LTC3526EDC-2#PBF资料

LTC3526-2/LTC3526B-2500mA 2MHz Synchronous Step-Up DC/DC Converters in 2mm × 2mm DFNFEATURES

Delivers 3.3V at 100mA from a Single Alkaline/NiMH Cell or 3.3V at 200mA from Two Cellsn V Start-Up Voltage: 850mVINn V Operating Range: 0.5V to 5VINn 1.6V to 5.25V VOUT Rangen Up to 94% Effi ciencyn Output Disconnectn 2MHz Fixed Frequency Operationn V > VINOUT Operationn Integrated Soft-Startn Current Mode Control with Internal Compensationn Burst Mode® Operation with 9μA Quiescent Current (LTC3526-2)n Low Noise PWM Operation (LTC3526B-2)n Internal Synchronous Rectifi ern Logic Controlled Shutdown (I < 1μA)Qn Anti-Ringing Controln Low Profi le (2mm × 2mm × 0.75mm) DFN-6 PackagenDESCRIPTION

The LTC®3526-2/LTC3526B-2 are synchronous, fi xed frequency step-up DC/DC converters with output discon-nect. Synchronous rectifi cation enables high effi ciency in the low profi le 2mm × 2mm DFN package. Battery life in single AA/AAA powered products is extended further with an 850mV start-up voltage and operation down to 500mV once started.A switching frequency of 2MHz minimizes solution foot-print 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 LTC3526-2 features Burst Mode operation at light load conditions, while the LTC3526B-2 features continuous switching. Anti-ring circuitry eliminates EMI concerns by damping the inductor in discontinuous mode. Additional features include a low shutdown current of under 1μA and thermal shutdown.The LTC3526-2/LTC3526B-2 are housed in a 6-pin 2mm × 2mm × 0.75mm DFN package.L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. Burst Mode is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. Patents pending.APPLICATIONS

Medical Instrumentsn Flash-Based MP3 Playersn Noise Canceling Headphonesn Wireless Micen Bluetooth HeadsetsnTYPICAL APPLICATION

2.2μHVIN1.6V TO 3.2V1μFOFF ONSWVINVOUT1.78M4.7μF

1M35262b2fA01aLTC3526-2 Effi ciency and Power Loss vs Load Current1009080EFFICIENCY (%)VIN = 2.4VEFFICIENCY100

POWER LOSS (mW)1000

LTC3526-2SHDNGNDFBVOUT

3.3V200mA7060504030201000.01

0.1

1

10

100

0.011000

35262b2f TA01b

10

POWER LOSS1

0.1

LOAD CURRENT (mA)

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LTC3526-2/LTC3526B-2ABSOLUTE MAXIMUM RATINGS

(Note 1)PIN CONFIGURATION

TOP VIEW

SW1GND2VIN3

7

6VOUT5FB4SHDN

VIN Voltage ...................................................–0.3V to 6VSW Voltage DC ............................................................–0.3V to 6V Pulsed <100ns .........................................–0.3V to 7VSHDN, 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°CDC PACKAGE

6-LEAD (2mm × 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 60°C/W (NOTE 6)EXPOSED PAD (PIN 7) IS GND, MUST BE SOLDERED TO PC BOARDORDER INFORMATION

LEAD FREE FINISHLTC3526EDC-2#PBFLTC3526BEDC-2#PBFTAPE AND REELLTC3526EDC-2#TRPBFLTC3526BEDC-2#TRPBFPART MARKINGLCNMLCNPPACKAGE DESCRIPTION6-Lead (2mm × 2mm) Plastic DFN6-Lead (2mm × 2mm) 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/l denotes the specifi cations which apply over the specifi ed operating The temperature range of –40°C to 85°C, otherwise specifi cations are at TA = 25°C. VIN = 1.2V, VOUT = 3.3V unless otherwise noted.ELECTRICAL CHARACTERISTICS

ILOAD = 1mA0°C to 85°CPARAMETERMinimum Start-Up Input VoltageOutput Voltage Adjust RangeFeedback Pin VoltageFeedback Pin Input Current Quiescent 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 LimitCurrent Limit Delay to OutputMaximum Duty CycleMinimum Duty CycleSwitching FrequencySHDN Pin Input High VoltageSHDN Pin Input Low VoltageSHDN Pin Input CurrentCONDITIONSllMIN1.71.61.165TYP0.85MAX15.255.25UNITSVVVVnAμAμAμAμAμAΩΩmAns%1.19510.0125090.10.10.40.61.22550150018510VFB = 1.30VVSHDN = 0V, Not Including Switch Leakage, VOUT = 0VMeasured on VOUT, NonswitchingMeasured on VOUT, FB > 1.230V (LTC3526-2 Only)VSW = 5VVSW = 5V, VOUT = 0VVOUT = 3.3VVOUT = 3.3Vl500851.80.97006090022.40.3(Note 3)VFB = 1.15V, VOUT = 5VVFB = 1.3Vlll%MHzVVμAμA35262b2faVSHDN = 1.2VVSHDN = 3.3V0.31122元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2ELECTRICAL CHARACTERISTICS

Note 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 LTC3526E-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.TYPICAL PERFORMANCE CHARACTERISTICS

Effi ciency vs Load Current and VIN for VOUT = 1.8V (LTC3526-2)1009080EFFICIENCY (%)7060504030201000.01

0.1

PLOSS AT VIN = 1.0VPLOSS AT VIN = 1.2VPLOSS AT VIN = 1.5V110100LOAD CURRENT (mA)

0.11

VIN = 1.0VVIN = 1.2VVIN = 1.5V100POWER LOSS (mW)EFFICIENCY (%)1000

10090807060504030201000.01

0.1

PLOSS AT VIN = 1.2V0.1

PLOSS AT VIN = 2.4VPLOSS AT VIN = 3.0V110100LOAD CURRENT (mA)

0.011000

1

VIN = 1.2VVIN = 2.4VVIN = 3.0V100POWER LOSS (mW)Effi ciency vs Load Current and VIN for VOUT = 3.3V (LTC3526-2)1000

100908070IIN (μA)6050403020

No-Load Input Current vs VINVOUT = 5VVOUT = 3.3VVOUT = 2.5VVOUT = 1.8V1010

0.011000

100.5

1.01.52.02.5VIN (V)

3.03.54.04.5

35262b2f G0135262b2f G0235262b2f G04

Effi ciency vs Load Current and VIN for VOUT = 5V (LTC3526-2)1009080EFFICIENCY (%)7060504030201000.01

10

VIN = 1.2VVIN = 2.4VVIN = 3.6V1VIN = 4.2V100POWER LOSS (mW)1000

400350300IOUT (mA)25020015010050

Maximum Output Current vs VIN VOUT = 3.3VVOUT = 2.5VVOUT = 1.8VLOAD (Ω)1000

Minimum Load Resistance During Start-Up vs VINVOUT = 5V100

PLOSS AT VIN = 1.2V0.1

PLOSS AT VIN = 2.4VPLOSS AT VIN = 3.6VPLOSS AT VIN = 4.2V0.01

0.11101001000

LOAD CURRENT (mA)

35262b2f

00.5

L = 2.2μH1.0

1.5

2.0

2.5VIN (V)

35262b2f G05

3.03.54.04.5

100.85

0.95

1.05VIN (V)

1.151.25

35262b2f

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LTC3526-2/LTC3526B-2TYPICAL PERFORMANCE CHARACTERISTICS

Start-Up Delay Time vs VIN100908070DELAY (μs)60504030201001.0

1.5

2.0

2.53.0

VIN (V)

3.5

4.0

4.5

01

1.25VIN (V)

1.5

35262b2f G08a

Burst Mode Threshold Current vs VIN 3025LOAD CURRENT (mA)2015105

LEAVE BURSTENTER BURSTVOUT = 1.8VCOUT = 10μFL = 2.2μHLOAD CURRENT (mA)40

Burst Mode Threshold Current vs VIN VOUT = 2.5V35COUT = 10μFL = 2.2μH3025

LEAVE BURST201510501

1.25

VIN (V)

35262b2f

ENTER BURST1.51.75

35262b2f

Burst Mode Threshold Current vs VIN 50

VOUT = 3.3V45COUT = 10μFL = 2.2μH40

LOAD CURRENT (mA)LEAVE BURST6050403020

Burst Mode Threshold Current vs VIN VOUT = 5VCOUT = 10μFL = 2.2μHFREQUENCY CHANGE (%)210–1–2–3–4–5

1.5

2.0

2.53.0VIN (V)

3.5

4.0

4.5

Oscillator Frequency Change vs VOUTNORMALIZED TO 3.3VLOAD CURRENT (mA)353025201510501.0

LEAVE BURSTENTER BURST1001.0

ENTER BURST1.5

2.0VIN (V)

2.53.0

35262b2f

–61.5

2.02.5

3.03.5VOUT (V)

4.04.55.0

35262b2f G08d35262b2f

RDS(ON) vs VOUT0.900.850.800.750.70RDS(ON) (Ω)0.650.600.550.500.450.400.350.30

1.5

2.0

2.5

3.03.5VOUT (V)

4.0

4.5

5.0

NMOSPMOSFREQUENCY CHANGE (%)10820–2–4–6–8

Oscillator Frequency Changevs TemperatureNORMALIZED TO 25˚C1.31.2NORMALIZED RDS(ON)1.11.00.90.8

RDS(ON) Change vs TemperatureNORMALIZED TO 25˚C–10–50

–30

–10103050TEMPERATURE (˚C)

7090

0.7–50

–30

–10103050TEMPERATURE (˚C)

7090

35262b2f

35262b2f G1135262b2f G12

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LTC3526-2/LTC3526B-2VFB vs Temperature0.500.25CHANGE IN VFB (%)0

VIN (V)–0.25–0.50–0.75

–1.00

204060–60–40–200

TEMPERATURE (˚C)

NORMALIZED TO 25˚C1.000.950.90

Start-Up Voltage vs TemperatureLOAD = 1mA10.09.59.0IQ (μA)8.58.07.57.01.5

Burst Mode Quiescent Currentvs VOUT0.850.800.750.70

–50

80100–30

–101030–50TEMPERATURE (°C)

70902.02.5

3.03.5VOUT (V)

4.04.55.0

35262b2f35262b2f G1435262b2f

Fixed Frequency Switching Waveform and VOUT RippleBurst Mode WaveformsVOUT1V/DIVINPUTCURRENT0.2A/DIVSHDN PIN1V/DIV

20μs/DIVVIN = 1.2V

VOUT = 3.3V AT 5mACOUT = 10μF

35262b2

VOUT and IIN During Soft-StartSW PIN2V/DIVVOUT10mV/DIVAC COUPLED

200ns/DIV

35262b2f

SW PIN2V/DIVVOUT50mV/DIVAC COUPLED

VIN = 1.2V

VOUT = 3.3V AT 50mACOUT = 4.7μF

VOUT = 3.3VCOUT = 10μF

200μs/DIV

35262b2f

VOUT100mV/DIVAC COUPLEDLOADCURRENT50mA/DIV

VIN = 3.6V100μs/DIVVOUT = 5V

20mA TO 170mA STEPCOUT = 10μF

35262b2f

VOUT100mV/DIVAC COUPLEDLOADCURRENT50mA/DIV

VIN = 3.6V100μs/DIVVOUT = 5V

50mA TO 150mA STEPCOUT = 10μF

35262b2f

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LTC3526-2/LTC3526B-2TYPICAL PERFORMANCE CHARACTERISTICS

Load Step Response (Fixed Frequency)VOUT100mV/DIVAC COUPLEDLOADCURRENT50mA/DIV

VIN = 1.2V100μs/DIVVOUT = 3.3V

50mA TO 100mA STEPCOUT = 10μF

35262b2f

Load Step Response (from Burst Mode Operation)PIN FUNCTIONS

SW (Pin 1): Switch Pin. Connect inductor between SW and VIN. Keep PCB trace lengths as short and wide as possible to reduce EMI. If the inductor current falls to zero or SHDN is low, an internal anti-ringing switch is connected from SW to VIN to minimize EMI.GND (Pin 2): Signal and Power Ground. Provide a short direct PCB path between GND and the (–) side of the input and output capacitors.VIN (Pin 3): Input Supply Pin. Connect a minimum of 1μF ceramic decoupling capacitor from this pin to ground using short direct PCB traces.SHDN (Pin 4): 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 5): Feedback Input to the gm Error Amplifinect resistor divider tap to this pin. The top of the divider connects to the output capacitor, the bottom of the divider connects to GND. Referring to the Block Diagram, the output voltage can be adjusted from 1.6V to 5.25V by: 󰀁R2󰀄

VOUT=1.195V•󰀂1+󰀅

󰀃R1󰀆

VOUT (Pin 6): Output voltage sense and drain of the internal synchronous rectifi er. PCB trace from VOUT to the output fi lter capacitor (4.7μF minimum) should be as short and wide as possible.Exposed Pad (Pin 7): The Exposed Pad must be soldered to the PCB ground plane. It serves as an additional ground connection and as a means of conducting heat away from the package.35262b2fa6元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2BLOCK DIAGRAM

VIN0.85VTO 5VL12.2μH

CIN2.2μFVOUT3VINVSELVBESTVB1SWWELLSWITCHVOUT1.6VTO 5.25VR2VOUTANTI-RINGGATE DRIVERSANDANTI-CROSSCONDUCTIONSHDN4MSHUTDOWNSHUTDOWN–+ΣIPKIZEROIPKCOMPSLOPECOMPFBIZEROCOMP5R1COUT4.7μF

–+UVLOSTART-UP2MHzOSCCLKLOGICMODECONTROLCLAMPTHERMALSHUTDOWNTSDWAKECSSEXPOSEDPAD7GND2+–VREF1.195VERROR AMPSLEEP COMPVREF35262b2f35262b2fa7元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2OPERATION

(Refer to Block Diagram)The LTC3526-2/LTC3526B-2 are 2MHz synchronous boost converters housed in a 6-lead 2mm × 2mm DFN package. With the ability to start up and operate from inputs less than 1V, these devices feature fi xed frequency, current mode PWM control for exceptional line and load regula-tion. The current mode architecture with adaptive slope compensation provides excellent transient load response, requiring minimal output fi ltering. Internal soft-start and internal loop compensation simplifi es the design process while minimizing the number of external components.With its low RDS(ON) and low gate charge internal N-chan-nel MOSFET switch and P-channel MOSFET synchronous rectifi er, the LTC3526-2 achieves high effi ciency over a wide range of load currents. Automatic Burst Mode operation maintains high effi ciency at very light loads, reducing the quiescent current to just 9μA. Operation can be best understood by referring to the Block Diagram.LOW VOLTAGE START-UPThe LTC3526-2/LTC3526B-2 include an independent start-up oscillator designed to start up at an input voltage of 0.85V (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. When 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 ap-plication becomes the availability of the power source to supply suffi cient energy to the output at low voltages, and 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-StartThe LTC3526-2/LTC3526B-2 contain internal circuitry to provide soft-start operation. The soft-start circuitry slowly ramps the peak inductor current from zero to its peak value of 700mA (typical) in approximately 0.5ms, allowing start-up into heavy loads. The soft-start circuitry is reset in the event of a shutdown command or a thermal shutdown.OscillatorAn internal oscillator sets the switching frequency to 2MHz.ShutdownShutdown is accomplished by pulling the SHDN pin below 0.3V and enabled by pulling the SHDN pin above 0.8V typical. 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 erThe positive input of the transconductance error amplifi er is internally connected to the 1.195V reference and the negative input is connected to FB. Clamps limit the mini-mum and maximum error amp output voltage for improved large-signal transient response. Power converter control loop compensation is provided internally. An external resistive voltage divider from VOUT to ground programs the output voltage via FB from 1.6V to 5.25V. 󰀁R2󰀄

V=1.195V•1+󰀂 OUT󰀃R1󰀅󰀆Current SensingLossless current sensing converts the peak current signal of the N-channel MOSFET switch into a voltage that 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 LimitThe current limit comparator shuts off the N-channel MOSFET switch once its threshold is reached. The cur-rent limit comparator delay to output is typically 60ns. Peak switch current is limited to approximately 700mA, independent of input or output voltage, unless VOUT falls below 0.7V, in which case the current limit is cut in half.35262b2fa8元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2OPERATION

(Refer to Block Diagram)Zero Current ComparatorThe zero current comparator monitors the inductor cur-rent to the output and shuts off the synchronous rectifi er when this current reduces to approximately 30mA. This prevents the inductor current from reversing in polarity, improving effi ciency at light loads.Synchronous Rectifi erTo control inrush current and to prevent the inductor current from running away when VOUT is close to VIN, the P-channel MOSFET synchronous rectifi er is only enabled when VOUT > (VIN + 0.24V).Anti-Ringing ControlThe anti-ringing control connects a resistor across the inductor to prevent high frequency ringing on the SW pin during discontinuous current mode operation. Although the ringing of the resonant circuit formed by L and CSW (capacitance on SW pin) is low energy, it can cause EMI radiation.Output DisconnectThe LTC3526-2/LTC3526B-2 are designed to allow true output disconnect by eliminating body diode conduction of the internal P-channel MOSFET rectifi er. This allows for VOUT to go to zero volts during shutdown, drawing no cur-rent from the input source. It also allows for 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 dis-connect feature also allows VOUT to be pulled high, without any reverse current into a battery connected to VIN.Thermal ShutdownIf the die temperature exceeds 160°C, the LTC3526-2/LTC3526B-2 will go into thermal shutdown. All switches will be off and the soft-start capacitor will be discharged. The device will be enabled again when the die temperature drops by about 15°C.Burst Mode OPERATIONThe LTC3526-2 will automatically enter Burst Mode opera-tion at light load and return to fi xed frequency PWM mode when the load increases. Refer to the Typical Performance Characteristics to see the output load Burst Mode thresh-old current 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 LTC3526-2 still switches at a fi xed frequency of 2MHz, 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, en-ergy is delivered to the output until it reaches the nominal regulation value, then the LTC3526-2 transitions to sleep mode where the outputs are off and the LTC3526-2 con-sumes only 9μA of quiescent current from VOUT. When the output voltage droops slightly, switching resumes. This maximizes effi ciency at very light loads by minimizing switching and quiescent losses. Burst Mode output voltage ripple, which is typically 1% peak-to-peak, can be reduced by using more output capacitance (10μF or greater), or with a small capacitor (10pF to 50pF) connected between VOUT and FB. As the load current increases, the LTC3526-2 will automati-cally leave Burst Mode operation. Note that larger output capacitor values may cause this transition to occur at lighter loads. Once the LTC3526-2 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 and soft-start and until VOUT is at least 0.24V greater than VIN.The LTC3526B-2 features continuous PWM operation at 2MHz. At very light loads, the LTC3526B-2 will exhibit pulse-skip operation.35262b2fa9元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2APPLICATIONS INFORMATION

VIN > VOUT OPERATIONThe LTC3526-2/LTC3526B-2 will maintain voltage regula-tion even when the input voltage is above the desired output voltage. Note that the effi ciency is much lower in this mode, and the maximum output current capability will be less. Refer to the Typical Performance Characteristics.SHORT-CIRCUIT PROTECTIONThe LTC3526-2/LTC3526B-2 output disconnect feature allows 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 400mA (typical).SCHOTTKY DIODEAlthough it is not required, adding a Schottky diode from ciency by about 2%. Note SW to VOUT will improve effithat this defeats the output disconnect and short-circuit protection features.PCB LAYOUT GUIDELINESThe high speed operation of the LTC3526-2/LTC3526B-2 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, but not absolutely necessary.COMPONENT SELECTIONInductor SelectionThe LTC3526-2/LTC3526B-2 can utilize small surface mount chip inductors due to their fast 2MHz switching frequency. Inductor values between 1.5μH and 3.3μH 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. 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:VIN(MIN)•VOUT(MAX)󰀁VIN(MIN)

2•RIPPLE•VOUT(MAX)

()Ripple = Allowable inductor current ripple (amps peak-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 reduce frequency depen-dent power losses compared to cheaper powdered iron types, improving effi ciency. The inductor should have low ESR (series resistance of the windings) to reduce the I2R power losses, and must be able to support the peak LTC3526-2SW16VOUTMINIMIZETRACE ON FBAND SWGND25FBVIN+VIN34SHDNMULTIPLE VIASTO GROUND PLANE35262b2fFigure 1. Recommended Component Placement for Single Layer Board35262b2fa10元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2APPLICATIONS INFORMATION

inductor current without saturating. Molded chokes and some chip inductors usually do not have enough core area to support the peak inductor currents of 700mA seen on the LTC3526-2/LTC3526B-2. To minimize radiated noise, use a shielded inductor. See Table 1 for suggested components and suppliers.Table 1. Recommended InductorsVENDORCoilcraft(847) 639-00www.coilcraft.comPART/STYLELPO4815LPS4012, LPS4018MSS5131MSS4020MOS6020ME3220DS1605, DO1608SD10, SD12, SD14, SD18, SD20, SD52, SD3114, SD3118MIP3226D4R7M, MIP3226D3R3MMIPF2520D4R7MIPWT3226D3R0LQH43CLQH32C (-53 series)301015CDRH5D18CDRH2D14CDRH3D16CDRH3D11CR43CMD4D06-4R7MCCMD4D06-3R3MCNP03SBNR3015TNR3012TVLPVLF, VLCFD412CD518LCD52LCD62LCBWE-TPC type S, MOutput and Input Capacitor SelectionLow ESR (equivalent series resistance) 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 4.7μF to 10μF output capacitor is suffi cient for most applications. Larger values up to 22μF 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.The internal loop compensation of the LTC3526-2 is de-signed to be stable with output capacitor values of 4.7μF or greater (without the need for any external series resistor). Although ceramic capacitors are recommended, low ESR tantalum capacitors may be used as well.A small ceramic capacitor in parallel with a larger tantalum capacitor may be used in demanding applications that have large load transients. Another method of improving the transient response is to add a small feed-forward capacitor across the top resistor of the feedback divider (from VOUT to FB). 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, although larger values may be used without limitations. Table 2 shows a list of several ceramic capacitor manufacturers. Consult the manufactur-ers directly for detailed information on their selection of ceramic capacitors.Table 2. Capacitor Vendor InformationSUPPLIERAVXMurataTaiyo-YudenTDKSamsungPHONE(803) 448-9411(714) 852-2001(408) 573-4150(847) 803-6100(408) 544-5200WEBSITEwww.avxcorp.comwww.murata.comwww.t-yuden.comwww.component.tdk.comwww.sem.samsung.comCoiltronicswww.cooperet.comFDK(408) 432-8331www.fdk.comMurata(714) 852-2001www.murata.comSumida(847) 956-0666www.sumida.comTaiyo-Yudenwww.t-yuden.comTDK(847) 803-6100www.component.tdk.comToko(408) 432-8282www.tokoam.comWurth(201) 785-8800www.we-online.com35262b2fa11元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2TYPICAL APPLICATIONS

1-Cell to 1.8V Converter with <1mm Maximum Heightfor Low-Noise Applications100

2.2μH*9080

VIN1V TO 1.6V1μFOFF ONEFFICIENCY (%)SWVINVOUT511k4.7μF**

1M35262b2fA02aVOUT = 1.8VLTC3526B-2SHDNGNDFBVOUT1.8V150mA7060504030201000.1

1

VIN = 1.5VVIN = 1.2VVIN = 0.9V10100

LOAD CURRENT (mA)

1000

35262b2f TA02b

*FDK MIPF2520D2R2**MURATA GRM219R60J475KE19D

1-Cell to 3.3V100

2.7μH*9080

VIN1V TO 1.6V1μFOFF ONEFFICIENCY (%)SWVINVOUT1.78M22pFLTC3526-2SHDNGNDFB1M35262b2fA04aVOUT = 3.3VVOUT3.3V75mA10μF

70605040302010

VIN = 1.5VVIN = 1.2VVIN = 0.9V0.1

110100LOAD CURRENT (mA)

1000

*TAIYO-YUDEN NP03SB2R7M

00.01

35262b2f TA04b

35262b2fa12元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2TYPICAL APPLICATIONS

2-Cell to 3.3V100

2.7μH*9080

VIN2V TO 3.2V1μFOFF ONVINVOUT1.78M4.7μF

1M35262b2fA05aVOUT = 3.3VEFFICIENCY (%)SWLTC3526-2SHDNGNDFBVOUT3.3V200mA7060504030201000.01

0.1

VIN = 3.0VVIN = 2.4VVIN = 1.8V110100LOAD CURRENT (mA)

1000

*TAIYO-YUDEN NP03SB2R7M

35262b2f TA05b

3.3V Converter with Output OR’d with 5V USB InputMBR120ESFT5V USB

2.2μHVOUT3.3V/5VUSB1.78MDC/DC4.7μF1M35262b2fA07aLDOVBATT

1.8V TO 3.2V

1μFOFF ONSWVINVOUTLTC3526-2SHDNGNDFB35262b2fa13元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2TYPICAL APPLICATIONS

2-Cell to 5V100

3.3μH*9080

VOUT5V150mA10μF

1.02M35262b2fA06aVOUT = 5VVIN2V TO 3.2V1μFOFF ONEFFICIENCY (%)SWVINVOUT3.24M22pFLTC3526-2SHDNGNDFB70605040302010

VIN = 3.0VVIN = 2.4VVIN = 1.8V0.1

110100LOAD CURRENT (mA)

1000

*TAIYO-YUDEN NP03SB3R3M

00.01

35262b2f TA06b

Li-Ion to 5V100

3.3μH*9080

VIN1μFOFF ONVOUT3.24M22pFEFFICIENCY (%)VIN2.7V TO 4.3VSWLTC3526-2SHDNGNDFB1.02M35262b2fA08aVOUT = 5VVOUT5V200mA10μF

7060504030201000.01

0.1

VIN = 4.2VVIN = 3.6VVIN = 3.0V110100LOAD CURRENT (mA)

1000

*TAIYO-YUDEN NP03SB3R3M

35262b2f TA08b

35262b2fa14元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2PACKAGE DESCRIPTION

DC Package6-Lead Plastic DFN (2mm × 2mm)(Reference LTC DWG # 05-08-1703)0.675±0.052.50±0.051.15±0.050.61±0.05(2 SIDES)PACKAGEOUTLINE2.00±0.10(4 SIDES)R = 0.115TYP0.56 ± 0.05(2 SIDES)0.38 ± 0.0546PIN 1 BARTOP MARK(SEE NOTE 6)PIN 1CHAMFER OFEXPOSED PAD31(DC6) DFN 1103

0.25 ± 0.050.50 BSC1.42±0.05(2 SIDES)RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS

0.200 REF0.75±0.050.25 ± 0.050.50 BSC1.37±0.05(2 SIDES)0.00 – 0.05BOTTOM VIEW—EXPOSED PADNOTE:

1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WCCD-2)2. 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

35262b2faInformation 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.15元器件交易网www.cecb2b.com

LTC3526-2/LTC3526B-2RELATED PARTS

PART NUMBERLT®1613LT1615LT1618LT1930/LT1930ALTC3400/LTC3400BLTC3401LTC3402LTC3421LTC3422LTC3423/LTC3424LTC3426LTC3427LTC3428LTC3429LTC3458LTC3458LDESCRIPTION800mA ISW, 1.4MHz, Step-Up DC/DC Converter350mA ISW, Micropower, Step-Up DC/DC Converter1.5A ISW, 1.4MHz, Constant Current/Constant Voltage Step-Up DC/DC Converter1A ISW, 1.2MHz/2.2MHz, Step-Up DC/DC Converters600mA ISW, 1.2MHz, Synchronous Step-Up DC/DC Converters1A ISW, 3MHz, Synchronous Step-Up DC/DC Converter2A ISW, 3MHz, Synchronous Step-Up DC/DC Converter3A ISW, 3MHz, Synchronous Step-Up DC/DC Converter with Output Disconnect1.5A ISW, 3MHz Synchronous Step-Up DC/DC Converter with Output Disconnect1A/2A ISW, 3MHz, Synchronous Step-Up DC/DC Converter2A ISW, 1.2MHz, Step-Up DC/DC Converter500mA ISW, 1.25MHz, Synchronous Step-Up DC/DC Converter with Output Disconnect 500mA ISW, 1.25MHz/2.5MHz, Synchronous Step-Up DC/DC Converters with Output Disconnect 600mA ISW, 500kHz, Synchronous Step-Up DC/DC Converter with Output Disconnect and Soft-Start1.4A 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 Disconnect500mA ISW, 1MHz, Synchronous Step-Up DC/DC Converter in 2mm × 2mm DFNCOMMENTSVIN: 1.1V to 10V, VOUT(MAX) = 34V, IQ = 3mA, ISD < 1μA, 5-Lead SOT-23 Package VIN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20μA, ISD < 1μA, ThinSOTTM PackageVIN: 1.6V to 18V, VOUT(MAX) = 35V, IQ = 1.8mA, ISD < 1μA, DFN, MSOP PackagesVIN: 2.6V to 16V, VOUT(MAX) = 34V, IQ = 4.2mA/5.5mA, ISD < 1μA, ThinSOT Package92% Effi ciency VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19μA/300μA, ISD < 1μA, ThinSOT Package97% Effi ciency VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD < 1μA, 10-Lead MS Package97% Effi ciency VIN: 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38μA, ISD < 1μA, 10-Lead MS Package95% Effi ciency VIN: 0.5V to 4.5V, VOUT(MAX) = 5.25V, IQ = 12μA, ISD < 1μA, QFN24 Package95% 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 PackageVIN: 1.8V to 5V, VOUT(MAX) = 5.25V, IQ = 350μA, ISD < 1μA, 2mm × 2mm DFN Package92% Effi ciency VIN: 1.8V to 5V, VOUT(MAX) = 5.25V, ISD < 1µA, 2mm × 2mm DFN Package96% Effi ciency VIN: 0.5V to 4.4V, VOUT(MAX) = 5V, IQ = 20μA/300μA, ISD < 1μA, ThinSOT Package93% 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 Package LTC3459LTC3525-3LTC3525-3.3 LTC3525-5LTC3526/LTC3526BVIN: 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 PackageVIN: 1V to 5V, VOUT(MAX) = 5.25V, IQ = 9µA, ISD < 1μA, 2mm × 2mm DFN PackageThinSOT is a trademark of Linear Technology Corporation.35262b2fa16Linear Technology CorporationLT 0807 REV A • PRINTED IN USA

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