LTC3250-1.5/LTC3250-1.2

1

3250fa

DESCRIPTIO

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

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Handheld Computers

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Cellular Phones

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Digital Cameras

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Handheld Medical Instruments

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Low Power DSP Supplies

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2.7V to 5.5V Input Voltage Range

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No Inductors

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Li-Ion (3.6V) to 1.5V with 81% Efficiency

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Low Noise Constant Frequency Operation

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Output Voltages: 1.5V

±4%, 1.2V ±4%

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Output Current: 250mA

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s

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Oscillator Frequency = 1.5MHz

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Soft-Start Limits Inrush Current at Turn-On

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Short-Circuit and Overtemperature Protected

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Low Profile (1mm) SOT-23 Package

High Efficiency, Low Noise,

Inductorless Step-Down

DC/DC Converter

3250 TA1a

LTC3250-1.5

3.2V TO 4.2V

SHDN

GND

ON

OFF

1

µF

4.7

µF

100mA

Li-Ion

1

µF

Efficiency vs Input Voltage

The LTC

down DC/DC converters that produce a 1.5V or 1.2V

regulated output from a 2.7V to 5.5V input. The parts use

switched capacitor fractional conversion to achieve typi-

cal efficiency two times higher than that of a linear regu-

lator. No inductors are required.

A unique constant frequency architecture provides a low

noise regulated output as well as lower input noise

than conventional charge pump regulators.* High

to further reduce conducted noise. The part also uses

Burst Mode

Low operating current (35

µA with no load, <1µA in

shutdown) and low external parts count (three small

ceramic capacitors) make the LTC3250-1.5/LTC3250-1.2

ideally suited for space constrained battery powered appli-

cations. The parts are short-circuit and overtemperature

protected, and are available in a low profile (1mm) 6-pin

ThinSOT

3.0

3.5

4.0

4.5

5.0

5.5

3250 TA01b

100

90

80

70

60

50

40

30

20

10

0

LDO

LTC3250-1.5

Li-Ion to 1.5V Output with Shutdown

, LTC and LT are registered trademarks of Linear Technology Corporation

Burst Mode is a registered trademark of Linear Technology Corporation

ThinSOT is a trademark of Linear Technology Corporation.

*U.S. Patent #6, 411, 531