LTC3527/LTC3527-1

1

35271f

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Dual 800mA/400mA,

1.2MHz/2.2MHz Synchronous

Step-Up DC/DC Converters

step-up DC/DC converters in a space saving 16-lead 3mm

× 3mm QFN package. Battery life is maximized with a

700mV start-up voltage and operation down to 500mV

once started. The ⎯S⎯H⎯D⎯N and PGOOD pins enable the

converters to be sequenced or started together.

The LTC3527/LTC3527-1 limit inrush current during start-

up. Selectable 1.2MHz or 2.2MHz operation provides a

choice between the highest efficiency or smallest solu-

tion footprint. The current mode PWM design is internally

compensated reducing external parts count. Burst Mode

operation or fixed frequency operation is selectable via the

MODE pin. Anti-ring circuitry reduces EMI in discontinuous

mode. This device also features thermal shutdown.

True output disconnect allows the output to be completely

open in shutdown. The LTC3527-1 actively discharges

escent current in shutdown is less than 2µA.

1.2MHz Efficiency and Power Loss

■

Dual Synchronous Step-Up DC/DC Converters

■

Delivers 3.3V at 200mA/100mA from one Alkaline/

NiMH Cell, or 3.3V at 400mA/200mA from Two Cells

■

■

■

■

Output Disconnect in Shutdown

■

■

1.2MHz or 2.2MHz Operation

■

Up to 94% Efficiency

■

■

Inrush Current Limiting and Soft-Start

■

Internal Synchronous Rectifiers

■

Logic-Controlled Shutdown (< 2µA)

■

■

16-Lead, 0.75mm × 3mm × 3mm QFN Package

■

MP3/Personal Media Players

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Noise Canceling / Bluetooth Headsets

■

Wireless Mice

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Portable Medical Instruments

, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology

Corporation. All other trademarks are the property of their respective owners.

LOAD CURRENT (mA)

30

90

100

20

10

80

50

70

60

40

0.01

1

100

10

1000

35271 TA01b

0

1000

0.1

100

10

1

0.01

0.1

BURST

EFFICIENCY

FIXED

FREQUENCY

POWER

LOSS

BURST

Two-Cell Alkaline to 3.3V/1.8V Synchronous Boost Converters

35271 TA01

+

ON

OFF

4.7

µF

LTC3527

4.7

µH

4.7

µH

4.7

µF

4.7

µF

1.6V to 3.2V

SW1

FB1

PGOOD1

SHDN1

SW2

FB2

PGOOD2

SHDN2

MODE

GND

3.3V

150mA

1.8V

150mA

1.78M

1M

619k

1.21M

ON

OFF