1

LTC3251/

LTC3251-1.2/LTC3251-1.5

32511215fb

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

500mA High Efficiency,

Low Noise, Inductorless

Step-Down DC/DC Converter

Spread Spectrum Step-Down Converter

1.5V Efficiency vs Input Voltage

(Burst Mode Operation)

The LTC

charge pump step-down DC/DC converters that produce a

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

switched capacitor fractional conversion to achieve twice

the typical efficiency of a linear regulator. No inductors are

or fixed at 1.2V or 1.5V, with up to 500mA of load current

available.

A unique 2-phase spread spectrum architecture provides

a very low noise regulated output as well as low noise at the

input.* The parts have four operating modes: Continuous

Spread Spectrum, Spread Spectrum with Burst Mode

operation, Super Burst

Low operating current (35

µA in Burst Mode operation,

10

µA in Super Burst mode operation) and low external

parts count make the LTC3251/LTC3251-1.2/LTC3251-1.5

ideally suited for space-constrained battery-powered

applications. The parts are short-circuit and overtempera-

ture protected, and are available in a thermally enhanced

10-pin MSOP package.

for Low Input and Output Noise

Fixed Output Voltages: 1.2V, 1.5V

®

Operation)

10-Pin MSOP Package

■

Portable Electronic Equipment

MD0 MD1

LTC3251-1.5

1

µF

1

µF

1-CELL Li-Ion

OR

3-CELL NiMH

OFF ON

GND

MODE

1

µF

10

µF

500mA

3251 TA01

19

2

3

4

5, 11

7

8

6

10

INPUT VOLTAGE (V)

3

60

80

100

5

3251 TA02

40

20

50

70

90

30

10

0

3.5

4

4.5

5.5

LTC3251-1.5

LDO

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

Burst Mode is a registered trademark of Linear Technology Corporation.

Super Burst is a trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by US Patents including 6411531.