LTC3252

1

3252f

The LTC

converter that produces two adjustable regulated outputs

from a single 2.7V to 5.5V input. The part uses switched

capacitor fractional conversion to achieve a typical effi-

ciency increase of 50% over that of a linear regulator. No

inductors are required.

A unique constant frequency, spread spectrum architec-

ture provides a very low noise regulated output as well as

low noise at the input. The part also has Burst Mode

®

operation to provide high efficiency at low output currents,

as well as ultralow current shutdown.

Low operating currents (60

µA with both outputs enabled,

35

µA with one output enabled) and low external parts

count make the LTC3252 ideally suited for space-con-

strained battery-powered applications. The part is short-

circuit and overtemperature protected and is available in a

tiny 4mm

× 3mm 12-pin DFN package.

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Handheld Electronic Devices

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Cellular Phones

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Low Voltage Logic Supplies

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DSP Power Supplies

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3.3V to 1.5V Conversion

, LTC and LT are registered trademarks of Linear Technology Corporation.

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2.7V to 5.5V Input Voltage Range

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No Inductors

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Typical Efficiency 50% Higher than LDOs

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Spread Spectrum Operation

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Low Input and Output Noise

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Dual Adjustable Independent Outputs

(Range: 0.9V to 1.6V)

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Output Current: 250mA Each Output

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(35

µA with One Output Enabled)

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Soft-Start Limits Inrush Current at Turn On

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Short Circuit and Over Temperature Protected

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Available in 4mm

× 3mm 12-Pin DFN Package

Dual, Low Noise,

Inductorless Step-Down

DC/DC Converter

Burst Mode is a registered trademark of Linear Technology Corporation.

1.5V and 1.2V Output Voltages with Shutdown

470k

5

510k

4.7

µF

OUT1

1

FB1

261k

9

510k

4.7

µF

LTC3252

3252 TA01

1-CELL

Li-ION

OR 3-CELL

NiMH

4.7

µF

1

µF

OUT2

12

FB2

2

EN1

3

10

8

1

µF

4

6

7

GND

OFF ON

11

EN2

OFF ON

1.5V/1.2V Efficiency vs Input Voltage

2.7

100

90

80

70

60

50

40

30

20

10

0

3252 TA01a

3.1

3.5

3.9

4.3

4.7

5.1

5.5

LTC3252-1.5V

LTC3252-1.2V

LDO-1.5V

LDO-1.2V

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO