0591TYP0.047245° V12.0 11/14 ●SOT23-
3 ME2108 Millimeters DIM Min Max
A 1.05 1.45 A1
0 0.15 A2 0.9 1.3 A3 0.6 0.7 b 0.25 0.5 c 0.1 0.25
D 2.82 3.05
E 2.6 3.05 E1 1.5 1.75 e 0.85 1.05
L 0.25 0.6 L1 0.59 0.6 θ
0 8° c1 0.2 0.25 Min
0.0413 00.03540.02360.00980.00390.1110.10240.05910.03350.00980.0232 00.0079 Inches Max0.05710.00590.05120.02760.01970.00980.12010.12010.06890.04130.02360.0236 8°0.0098 V12.0 12/14 ●TO92 ME2108 Millimeters DIM Min Max
A 3.3 3.7 A1 1.1 1.4 b 0.38 0.55 c 0.36 0.51
D 4.3 4.7 D1 3.43
一 E 4.3 4.7 e 2.4 2.7 e1 2.44 2.64
L 14.1 14.5 h
0 0.38 Φ
一 1.6 Min
0.12990.04330.0150.01420.16930.1350.16930.09450.09610.5551 0一 Inches Max0.14570.05510.02170.02010.185 一0.1850.10630.10390.57090.0150.063 V12.0 13/14 ME2108 Theinformationdescribedhereinissubjecttochangewithoutnotice.NanjingMicroOneElectronicsIncisnotresponsibleforanyproblemscausedbycircuitsordiagrams describedhereinwhoserelatedindustrialproperties,patents,orotherrightsbelongtothirdparties.Theapplicationcircuitexamplesexplaintypicalapplicationsoftheproducts,anddonotguaranteetheessofanyspecificmass-productiondesign.Useoftheinformationdescribedhereinforotherpurposesand/orreproductionorcopyingwithouttheexpresspermissionofNanjingMicroOneElectronicsIncisstrictlyprohibited.Theproductsdescribedhereincannotbeusedaspartofanydeviceorequipmentaffectingthehumanbody,suchasexerciseequipment,medicalequipment,securitysystems,gasequipment,oranyapparatusinstalledinairplanesandothervehicles,withoutpriorwrittenpermissionofNanjingMicroOneElectronicsInc.AlthoughNanjingMicroOneElectronicsIncexertsthegreatestpossibleefforttoensurehighqualityandreliability,thefailureormalfunctionofsemiconductorproductsmayur.Theuseroftheseproductsshouldthereforegivethoroughconsiderationtosafetydesign,includingredundancy,fire-preventionmeasures,andmalfunctionprevention,topreventanyidents,fires,munitydamagethatmayensue. V12.0 14/14