LTC3442 查看數據表（PDF） - Linear Integrated System

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LTC3442

Micropower Synchronous Buck-Boost DC/DC Converter with Automatic Burst Mode Operation

Linear Integrated System 

LTC3442

Micropower Synchronous

Buck-Boost DC/DC Converter with

Automatic Burst Mode Operation

FEATURES

DESCRIPTIO

■ Regulated Output with Input Voltages Above,

Below, or Equal to the Output

■ Single Inductor, No Schottky Diodes Required

■ Manual or Programmable Automatic Burst Mode®

Operation

■ Programmable Average Input Current Limit

■ Up to 1.2A Continuous Output Current from a Single

Lithium-Ion Cell

■ High Efficiency: Up to 95%

■ Output Disconnect in Shutdown

■ 2.4V to 5.5V Input Range

■ 2.4V to 5.25V Output Range

■ 35µA Quiescent Current in Burst Mode Operation

■ Programmable Frequency from 300kHz to 2MHz

■ <1µA Shutdown Current

■ Small, Thermally Enhanced 12-Lead (4mm × 3mm)

DFN Package

U

APPLICATIO S

■ PDA/‘SMART’ Phones

■ Handheld Computers

■ MP3 Players

■ Handheld Instruments

■ Digital Cameras

■ Wireless Handsets

■ USB Peripherals

The LTC®3442 is a highly efficient, fixed frequency, Buck-

Boost DC/DC converter, which operates from input volt-

ages above, below, and equal to the output voltage. The

topology incorporated in the IC provides a continuous

transfer function through all operating modes, making the

product ideal for a single Lithium-Ion or multicell alkaline

applications where the output voltage is within the battery

voltage range.

The device includes two 0.10Ω N-channel MOSFET

switches and two 0.10Ω P-channel switches. Operating

frequency and average input current limit can each be

programmed with an external resistor. Quiescent current

is only 35µA in Burst Mode operation, maximizing battery

life in portable applications. Automatic Burst Mode opera-

tion allows the user to program the load current for Burst

Mode operation, or to control it manually.

Other features include 1µA shutdown current, program-

mable soft-start, peak current limit and thermal shutdown.

The LTC3442 is available in a low profile, thermally en-

hanced 12-lead (4mm × 3mm × 0.75mm) DFN package.

, 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. Protected by U.S. Patents including 6404251,

6166527.

TYPICAL APPLICATIO

4.7µH

VIN

2.5V TO

4.2V

Li-Ion

10µF

1M

0.01µF

71.5k

SW1

SW2

VIN

VOUT

LTC3442

SHDN/SS

FB

RLIM

VC

RT

SGND

BURST

PGND

340k

2.2k

VOUT

3.3V

1.2A

15k

470pF

220pF

22µF

0.01µF

200k

200k

3442 TA01a

Efficiency vs VIN

100

300mA LOAD

90

1A LOAD

80

70

60

VOUT = 3.3V

L = 4.7µH

F = 600kHz

50

2.5 3.0 3.5 4.0 4.5 5.0 5.5

VIN (V)

3442 • TA01b

3442f

1

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