LTC3429/LTC3429B600mA, 500kHz MicropowerSynchronous Boost Converterwith Output DisconnectDESCRIPTIO■■■■■■■■■■■■■■■■UAPPLICATIO S■■■■■■Up to 96% EfficiencyTrue Output Load DisconnectInrush Current Limiting and Internal Soft-StartLow Voltage Start-Up: 0.85VAutomatic Burst Mode® Operation with IQ ~ 20µAContinuous Switching at Light Loads (LTC3429B)Internal Synchronous RectifierCurrent Mode Control with Internal CompensationShort-Circuit Protection500kHz Fixed Frequency SwitchingInput Range: 0.5V to 4.4VOutput Range: 2.5V to 4.3V (Up to 5V with Schottky)Shutdown Current: <1µAAntiringing Control Minimizes EMITiny External ComponentsLow Profile (1mm) SOT-23 PackageThe LTC®3429/LTC3429B are high efficiency synchro-nous, fixed frequency, step-up DC/DC converters with trueoutput load disconnect, inrush current limiting and soft-start in a low profile 6-lead ThinSOTTM package. Thesedevices are capable of supplying 100mA from a single AAcell input or 250mA from a 2-cell AA with a 3.3V output.A switching frequency of 500kHz minimizes overall solu-tion footprint by allowing the use of tiny, low profileinductors and ceramic capacitors. Current mode PWMcontrol with internal compensation reduces external partscount thereby saving critical board real estate. The LTC3429shifts automatically to power saving Burst Mode operationat light loads while the LTC3429B features continuousswitching at light loads. Antiringing control circuitry re-duces EMI concerns by damping the inductor in discon-tinuous mode.The devices also feature low shutdown current of under1µA. The true output disconnect feature allows the outputto be completely discharged in shutdown. It also limits theinrush of current during start-up, minimizing surge cur-rents seen by the input supply., LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Burst Mode is a registered trademark of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation.MP3 PlayersDigital CamerasLCD Bias SuppliesHandheld InstrumentsWireless HandsetsGPS ReceiversTYPICAL APPLICATIO4.7µH100VIN = 3V90EFFICIENCY (%)+EFFICIENCYVIN = 2.4V2-CELLAA4.7µFVINSWVOUT1.02MLTC3429VOUT3.3V250mA10µF80706050 OFFONSHDNGNDFB604k3429 F01aFigure 1. 2-Cell to 3.3V Synchronous Boost Converter400.1U2-Cell to 3.3V Efficiency10010POWER LOSS (W)FEATURESU10.1VIN = 3V0.01VIN = 2.4VPOWER LOSS0.0010.000110003429 F01b110100OUTPUT CURRENT (mA)3429fa1
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LTC3429/LTC3429BABSOLUTE AXI U RATI GS(Note 1)UUWPACKAGE/ORDER I FOR ATIOTOP VIEWSW 1GND 2FB 36 VIN5 VOUT4 SHDNVIN Voltage.............................................. –0.3V to 4.4VSW Voltage................................................. –0.3V to 6VSHDN, FB Voltage....................................... –0.3V to 6VVOUT........................................................... –0.3V to 6VOperating Temperature Range (Note 2)..–40°C to 85°CStorage Temperature Range................... –65°C to 150°Lead Temperature (Soldering, 10 sec)..................300°CELECTRICAL CHARACTERISTICSPARAMETERMinimum Start-Up VoltageMinimum Operating VoltageOutput Voltage Adjust RangeFeedback VoltageFeedback Input CurrentQuiescent Current (Burst Mode Operation)Quiescent Current (Shutdown)Quiescent Current (Active)NMOS Switch LeakagePMOS Switch LeakageNMOS Switch On ResistancePMOS Switch On ResistanceNMOS Current LimitBurst Mode Operation Current ThresholdCurrent Limit Delay to OutputMax Duty CycleSwitching FrequencySHDN Input HighSHDN Input LowSHDN Input CurrentSoft-Start TimeThe ● denotes the specifications which apply over the full operatingtemperature range, otherwise specifications are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, unless otherwise specified.CONDITIONSILOAD = 1mA, VOUT = 0VSHDN = VIN (Note 3)(Note 5)●VFB = 1.25VVFB = 1.4V (Note 4)VSHDN = 0V, Not Including Switch Leakage, VOUT = 0VMeasured on VOUT, NonswitchingVSW = 5VVSW = 5V, VOUT = 0VL = 4.7µH (LTC3429 Only)VFB = 1.15V●●VSHDN = 5.5V SHDN to 90% of VOUTNote 1: Absolute Maximum Ratings are those values beyond which the lifeof a device may be impaired.Note 2: The LTC3429ES6/LTC3429BES6 are guaranteed to meetperformance specifications from 0°C to 70°C. Specifications over the–40°C to 85°C operating temperature range are assured by design,characterization and correlation with statistical process controls.2
UWWWORDER PARTNUMBERLTC3429ES6LTC3429BES6S6 PART MARKINGLTH5LTBMSS6 PACKAGE6-LEAD PLASTIC TSOT-23TJMAX = 125°C, θJC = 102°C/WConsult LTC Marketing for parts specified with wider operating temperature ranges.MINTYP0.850.5MAX10.6551.2685030155055UNITSVVVVnAµAµAµAµAµAΩΩmAmAns%2.51.1921.2301200.013800.10.10.350.456008501.2540803801905006200.35kHzVVµAms0.012.51Note 3: Minimum VIN operation after start-up is only limited by thebattery’s ability to provide the necessary power as it enters a deeplydischarged state.Note 4: Burst Mode operation IQ is measured at VOUT. Multiply this valueby VOUT/VIN to get the equivalent input (battery) current.Note 5: For applications where VOUT > 4.3V, an external Schottky diode isrequired. See the Applications Information.3429fa元器件交易网www.cecb2b.com
LTC3429/LTC3429BTYPICAL PERFOR A CE CHARACTERISTICS (TA = 25°C unless otherwise specified)Single-Cell to 3.3V Efficiency(LTC3429 Only)1009010010100VIN = 3V90EFFICIENCYVIN = 2.4V10908070605040VIN > VOUTPMOS LDOMODE0.51.52.53.5INPUT VOLTAGE (V)4.53429 G05VIN = 1.5VEFFICIENCYVIN = 1.2VEFFICIENCY (%)EFFICIENCY (%)706050400.1VIN = 1.2VVIN = 1.5VPOWER LOSS0.10.01706050400.1VIN = 2.4VVIN = 3VPOWER LOSS0.10.010.0010.000110003429 G010.0010.000110003429 G02110100OUTPUT CURRENT (mA)110100OUTPUT CURRENT (mA)EFFICIENCY (%)80100902-Cell to 5V Efficiency(LTC3429 Only)VIN = 3VEFFICIENCYVIN = 2.4VVIN = 2.4VVIN = 3VPOWER LOSSOUTPUT CURRENT (mA)EFFICIENCY (%)EFFICIENCY (%)80706050400.1110100OUTPUT CURRENT (mA)No Load Input Currentvs Input Voltage (LTC3429 Only)1000L = 4.7µHOUTPUT CURRENT (mA)INPUT CURRENT (µA)400VOUT = 3.3V300VOUT = 5V200100INPUT VOLTAGE (V)VOUT = 5V100VOUT = 3.3V100.91.41.92.42.93.4INPUT VOLTAGE (V)UW13429 G032-Cell to 3.3V Efficiency(LTC3429 Only)100100Efficiency vs Input VoltageVOUT = 3.3VIOUT = 50mAPOWER LOSS (W)POWER LOSS (W)8011001010090Li-Ion to 5V Efficiency(LTC3429 Only)VIN = 4.2V10010Burst Mode Output CurrentThreshold vs Input Voltage(LTC3429 Only)35302520VOUT = 3.3V15VOUT = 5V10500.9L = 4.7µHEFFICIENCY10.10.0180706050400.1VIN = 3.6VPOWER LOSS (W)10.1VIN = 4.2VPOWER LOSS0.010.0010.00011000POWER LOSS (W)VIN = 3.6V0.0010.000110003429 G04110100OUTPUT CURRENT (mA)1.43.41.92.42.9INPUT VOLTAGE (V)3.94.43429 G06Maximum Load CurrentCapability at Output 4% BelowRegulation Point600500L = 4.7µH1.91.71.51.31.10.90.7Minimum Start-Up Input Voltagevs Load CurrentCURRENTSINK LOADRESISTORLOAD3.94.400.5133.51.522.5INPUT VOLTAGE (V)44.5050100OUTPUT CURRENT (mA)1503429 G093429 G073429 G083429fa3
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LTC3429/LTC3429BTYPICAL PERFOR A CE CHARACTERISTICS (TA = 25°C unless otherwise specified)Output Voltage vs Temperature3.443.403.36VIN = 1.5VIOUT = 30mANORMALIZED FREQUECYQUIESCENT CURRENT (µA)VOUT (V)3.323.283.243.203.16204060–60–40–290TEMPERATURE (°C)SW Pin Fixed FrequencyContinuous Mode OperationVSW1V/DIVVIN = 1.5VVOUT = 3.3VIOUT = 50mAL = 10µHCOUT = 10µFCPL = 150pF200ns/DIVOutput Voltage TransientResponseVOUT100mV/DIVAC-COUPLEDIOUT90mA40mAVIN = 1.5V100µs/DIVVOUT = 3.3VIOUT = 40mA TO 90mA STEPL = 10µHCOUT = 10µFCPL = 150pF3429 G164
UW803429 G10Normalized Oscillator Frequencyvs Temperature1.024035Burst Mode Quiescent Currentvs Temperature (LTC3429 Only)1.00VOUT = 5V30252015105VOUT = 3.3V0.980.960.941000.92–60–40–200204060TEMPERATURE (°C)801000204060–60–40–200TEMPERATURE (°C)801003429 G113429 G12SW Pin Discontinuous ModeAntiringing OperationFixed Frequency and Burst ModeOperation (LTC3429 Only)VSW1V/DIVVOUT100mV/DIVAC-COUPLEDIOUT50mA120µA3429 G13VIN = 1.5VVOUT = 3.3VIOUT = 20mAL = 10µHCOUT = 10µFCPL = 150pF200ns/DIV3429 G14VIN = 1.5V5ms/DIVVOUT = 3.3VIOUT = 120µA TO 50mA STEPL = 10µHCOUT = 10µFCPL = 150pF3429 G15Inrush Current Controland Soft-StartInrush Current Controland Soft-StartVOUT1V/DIVVOUT2V/DIVINDUCTORCURRENT100mA/DIVINDUCTORCURRENT200mA/DIVVIN = 1.5VVOUT = 3.3VIOUT = 10mAL = 4.7µHCOUT = 10µFCPL = 100pF500µs/DIV3429 G17VIN = 2.5VVOUT = 5VIOUT = 50mAL = 4.7µHCOUT = 10µFCPL = 100pF2ms/DIV3429 G183429fa元器件交易网www.cecb2b.com
LTC3429/LTC3429BPI FU CTIO SSW (Pin 1): Switch Pin. Connect inductor between SWand VIN. Keep these PCB trace lengths as short and wideas possible to reduce EMI and voltage overshoot. If theinductor current falls to zero, or SHDN is low, an internal150Ω antiringing switch is connected from SW to VIN tominimize EMI.GND (Pin 2): Signal and Power Ground. Provide a shortdirect PCB path between GND and the (–) side of the outputcapacitor(s).FB (Pin 3): Feedback Input to the gm Error Amplifier.Connect resistor divider tap to this pin. The output voltagecan be adjusted from 2.5V to 5V by:VOUT = 1.23V • [1 + (R1/R2)]SHDN (Pin 4): Logic Controlled Shutdown Input.SHDN = High: Normal free running operation, 500kHztypical operating frequency.SHDN = Low: Shutdown, quiescent current <1µA.Output capacitor can be completely discharged throughthe load or feedback resistors. A 150Ω resistor isinternally connected between SW and VIN.VOUT (Pin 5): Output Voltage Sense Input and Drain of theInternal Synchronous Rectifier MOSFET. Bias is derivedfrom VOUT. PCB trace length from VOUT to the output filtercapacitor(s) should be as short and wide as possible. VOUTis completely disconnected from VIN when SHDN is lowdue to the output disconnect feature.VIN (Pin 6): Battery Input Voltage. The device gets itsstart-up bias from VIN. Once VOUT exceeds VIN, biascomes from VOUT. Thus, once started, operation is com-pletely independent from VIN. Operation is only limited bythe output power level and the battery’s internal seriesresistance.BLOCK DIAGRA L1+1V TO 4.4V6VINVOUTGOODSTART-UPOSCABA/BMUXPWMCONTROLRAMPGEN500kHzPWMCOMPARATORSYNCDRIVECONTROLSLOPECOMPΣSLEEPBurst ModeOPERATIONCONTROLCC150pFCP22.5pFSHDN4SHUTDOWNCONTROLSHUTDOWN2GND3429 BD+RC80kgmERRORAMP––+––+WUUUCIN1SWVIN2.3V0.45ΩWELLSWITCHVOUT52.5V TO 5V0.35ΩCPL(OPTIONAL)R1CURRENTSENSEFB31.23VREFR2COUT3429fa5
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LTC3429/LTC3429BUOPERATIOThe LTC3429/LTC3429B are 500kHz, synchronous boostconverters housed in a 6-lead SOT-23 package. Able tooperate from an input voltage below 1V, the device fea-tures fixed frequency, current mode PWM control forexceptional line and load regulation. Low RDS(ON) internalMOSFET switches enable the device to maintain highefficiency over a wide range of load current. Detaileddescriptions of the different operating modes follow.Operation can be best understood by referring to the BlockDiagram.LOW VOLTAGE START-UPThe LTC3429/LTC3429B include an independent start-uposcillator designed to start up at input voltages of 0.85Vtypically. The frequency and duty cycle of the start-uposcillator are internally set to 150kHz and 67% respec-tively. In this mode, the IC operates completely open-loopand the current limit is also set internally to 850mA. Oncethe output voltage exceeds 2.3V, the start-up circuitry isdisabled and normal close-loop PWM operation is initi-ated. In normal mode, the LTC3429/LTC3429B powerthemselves from VOUT instead of VIN. This allows thebattery voltage to drop to as low as 0.5V without affectingthe circuit operation. The only limiting factor in the appli-cation becomes the ability of the battery to supply suffi-cient energy to the output. Soft-start and inrush currentlimiting are provided during start-up as well as normalmode operation.Soft-StartThe LTC3429/LTC3429B provide soft-start by charging aninternal capacitor with a very weak current source. Thevoltage on this capacitor, in turn, slowly ramps the peakinductor current from zero to a maximum value of 850mA.The soft-start time is typically 2.5ms, the time it takes tocharge the capacitor from zero to 1.35V. However, thistime varies greatly with load current, output voltage andinput voltage (see Typical Performance Characteristics,Inrush Current Control and Soft-Start). The soft-startcapacitor is discharged completely in the event of acommanded shutdown or a thermal shutdown. It is dis-charged only partially in case of a short circuit at theoutput.LOW NOISE FIXED FREQUENCY OPERATIONOscillatorThe frequency of operation is internally set to 500kHz.Error AmpThe error amplifier is an internally compensated transcon-ductance type (current output) with a transconductance(gm) = 33 microsiemens. The internal 1.23V referencevoltage is compared to the voltage at the FB pin to generatean error signal at the output of the error amplifier. A volt-age divider from VOUT to ground programs the outputvoltage via FB from 2.5V to 5V using the equation:VOUT = 1.23V • [1 + (R1/R2)]Current SensingLossless current sensing converts the NMOS switchcurrent signal to a voltage to be summed with the internalslope compensation. The summed signal is compared tothe error amplifier output to provide a peak currentcontrol command for the PWM. Peak switch current islimited to approximately 850mA independent of input oroutput voltage. The switch current signal is blanked for60ns to enhance noise rejection.Zero Current ComparatorThe zero current comparator monitors the inductor cur-rent to the output and shuts off the synchronous rectifieronce this current reduces to approximately 27mA. Thisprevents the inductor current from reversing in polaritythereby improving efficiency at light loads.Antiringing ControlThe antiringing control circuitry prevents high frequencyringing of the SW pin as the inductor current goes to zeroin discontinuous mode. The damping of the resonantcircuit formed by L and CSW (capacitance on SW pin) isachieved by placing a 150Ω resistor across the inductor.Synchronous RectifierTo prevent the inductor current from running away, thePMOS synchronous rectifier is only enabled when VOUT >(VIN + 0.1V) and the FB pin is >0.8V.3429fa
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LTC3429/LTC3429BUOPERATIOThermal ShutdownAn internal temperature monitor will start to reduce thepeak current limit if the die temperature exceeds 125°C. Ifthe die temperature continues to rise and reaches 160°C,the part will go into thermal shutdown, all switches will beturned off and the soft-start capacitor will be reset. Thepart will be enabled again when the die temperature dropsby about 15°C.Burst Mode OPERATION (LTC3429 Only)Portable devices frequently spend extended time in lowpower or standby mode, only switching to high powerconsumption when specific functions are enabled. Toimprove battery life in these types of products, it isimportant to maintain a high power conversion efficiencyover a wide output power range. The LTC3429 providesautomatic Burst Mode operation to increase efficiency ofthe power converter at light loads. Burst Mode operationis initiated if the output load current falls below an inter-nally programmed threshold. This threshold has an in-verse dependence on the duty cycle of the converter andalso the value of the external inductor (See Typical Perfor-mance Characteristics, Output Current Burst Mode Thresh-old vs VIN). Once Burst Mode operation is initiated, onlythe circuitry required to monitor the output is kept aliveand the rest of the device is turned off. This is referred toas the sleep state in which the IC consumes only 20µAfrom the output capacitor. When the output voltage droopsby about 1% from its nominal value, the part wakes up andcommences normal PWM operation. The output capacitorrecharges and causes the part to re-enter the sleep stateif the output load remains less than the Burst Modethreshold. The frequency of this intermittent PWM orburst operation depends on the load current; that is, as theload current drops further below the burst threshold, theLTC3429 turns on less frequently. When the load currentincreases above the burst threshold, the LTC3429seamlessly resumes continuous PWM operation. Thus,Burst Mode operation maximizes the efficiency at verylight loads by minimizing switching and quiescent losses.However, the output ripple typically increases to about 2%peak-to-peak. Burst Mode ripple can be reduced, in somecircumstances, by placing a small phase-lead capacitor(CPL) between VOUT and FB pins (refer to the BlockDiagram). However, this may adversely affect the effi-ciency and the quiescent current requirement at lightloads. Typical values of CPL range from 15pF to 220pF.OUTPUT DISCONNECT AND INRUSH LIMITINGThe LTC3429/LTC3429B are designed to allow true outputdisconnect by eliminating body diode conduction of theinternal PMOS rectifier. This allows VOUT to go to zerovolts during shutdown, drawing zero current from theinput source. It also allows for inrush current limiting atstart-up, minimizing surge currents seen by the inputsupply. Note that to obtain the advantage of output discon-nect, there must not be an external Schottky diode con-nected between the SWITCH pin and VOUT.Board layout is extremely critical to minimize voltageovershoot on the SWITCH pin due to stray inductance.Keep the output filter capacitor as close as possible to theVOUT pin and use very low ESR/ESL ceramic capacitorstied to a good ground plane. For applications with VOUTover 4.3V, a Schottky diode is required to limit the peakSWITCH voltage to less than 6V unless some form ofexternal snubbing is employed. This diode must also beplaced very close to the pins to minimize stray inductance.See the Applications Information.SHORT CIRCUIT PROTECTIONUnlike most boost converters, the LTC3429/LTC3429Ballow their output to be short circuited due to the output dis-connect feature. The devices incorporate internal featuressuch as current limit foldback, thermal regulation and ther-mal shutdown for protection from an excessive overloador short circuit. In the event of a short circuit, the internalsoft-start capacitor gets partially discharged. This, in turn,causes the maximum current limit to foldback to a smallervalue. In addition to this, a thermal regulation circuit startsto dial back the current limit farther if the die temperaturerises above 125°C. If the die temperature still reaches160°C, the device shuts off entirely.VIN > VOUT OPERATIONThe LTC3429/LTC3429B will maintain voltage regulationeven if the input voltage is above the output voltage. This3429fa
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LTC3429/LTC3429BUOPERATIOis achieved by terminating the switching of the synchro-nous PMOS and applying VIN statically on its gate. Thisensures that the slope of the inductor current will reverseduring the time current is flowing to the output. Since thePMOS no longer acts as a low impedance switch in thismode, there will be more power dissipation within the IC.This will cause a sharp drop in the efficiency (see TypicalPerformance Characteristics, Efficiency vs VIN). The maxi-mum output current should be limited in order to maintainan acceptable junction temperature.APPLICATIO S I FOR ATIOPCB LAYOUT GUIDELINESThe high speed operation of the LTC3429/LTC3429Bdemands careful attention to board layout. You will not getadvertised performance with careless layout. Figure 2shows the recommended component placement. A largeground pin copper area will help to lower the chip tempera-ture. A multilayer board with a separate ground plane isideal, but not absolutely necessary.VIN123SWVIN6GNDVOUT5FBSHDN4SHDNVOUT3429 F02RECOMMENDED COMPONENT PLACEMENT. TRACES CARRYING HIGH CURRENT ARE DIRECT. TRACE AREA AT FB PIN IS SMALL. LEAD LENGTH TO BATTERY IS SHORTOUTPUT CURRENT (mA)Figure 2. Recommended Component Placementfor Single Layer BoardCOMPONENT SELECTIONInductor SelectionThe LTC3429/LTC3429B can utilize small surface mountand chip inductors due to its fast 500kHz switchingfrequency. Typically, a 4.7µH inductor is recommendedfor most applications. Larger values of inductance willallow greater output current capability by reducing the8
Uinductor ripple current. Increasing the inductance above10µH will increase size while providing little improvementin output current capability.The approximate output current capability of the LTC3429versus inductance value is given in the equation below andillustrated graphically in Figure 3.V•D⎞⎛IOUT(MAX)=η•⎜IP–IN⎟•(1–D)⎝f•L•2⎠where:η = estimated efficiencyIP = peak current limit value (0.6A)VIN = input (battery) voltageD = steady-state duty ratio = (VOUT – VIN)/VOUTf = switching frequency (500kHz typical)L = inductance value200180160140120100806040200357911131517192123INDUCTANCE (µH)3429 F03WUUVIN = 1.2VVOUT = 3.3VVOUT = 5VFigure 3. Maximum Output Current vsInductance Based on 90% Efficiency3429fa元器件交易网www.cecb2b.com
LTC3429/LTC3429BAPPLICATIO S I FOR ATIOThe inductor current ripple is typically set for 20% to 40%of the maximum inductor current (IP). High frequencyferrite core inductor materials reduce frequencydependent power losses compared to cheaper powderediron types, improving efficiency. The inductor should havelow ESR (series resistance of the windings) to reduce theI2R power losses, and must be able to handle the peakinductor current without saturating. Molded chokes andsome chip inductors usually do not have enough core tosupport the peak inductor currents of 850mA seen on theLTC3429/LTC3429B. To minimize radiated noise, use atoroid, pot core or shielded bobbin inductor. See Table 1for some suggested components and suppliers.Table 1. Recommended InductorsL(µH)4.1104.74.7104.73.34.7104.74.7104.7MAXDCRmΩ5712410517010918221617460759084137195HEIGHT(mm)2.02.01.81.83.53.50.80.82.92.92.92.02.02.2PARTCDRH5D18-4R1CDRH5D18-100CDRH3D16-4R7CDRH3D16-6R8CR43-4R7CR43-100CMD4D06-4R7MCCMD4D06-3R3MCDS1608-472DS1608-103DO1608C-472D52LC-4R7MD52LC-100MLQH32CN4R7M24VENDORSumidawww.sumida.comCoilcraftwww.coilcraft.comTokowww.tokoam.comMuratawww.murata.comUOutput and Input Capacitor SelectionLow ESR (equivalent series resistance) capacitors shouldbe used to minimize the output voltage ripple. Multilayerceramic capacitors are an excellent choice as they haveextremely low ESR and are available in small footprints. A4.7µF to 15µF output capacitor is sufficient for mostapplications. Larger values up to 22µF may be used toobtain extremely low output voltage ripple and improvetransient response. An additional phase lead capacitormay be required with output capacitors larger than 10µFto maintain acceptable phase margin. X5R and X7Rdielectric materials are preferred for their ability to main-tain capacitance over wide voltage and temperature ranges.Low ESR input capacitors reduce input switching noiseand reduce the peak current drawn from the battery. Itfollows that ceramic capacitors are also a good choice forinput decoupling and should be located as close as pos-sible to the device. A 10µF input capacitor is sufficient forvirtually any application. Larger values may be used with-out limitations. Table 2 shows a list of several ceramiccapacitor manufacturers. Consult the manufacturers di-rectly for detailed information on their entire selection ofceramic capacitors.Table 2. Capacitor Vendor InformationSUPPLIERAVXMurataTaiyo YudenWEBSITEwww.avxcorp.comwww.murata.comwww.t-yuden.com3429fa
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LTC3429/LTC3429BTYPICAL APPLICATIO SApplications Where VOUT > 4.3VWhen the output voltage is programmed above 4.3V, it isnecessary to add a Schottky diode either from SW to VOUT,or to add a snubber network in order to maintain anacceptable peak voltage on the SW pin. The Schottky diodebetween SW and VOUT will provide a peak efficiencyimprovement but will negate the output disconnect fea-ture. If output disconnect is required, an active snubbernetwork is suggested as shown below. Examples of Schot-tky diodes are: MBR0520L, PMEG2010EA, 1N5817 orequivalent.Application Circuit for VOUT > 4.3V Where Inrush Current Limiting and Output Disconnect are RequiredL14.7µHD1*100VIN2.7V TO 4.2V+Li-IonC14.7µF 6VIN OFFON4SHDNGND2FB3R2604kC210µFEFFICIENCY (%)LTC3429*LOCATE COMPONENTS CLOSE TO THE PINC1: TAIYO YUDEN X5R JMK212BJ475MMC2: TAIYO YUDEN X5R JMK212BJ106MMD1: MOTOROLA MBR0520LL1: COILCRAFT D0160C-472MP1: ZETEX ZXM61P02FApplication Circuit for VOUT > 4.3V Where Inrush Current Limiting and Output Disconnect are Not RequiredL14.7µHVIND1*+2 AACELLC14.7µF6VIN OFFON4SHDNGND2FB3R2604kC210µFEFFICIENCY (%)LTC3429*LOCATE COMPONENTS CLOSE TO THE PINC1: TAIYO YUDEN X5R JMK212BJ475MMC2: TAIYO YUDEN X5R JMK212BJ106MMD1: MOTOROLA MBR0520LL1: COILCRAFT D0160C-47210
ULi-Ion to 5V Efficiency100VIN = 4.2V90EFFICIENCY80706050400.1VIN = 3.6V101SWVOUT5R11.82MMP1VOUT5V250mAC3*0.22µFPOWER LOSS (W)10.1VIN = 4.2VPOWER LOSS0.01VIN = 3.6V3429 TA040.0010.000110003429 TA04b110100OUTPUT CURRENT (mA)2-Cell to 5V Efficiency100100VIN = 3VEFFICIENCYVIN = 2.4VVIN = 2.4VVIN = 3VPOWER LOSS50400.10.0010.000110003429 TA05b1SWVOUT5R11.82MVOUT5V150mA9080706010POWER LOSS (W)10.10.013429 TA05110100OUTPUT CURRENT (mA)3429fa元器件交易网www.cecb2b.com
LTC3429/LTC3429BPACKAGE DESCRIPTIOUS6 Package6-Lead Plastic TSOT-23(Reference LTC DWG # 05-08-1636)2.90 BSC(NOTE 4)1.22 REF1.4 MIN2.80 BSC1.50 – 1.75(NOTE 4)PIN ONE ID0.95 BSC0.30 – 0.45 6 PLCS (NOTE 3)0.80 – 0.900.20 BSC1.00 MAXDATUM ‘A’0.01 – 0.100.09 – 0.20(NOTE 3)1.90 BSCS6 TSOT-23 03020.62MAX0.95REF3.85 MAX2.62 REFRECOMMENDED SOLDER PAD LAYOUTPER IPC CALCULATOR0.30 – 0.50 REFNOTE:1. DIMENSIONS ARE IN MILLIMETERS2. DRAWING NOT TO SCALE3. DIMENSIONS ARE INCLUSIVE OF PLATING4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR5. MOLD FLASH SHALL NOT EXCEED 0.254mm6. JEDEC PACKAGE REFERENCE IS MO-1933429faInformation furnished by Linear Technology Corporation is believed to be accurate and reliable.However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.11
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LTC3429/LTC3429BTYPICAL APPLICATIOL14.7µHSingle AA Cell to 2.5V Synchronous Boost Converter+SINGLEAA CELLC14.7µF16SWVINVOUTLTC34295R11.02MR21.02MVOUT2.5V130mAC210µF OFFON4SHDNGND2FBC1: TAIYO YUDEN X5R JMK212BJ475MMC2: TAIYO YUDEN X5R JMK212BJ106MML1: COILCRAFT D0160C-472RELATED PARTSPART NUMBERLT1613LT1615/LT1615-1LT1618LTC1700LT1930/LT1930ALT1946/LT1946ALT1961LTC3400/LTC3400BLTC3401/LTC3402LTC3421LTC3425LT3464DESCRIPTION550mA (ISW), 1.4MHz High Efficiency Step-Up DC/DCConverter300mA/80mA (ISW), High Efficiency Step-UpDC/DC Converters1.5A (ISW), 1.25MHz High Efficiency Step-Up DC/DCConverterNo RSENSETM, 530kHz, Synchronous Step-Up DC/DCController1A (ISW), 1.2MHz/2.2MHz, High Efficiency Step-UpDC/DC Converters1.5A (ISW), 1.2MHz/2.7MHz, High Efficiency Step-UpDC/DC Converters1.5A (ISW), 1.25MHz High Efficiency Step-Up DC/DCConverter600mA (ISW), 1.2MHz, Synchronous Step-UpDC/DC Converters1A/2A (ISW), 3MHz, Synchronous Step-UpDC/DC Converters3A (ISW), 3MHz, Synchronous Step-Up DC/DCConverter with Output Disconnect5A (ISW), 8MHz, 4-Phase Synchronous Step-Up DC/DCConverter with Output Disconnect85mA (ISW), High Efficiency Step-Up DC/DC Converterwith Integrated Schottky and PNP DisconnectCOMMENTS90% Efficiency, VIN: 0.9V to 10V, VOUT(MAX) = 34V, IQ = 3mA, ISD < 1µA,ThinSOTVIN: 1V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD < 1µA, ThinSOT90% Efficiency, VIN: 1.6V to 18V, VOUT(MAX) = 35V, IQ = 1.8mA,ISD < 1µA95% Efficiency, VIN: 0.9V to 5V, IQ = 200µA, ISD < 10µA, MS10High Efficiency, VIN: 2.6V to 16V, VOUT(MAX) = 34V, IQ = 4.2mA/5.5mA,ISD < 1µA, ThinSOTHigh Efficiency, VIN: 2.45V to 16V, VOUT(MAX) = 34V, IQ = 32mA,ISD < 1µA, MS890% Efficiency, VIN: 3V to 25V, VOUT(MAX) = 35V, IQ = 0.9mA, ISD < 6µA,MS8E92% Efficiency, VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19µA/300µA,ISD < 1µA, ThinSOT97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V, IQ = 38µA, ISD < 1µA,MS1095% Efficiency, VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12µA,ISD < 1µA, QFN2495% Efficiency, VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12µA,ISD < 1µA, QFN32VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25µA, ISD < 1µA, ThinSOTNo RSENSE is a trademark of Linear Technology Corporation.12
Linear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.comUSingle AA Cell to 3.3VL14.7µHSINGLEAA CELL+C14.7µF16SWVINVOUTLTC34295R11.02MR2604kVOUT3.3V100mAC210µF3 OFFON4SHDNGND2FB33429 TA033429 TA06C1: TAIYO YUDEN X5R JMK212BJ475MMC2: TAIYO YUDEN X5R JMK212BJ106MML1: COILCRAFT D0160C-4723429fa LT/TP 1104 1K REV A • PRINTED IN USA
© LINEAR TECHNOLOGY CORPORATION 2004
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