LTC3539EDCB-PBF资料

LTC3539/LTC3539-22A, 1MHz/2MHz Synchronous Step-Up DC/DC Converters FEATURES

Delivers 3.3V at 900mA From 2 Alkaline/NiMH Cellsn Delivers 5V at 900mA From a Lithium-Polymer Batteryn V Start-Up Voltage: 700mVINn 1.5V to 5.25V VOUT Rangen Up to 94% Effi ciencyn V > VINOUT Operationn 1MHz (LTC3539) or 2MHz (LTC3539-2) Fixed Frequency Operationn Output Disconnectn Selectable Burst Mode® or PWM Operationn 10μA Quiescent Currentn Logic Controlled Shutdown: <1μAn Requires Only 6 External Componentsn Low Profi le (2mm × 3mm × 0.75mm) DFN PackagenDESCRIPTION

The LTC®3539/LTC3539-2 are synchronous, 2A step-up DC/DC converters with output disconnect. Synchronous rectifi cation enables high effi ciency in the low profi le 2mm × 3mm DFN package. Battery life is extended with a 700mV start-up voltage and operation down to 500mV once started.A switching frequency of 1MHz (LTC3539) or 2MHz (LTC3539-2) minimizes solution footprint by allowing the use of tiny, low profi le inductors and ceramic capacitors. The current mode PWM design is internally compensated, reducing external parts count. The LTC3539/LTC3539-2 feature a pin-enabled automatic Burst Mode operation at light load conditions. Anti-ring circuitry reduces EMI by damping the inductor in discontinuous mode. Additional features include a low shutdown current of under 1μA and thermal overload protection.The LTC3539/LTC3539-2 are offered in a 2mm × 3mm × 0.75mm DFN package.L, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.APPLICATIONS

Medical Instrumentsn Portable Bar Code Scannersn Noise Canceling Headphonesn Portable GPS Navigationn Handheld PCsnTYPICAL APPLICATION

Wide VIN, High Power 3.3V Regulator4.7μHVIN1.8V TO 3.6V100

2.2μFVINLTC3539PWMBURSTMODEVOUT1MOFFONSHDNGNDFBPGND562k3539 TA01aEffi ciency and Power Loss vs Load Current1000

EFFICIENCY100

POWER LOSS (mW)90

SWVOUT3.3V600mA22μFEFFICIENCY (%)807060

V = 2.4V50VIN = 3.3VOUT4030201000.1

1

22pF10

POWER LOSS1

FREQUENCY = 1MHzFREQUENCY = 2MHz10100

ILOAD AVERAGE (mA)

0.11000

3539 TA01b

3539f1

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LTC3539/LTC3539-2ABSOLUTE MAXIMUM RATINGS

(Note 1)PIN CONFIGURATION

TOP VIEW

SW1PGND2GND3VIN4

9

8VOUT7MODE6FB5SHDN

VIN Voltage ...................................................–0.3V to 6VSW VoltageDC ............................................................–0.3V to 6VPulsed <100ns .........................................–0.3V to 7VSHDN, FB, MODE Voltage ............................–0.3V to 6VVOUT .............................................................–0.3V to 6VOperating Temperature (Notes 2, 5) .........–40°C to 85°CStorage Temperature Range ...................–65°C to 125°CDCB PACKAGE

8-LEAD (2mm s 3mm) PLASTIC DFN

TJMAX = 125°C, θJA = 60°C/W TO 85°C/W (NOTE 6)EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCBORDER INFORMATION

LEAD FREE FINISHLTC3539EDCB#PBFLTC3539EDCB-2#PBFTAPE AND REELLTC3539EDCB#TRPBFLTC3539EDCB-2#TRPBFPART MARKINGLDCSLDPHPACKAGE DESCRIPTION8-Lead (2mm × 3mm) Plastic DFN8-Lead (2mm × 3mm) Plastic DFNTEMPERATURE RANGE–40°C to 85°C–40°C to 85°CConsult LTC Marketing for parts specifi ed with wider operating temperature ranges.Consult LTC Marketing for information on non-standard lead based fi nish parts.For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/E LECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the specifi ed PARAMETERInput Voltage RangeMinimum Start-Up VoltageOutput Voltage Adjust RangeFeedback VoltageFeedback Input CurrentQuiescent Current - ShutdownQuiescent Current - ActiveQuiescent Current - BurstN-Channel MOSFET Switch Leakage CurrentP-Channel MOSFET Switch Leakage CurrentN-Channel MOSFET Switch On ResistanceP-Channel MOSFET Switch On ResistanceN-Channel MOSFET Current LimitVFB = 1.2VVSHDN = 0V, Not Including Switch Leakage, VOUT = 0VMeasured on VOUT, Non-SwitchingMeasured on VOUT, FB >1.230VVSW = 5VVSW = 5V, VOUT = 0VVOUT = 3.3VVOUT = 3.3Vltemperature range of –40°C to 85°C, otherwise specifi cations are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, unless otherwise noted.CONDITIONSAfter Start-UpILOAD = 1mA, VOUT = 0VllMIN0.5TYP0.7MAX50.885.251.230501500181020UNITSVVVVnAμAμAμAμAμAΩΩA1.51.1701.20010.01300100.10.10.090.12522.63539f2

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LTC3539/LTC3539-2E LECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the specifi ed PARAMETERMaximum Duty CycleMinimum Duty CycleSwitching Frequency MODE Input High VoltageMODE Input Low VoltageMODE Input CurrentSHDN Input High VoltageSHDN Input Low VoltageSHDN Input CurrentVSHDN = 1.2VVSHDN = 3.3V0.31VMODE = 1.2V0.880.3120.3CONDITIONSVFB = 1.15VVFB = 1.3VLTC3539LTC3539-2lllltemperature range of –40°C to 85°C, otherwise specifi cations are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V, unless otherwise noted.MIN870.71.80.880.31TYP900121.32.4MAXUNITS%%MHzMHzVVμAVVμAμANote 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime.Note 2: The LTC3539E/LTC3539E-2 is guaranteed to meet performance specifi cations from 0°C to 85°C. Specifi cations over –40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls.Note 3: Specifi cation is guaranteed by design and not 100% tested in production.Note 4: Current measurements are made when the output is not switching.Note 5: This IC includes overtemperature protection that is intended to protect the device during momentary overload conditions. Junction temperature will exceed 125°C when overtemperature protection is active. Continuous operation above the specifi ed maximum operating junction temperature may result in device degradation or failure.Note 6: Failure to solder the exposed backside of the package to the PC board ground plane will result in a thermal resistance much higher than 60°C/W.3539f3

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LTC3539/LTC3539-2TYPICAL PERFORMANCE CHARACTERISTICS

Effi ciency vs Load Current and VIN, VOUT = 1.8V1009080EFFICIENCY (%)7060504030201000.1

1

VIN = 1VVIN = 1.2VVIN = 1.5V10100

LOAD CURRENT (mA)

0.1

POWER LOSSEFFICIENCY10100

POWER LOSS (mW)EFFICIENCY (%)1000

10090807060504030201000.1

1

POWER LOSS1

VIN = 1.2VVIN = 1.8VVIN = 3V10100

LOAD CURRENT (mA)

10

EFFICIENCY100

POWER LOSS (mW) (TA = 25°C unless otherwise noted)Effi ciency vs Load Current and VIN, VOUT = 3.3V1000

1

0.0110000.11000

3539 G013539 G02

Effi ciency vs Load Current and VIN, VOUT = 5V1009080EFFICIENCY (%)7060504030201000.1

1

VIN = 2.4VVIN = 3.6VVIN = 4.2V10100

LOAD CURRENT (mA)

POWER LOSS110

EFFICIENCY100

POWER LOSS (mW)1000

100908070

No Load Input Current vs VINVOUT = 1.8VVOUT = 2.5VVOUT = 3.3VVOUT = 5VIOUT (mA)200018001600140012001000800600400200

1.0

1.5

2.0

2.53.0VIN (V)

3.5

4.0

4.5

3539 G04

Maximum Output Current vs VINIIN (μA)60504030201000.5

0.11000

3539 G03

0

0.51.01.52.02.53.03.54.04.55.0

VIN (V)

3539 G05

VOUT = 1.8VVOUT = 2.5VVOUT = 3.3VVOUT = 5VMinimum Load Resistance During Start-Up vs VIN10000

VOUT = 3.3V6050OUTPUT CURRENT (mA)LOAD RESISTANCE (Ω)1000

40302010

0.10.65

0

Burst Mode Threshold Current vs VIN and VOUT1.10NORMALIZED CURRENT LIMIT (A)1.051.000.950.900.85

Normalized Current Limit vs VOUT100

10

VOUT = 1.8VVOUT = 2.5VVOUT = 3.3VVOUT = 5V0

0.51.01.52.02.53.03.54.04.5

INPUT VOLTAGE (V)

3539 G11

0.750.85

0.95VIN (V)

1.051.15

3539 G06

0.80

1.0

1.52.0

2.53.03.5VOUT (V)

4.04.55.0

3539 G16

3539f4

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LTC3539/LTC3539-2TYPICAL PERFORMANCE CHARACTERISTICS

RDS(ON) vs VOUT0.300.25

NORMALIZED RDS(ON) (Ω)0.20RDS(ON) (Ω)0.150.10

NMOS0.0501.5

1.31.21.11.00.90.80.7–50

CHANGE IN VFB (%)RDS(ON) Change vs Temperature0.500.250–0.25–0.50–0.75

VFB vs TemperaturePMOS2.02.5

3.03.54.0VOUT (V)

4.55.05.5

3539 G07

–30

–10103050TEMPERATURE (°C)

7090

3539 G08

–1.00

–60–40–200204060

TEMPERATURE (°C)

80100

3539 G09

Start-Up Voltage vs Temperature0.800.75

1mA LOAD0.70VIN (V)0.65

NO LOAD0.600.550.50

–50

SW PIN2V/DIV VOUT20mV/DIVAC-COUPLED INDUCTORCURRENT500mA/DIV

Fixed Frequency SW and IL(AC)SW PIN5V/DIV VOUT20mV/DIVAC-COUPLED INDUCTORCURRENT200mA/DIV

Burst Mode SW and IL(AC)500ns/DIV

VIN = 2.4V

VOUT = 3.3V AT 400mACOUT = 22μF

3539 G12

5μs/DIV

VIN = 3.3VVOUT = 5VCOUT = 22μF

3539 G13

–25

02550TEMPERATURE (°C)

75100

3539 G10

Load Step, Fixed FrequencyLoad Step, Burst Mode Operation VOUT50mV/DIVAC-COUPLED LOADCURRENT200mA/DIV

500μs/DIV

VIN = 2.4VVOUT = 3.3VCOUT = 22μF

ILOAD = 100mA TO 250mA STEP

3539 G14

VOUT50mV/DIVAC-COUPLED LOADCURRENT200mA/DIV

500μs/DIV

VIN = 2.4VVOUT = 3.3VCOUT = 22μF

ILOAD = 20mA TO 170mA

3539 G15

3539f5

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LTC3539/LTC3539-2PIN FUNCTIONS

SW (Pin 1): Switch Pin. Connect inductor between SW and VIN. Keep PCB trace lengths as short and wide as pos-sible to reduce EMI. If the inductor current falls to zero, or SHDN is low, an internal anti-ring resistor is connected from SW to VIN to minimize EMI.PGND (Pin 2), GND (Pin 3): Signal and Power Ground. Provide a short direct PCB path between PGND, GND and the (–) side of the input and output capacitors.VIN (Pin 4): Battery Input Voltage. Connect a minimum of 2.2μF ceramic decoupling capacitor from this pin to ground.SHDN (Pin 5): Logic Controlled Shutdown Input. There is an internal 4MΩ pull-down on this pin. SHDN = High: Normal operation. SHDN = Low: Shutdown, quiescent current <1μA. er. Con-FB (Pin 6): Feedback Input to the gm Error Amplifinect resistor divider tap to this pin. The output voltage can be adjusted from 1.5V to 5.25V by: VOUT = 1.20V • [1 + (R2/R1)]MODE (Pin 7): Burst Mode Pin. A logic controlled input to select either automatic Burst Mode operation or forced fi xed frequency operation. MODE = High: Burst Mode operation at light loads MODE = Low: Fixed frequency PWM ModeVOUT (Pin 8): Output Voltage Sense and Drain of the Internal Synchronous Rectifi er. PCB trace length from lter capacitor should be as short and VOUT to the output fiwide as possible.Exposed Pad (Pin 9): The exposed pad must be soldered to the PCB ground plane. It serves as another ground connection, and as a means of conducting heat away from the die.BLOCK DIAGRAM

VIN1VOUTVSELVBESTVBSW4VINWELLSWITCH8VOUTR26FBR1VOUTOFFON5SHDNSHUTDOWNSHUTDOWNGATE DRIVERSANDANTI-CROSSCONDUCTIONIPKCOMPARATOR–+IZEROCOMPARATOR3+–CLAMPSOFT-STARTSLOPECOMPARATORVREFFBVREFUVLOVREFUVLOIPKSTART-UP1MHz/2MHzOSCPWMBURST

7MODETHERMALSHUTDOWNTSDCLKLOGIC ANDBURST MODECONTROLIZEROBURSTWAKE9EXPOSED PAD2PGND3GND3539 BD6

–+ERRORAMPLIFIER/SLEEPCOMPARATOR3539f元器件交易网www.cecb2b.com

LTC3539/LTC3539-2OPERATION

DETAILED DESCRIPTIONThe LTC3539 is a high power synchronous boost converter in an 8-lead 2mm × 3mm DFN package. With the ability to start up and operate from inputs of 700mV, the device features fi xed frequency, current mode PWM control for exceptional line and load regulation. The current mode architecture with adaptive slope compensation provides excellent transient load response, requiring minimal output fi ltering. Internal soft-start and internal loop compensa-tion simplifi es the design process while minimizing the number of external components. The switching frequency of the LTC3539 is nominally 1MHz, while the LTC3539-2 switches at 2MHz. Operation of the LTC3539 and LTC3539-2 is identical in all other respects.With its low RDS(ON) and low gate charge internal N-chan-nel MOSFET switch and P-channel MOSFET synchronous rectifi er, the LTC3539 achieves high effi ciency over a wide range of load current. Burst Mode operation maintains high effi ciency at very light loads, reducing the quiescent current to just 10μA.Converter operation can be best understood by referring to the Block Diagram.Low Voltage Start-UpThe LTC3539 includes an independent start-up oscillator designed to start up at an input voltage of 0.7V (typical). Soft-start and inrush current limiting are provided during start-up, as well as normal mode.When either VIN or VOUT exceeds 1.4V typical, the IC enters normal operating mode. Once the output voltage exceeds the input by 0.24V, the IC powers itself from VOUT instead of VIN. At this point the internal circuitry has no dependency on the VIN input voltage, eliminating the requirement for a large input capacitor. The input voltage can drop as low as 0.5V. The limiting factor for the appli-cation becomes the ability of the power source to supply suffi cient energy to the output at the low voltages, and the maximum duty cycle, which is clamped at 90% typical. Note that at low input voltages, small voltage drops due to series resistance become critical, and greatly limit the power delivery capability of the converter.Low Noise Fixed Frequency OperationSoft-Start: The LTC3539/LTC3539-2 contains internal circuitry to provide soft-start operation. The internal soft-start circuitry ramps the peak inductor current from zero to its peak value of 2.6A (typical) in approximately 0.5ms, allowing start-up into heavy loads. The soft-start circuitry is reset in the event of a thermal shutdown or shutdown command.Oscillator: An internal oscillator sets the switching frequency to 1MHz for the LTC3539, and 2MHz for the LTC3539-2.Shutdown: The part is shutdown by pulling the SHDN pin below 0.3V, and activated by pulling the SHDN pin above 0.88V. Note that SHDN can be driven above VIN or VOUT, as long as it is limited to less than the absolute maximum rating.Error Amplifi er: The error amplifi er is a transconductance type. The non-inverting input is internally connected to the 1.2V reference and the inverting input is connected to FB. Clamps limit the minimum and maximum error amp output voltage for improved large signal transient response. Power converter control loop compensation is provided internally. A voltage divider from VOUT to ground programs the output voltage via FB from 1.5V to 5.25V. VOUT = 1.2V • [1 + (R2/R1)].Current Sensing: Lossless current sensing converts the peak current signal of the N-channel MOSFET switch into a voltage which is summed with the internal slope compensation. The summed signal is compared to the error amplifi er output to provide a peak current control command for the PWM.Current Limit: The current limit comparator shuts off the N-channel MOSFET switch once its threshold is reached. Peak switch current is limited to approximately 2.6A, independent of input or output voltage, unless VOUT falls below 0.7V, in which case the current limit is cut in half.3539f7

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LTC3539/LTC3539-2OPERATION

Zero Current Comparator: The zero current comparator monitors the inductor current to the output and shuts off the synchronous rectifi er once this current reduces to ap-proximately 40mA. This prevents the inductor current from reversing in polarity, improving effi ciency at light loads.Synchronous Rectifi er: The P-channel MOSFET synchro-nous rectifi er is disabled when VOUT is much less than VIN. This is to control inrush current and to prevent inductor current from running awayAnti-ringing Control: The anti-ringing control connects a resistor across the inductor to prevent high frequency ringing on the SW pin during discontinuous current mode operation. The ringing of the resonant circuit formed by L and CSW (capacitance on SW pin) is low energy, but can cause EMI radiation.Output Disconnect: The LTC3539 is designed to allow true output disconnect by eliminating body diode conduction of the internal P-channel MOSFET rectifi er. This allows VOUT to go to zero volts during shutdown, drawing no current from the input source. It also provides inrush current limiting at turn-on, minimizing surge currents seen by the input supply. Note that to obtain the advantages of output disconnect, there must not be an external Schottky diode connected between the SW pin and VOUT. The output disconnect feature also allows VOUT to be pulled high, without any reverse current into a battery on VIN.Thermal Shutdown: If the die temperature exceeds 160°C, the device will go into thermal shutdown. All switches will be turned off and the internal soft-start capacitor will be discharged. The device will be enabled again when the die temperature drops by about 15°C.Burst Mode OperationWhen Burst Mode operation is enabled by bringing the MODE pin above 0.88V, the LTC3539 will automatically enter Burst Mode operation at light load current, then return to fi xed frequency PWM mode when the load in-creases. Refer to the typical performance characteristics to see the output load Burst Mode threshold vs VIN. The load current at which Burst Mode operation is entered can be changed by adjusting the inductor value. Raising the inductor value will lower the load current at which Burst Mode operation is entered.In Burst Mode operation, the LTC3539 still switches at a fi xed frequency, using the same error amplifi er and loop compensation for peak current mode control. This control method eliminates any output transient when switching between modes. In Burst Mode operation, energy is deliv-ered to the output until it reaches the nominal regulation value, then the LTC3539 transitions to Sleep mode where the outputs are off and the LTC3539 consumes only 10μA of quiescent current from VOUT. When the output voltage droops slightly, switching resumes. This maximizes ef-fi ciency at very light loads by minimizing switching and quiescent current losses. Burst Mode output voltage ripple, which is typically 1% peak to peak, can be reduced by using more output capacitance (47μF or greater).As the load increases, the LTC3539 will automatically leave Burst Mode operation. Once the LTC3539 has left Burst Mode operation and returned to normal operation, it will remain there until the output load is reduced below the burst threshold.Burst Mode operation is inhibited during start-up until soft-start is complete and VOUT is at least 0.24V greater than VIN.When the MODE pin is below 0.3V, the LTC3539 features continuous PWM operation. In this mode, at very light loads, the LTC3539 will exhibit pulse-skip operation. If the MODE pin voltage exceeds the greater of VIN or VOUT by 0.5V, the MODE pin will sink additional current.3539f8

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LTC3539/LTC3539-2APPLICATIONS INFORMATION

VIN > VOUT OperationThe LTC3539 will maintain output voltage regulation even when the input voltage is above the desired output. Note that the effi ciency and the maximum output current capability are reduced. Refer to Typical Performance Characteristics.Short-Circuit ProtectionThe LTC3539 output disconnect feature allows an output short circuit while maintaining a maximum internally set current limit. To reduce power dissipation under short-circuit conditions, the peak switch current limit is reduced to 1.4A (typical).Schottky DiodeAlthough it is not required, adding a Schottky diode from ciency by about 2%. Note that SW to VOUT will improve effithis defeats the output disconnect, VIN > VOUT operation and short circuit protection features.PCB LAYOUT GUIDELINESThe high speed operation of the LTC3539 demands careful attention to board layout. A careless layout will result in reduced performance. Figure 1 shows the recommended component placement. A large ground pin copper area will help to lower the die temperature. A multilayer board with a separate ground plane is ideal.COMPONENT SELECTIONInductor SelectionThe LTC3539 can utilize small surface mount and chip inductors due to the high switching frequency. Inductor values between 3.3μH and 4.7μH for the LTC3539 and between 1.5μH and 2.5μH for the LTC3539-2 are suitable for most applications*. Larger values of inductance will allow slightly greater output current capability (and lower the Burst Mode threshold) by reducing the inductor ripple current. However, increasing the inductance above 10μH will increase size while providing little improvement in output current capability.The minimum inductance value is given by:L> Where: f = 1 for the LTC3539 or 2.2 for the LTC3539-2Ripple = allowable inductor current ripple (Amps peak-to-peak)VIN(MIN) = minimum input voltageVOUT(MAX) = maximum output voltageThe inductor current ripple is typically set for 20% to 40% of the maximum inductor current. High frequency ferrite core inductor materials improve effi ciency by reducing frequency dependent power losses compared to cheaper powdered iron types. The inductor should have low ESR (series resistance of the windings) to reduce the I2R power losses, and must accomodate the peak inductor current without saturating. Molded chokes and some chip inductors usually do not have enough core area to support the peak inductor current of 2.6A seen on the LTC3539. To minimize radiated noise, use a shielded inductor. See Table 1 for suggested suppliers and representative components.*Single cell applications (VIN < 1.6V) should use a 2.2μH inductor for the LTC3539MULTIPLE VIASTO GROUND PLANE3539 F01VIN(MIN)•(VOUT(MAX)−VIN(MIN))

Ripple•VOUT(MAX)•f

LTC3539SW1PGND2GND3VIN48VOUT7MODE6FB5SHDNMINIMIZETRACE ON FBAND SW

VIN+Figure 1. Recommended Component Placement for Single Layer Board3539f9

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LTC3539/LTC3539-2APPLICATIONS INFORMATION

Table 1. Representative InductorsVENDORCoilcraft(847) 639-00www.coilcraft.comMuratawww.murata.comSumida(847) 956-0666www.sumida.comTDK(847) 803-6100www.component.tdk.comToko(408) 432-8282www.tokoam.comWurth(201) 785-8800www.we-online.comPART/STYLEMSS5131LPS4018-222MSS6132MOS6020LQH55DLQH66SCDRH4D22CDRH4D28CCDRH5D28CDR6D23VLF5014STAn output capacitor of up to 100μF is required at lower output voltages. Even with VOUT greater than 3V, larger values up to 100μF may be used to obtain extremely low output voltage ripple and improve transient response. X5R and X7R dielectric materials are preferred for their ability to maintain capacitance over wide voltage and temperature ranges. Y5V types should not be used.A small ceramic capacitor in parallel with a larger tantalum capacitor may be used in demanding applications which have large load transients. A feedforward capacitor across the top resistor of the feedback divider (from VOUT to FB) is usually required to improve transient response. A typical value of 22pF will generally suffi ce.Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. It follows that ceramic capacitors are also a good choice for input decoupling and should be located as close as possible to the device. A 2.2μF input capacitor is suffi cient for most applications. Larger values may be used without limita-tions. Table 2 shows a list of several ceramic capacitor manufacturers. Consult the manufacturers directly for detailed information on their selection of ceramic parts.Table 2. Capacitor Vendor InformationSUPPLIERAVXMurataTaiyo-YudenTDKPHONE(803) 448-9411(714) 852-2001(408) 573-4150(847) 803-6100WEBSITEwww.avxcorp.comwww.murata.comwww.t-yuden.comwww.component.tdk.comD53LCD63LCBWE-TPC Type LH, XWE-PD Type XSOutput and Input Capacitor SelectionThe internal loop compensation of the LTC3539 is designed to be stable with output capacitor values of 10μF or greater. Although ceramic capacitors are recommended, low ESR (equivalent series resistance) tantalum capacitors may be used as well.Low ESR capacitors should be used to minimize the output voltage ripple. Multilayer ceramic capacitors are an excellent choice as they have extremely low ESR and are available in small footprints. A 22μF to 47μF output capacitor is suffi cient for output voltages of 3V or greater. TYPICAL APPLICATIONS

1 Cell to 1.8V2.2μHVIN1V TO 1.6V2.2μFVINSWVOUT1.8V500mA22μF*x5VIN0.9V TO 1.6V2.2μFVINSWVOUT3.3V350mA22μFx21 Cell to 3.3V2.2μHVIN3V TO 4.5V2.2μFLi-Ion Cell to 5V2.2μHVINSWVOUT5V750mA22μF309k3539 TA04LTC3539PWMBURSTMODEVOUT1MOFFONSHDNFB1.91M3539 TA02LTC3539PWMBURSTMODEVOUT1MOFFONSHDNFB562k3539 TA03LTC3539-2PWMBURSTMODEVOUT1MOFFONSHDNFB22pF22pF22pFGNDPGND*AT HIGH LOAD CURRENTS, ATANTALUM CAPACITOR WILLIMPROVE PERFORMANCE.GNDPGNDGNDPGND3539f10

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LTC3539/LTC3539-2PACKAGE DESCRIPTION

DCB Package8-Lead Plastic DFN (2mm × 3mm)(Reference LTC DWG # 05-08-1718 Rev A)0.70 ±0.053.50 ±0.052.10 ±0.051.35 ±0.051.65 ± 0.05PACKAGEOUTLINE0.25 ± 0.050.45 BSC1.35 REFRECOMMENDED SOLDER PAD PITCH AND DIMENSIONSAPPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED

R = 0.115TYPR = 0.055TYP2.00 ±0.10(2 SIDES)0.40 ± 0.1081.35 ±0.103.00 ±0.10(2 SIDES)PIN 1 BARTOP MARK(SEE NOTE 6)40.200 REF0.75 ±0.051.35 REF0.00 – 0.05BOTTOM VIEW—EXPOSED PAD

10.23 ± 0.050.45 BSC1.65 ± 0.10PIN 1 NOTCHR = 0.20 OR 0.25 × 45° CHAMFER

(DCB8) DFN 0106 REV ANOTE:

1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE2. DRAWING NOT TO SCALE

3. ALL DIMENSIONS ARE IN MILLIMETERS

4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE

MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE5. EXPOSED PAD SHALL BE SOLDER PLATED

6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE

3539fInformation 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 representa-tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.11

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LTC3539/LTC3539-2RELATED PARTS

PART NUMBERDESCRIPTIONLTC3400/LTC3400BLTC3401LTC3402LTC3421LTC3422LTC3423/LTC3424600mA ISW, 1.2MHz, Synchronous Step-Up DC/DC ConvertersCOMMENTS92% Effi ciency VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19μA/300μA, ISD <1μA, ThinSOT™ Package1A ISW, 3MHz, Synchronous Step-Up DC/DC Converter 97% Effi ciency VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD <1μA, 10-Lead MS Package2A ISW, 3MHz, Synchronous Step-Up DC/DC Converter 97% Effi ciency VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD <1μA, 10-Lead MS Package3A ISW, 3MHz, Synchronous Step-Up DC/DC Converter 95% Effi ciency VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12μA, ISD <1μA, with Output DisconnectQFN24 Package1.5A ISW, 3MHz Synchronous Step-Up DC/DC Converter with Output Disconnect1A/2A ISW, 3MHz, Synchronous Step-Up DC/DC Converter95% Effi ciency VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 25μA, ISD <1μA, 3mm × 3mm DFN Package95% Effi ciency VIN: 0.5V to 5.5V, VOUT(MAX) = 5.5V, IQ = 38μA, ISD <1μA, 10-Lead MS Package92% Effi ciency VIN: 1.6V to 4.3V, VOUT(MAX) = 5V, ISD <1μA, SOT-23 Package92% Effi ciency VIN: 1.8V to 5V, VOUT(MAX) = 5.25V, ISD <1μA, 3mm × 3mm DFN Package96% Effi ciency VIN: 0.5V to 4.4V, VOUT(MAX) = 5V, IQ = 20μA/300μA,93% Effi ciency VIN: 1.5V to 6V, VOUT(MAX) = 7.5V, IQ = 15μA, ISD <1μA, DFN12 Package94% Effi ciency VOUT(MAX) = 6V, IQ = 12μA, DFN12 PackageLTC3426 2A ISW, 1.2MHz, Step-Up DC/DC Converter LTC3428 500mA ISW, 1.25MHz/2.5MHz, Synchronous Step-Up DC/DC Converters with Output DisconnectLTC3429 600mA ISW, 500kHz, Synchronous Step-Up DC/DC Converter with Output Disconnect and Soft-Start LTC3458LTC3458L1.4A ISW, 1.5MHz, Synchronous Step-Up DC/DC Converter/Output Disconnect/Burst Mode Operation1.7A ISW, 1.5MHz, Synchronous Step-Up DC/DC Converter with Output Disconnect, Automatic Burst Mode Operation70mA ISW, 10V Micropower Synchronous Boost Converter/Output Disconnect/Burst Mode Operation400mA Micropower Synchronous Step-Up DC/DC Converter with Output Disconnect400mA Micropower Synchronous Step-Up DC/DC Converter with Output DisconnectLTC3459LTC3525-3/LTC3525-3.3/LTC3525-5LTC3525L-3LTC3526/LTC3526BLTC3526LLTC3527/LTC3527-1LTC3528/ LTC3528BVIN: 1.5V to 5.5V, VOUT(MAX) = 10V, IQ = 10μA, ISD <1μA, ThinSOT Package95% Effi ciency VIN: 1V to 4.5V, VOUT(MAX) = 3.3V or 5V, IQ = 7μA, ISD <1μA, SC-70 Package95% Effi ciency VIN: 0.88V to 4.5V, VOUT(MAX) = 3V, IQ = 7μA, ISD <1μA, SC-70 Package500mA, 1MHz Synchronous Step-Up DC/DC Converter 94% Effi ciency VIN: 0.85V to 5V, VOUT(MAX) = 5.25V, IQ = 9μA, ISD <1μA, 2mm × 2mm DFN-6 Packagewith Output Disconnect550mA, 1MHz Synchronous Step-Up DC/DC Converter 94% Effi ciency VIN: 0.68V to 5V, VOUT(MAX) = 5.25V, IQ = 9μA, ISD <1μA, with Output Disconnect2mm × 2mm DFN-6 PackageDual 800mA/400mA, 1.2MHz/2.2MHz Synchronous Step-Up DC/DC Converter with Output Disconnect94% Effi ciency VIN: 0.68V to 5V, VOUT(MAX) = 5.25V, IQ = 12μA, ISD <1μA, 3mm × 3mm QFN-16 Package1A, 1MHz Synchronous Step-Up DC/DC Converter with 94% Effi ciency VIN: 0.68V to 5V, VOUT(MAX) = 5.25V, IQ = 12μA, ISD <1μA, 2mm × 3mm DFN-8 PackageOutput DisconnectThinSOT is a trademark of Linear Technology Corporation.3539f12

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