1

LT1944

Dual Micropower Step-Up

DC/DC Converter

The LT

verter in a 10-pin MSOP package. Each converter is

designed with a 350mA current limit and an input voltage

range of 1.2V to 15V, making the LT1944 ideal for a wide

variety of applications. Both converters feature a quies-

cent current of only 20

µAatnoload,whichfurtherreduces

to 0.5

µA in shutdown. A current limited, fixed off-time

control scheme conserves operating current, resulting in

high efficiency over a broad range of load current. The 36V

switch allows high voltage outputs up to 34V to be easily

generated in a simple boost topology without the use of

costly transformers. The LT1944’s low off-time of 400ns

permits the use of tiny, low profile inductors and capaci-

tors to minimize footprint and cost in space-conscious

portable applications.

s

Low Quiescent Current:

20

<1

s

s

s

Uses Small Surface Mount Components

s

High Output Voltage: Up to 34V

s

Tiny 10-Pin MSOP Package

s

LCD Bias

s

Handheld Computers

s

Battery Backup

s

Digital Cameras

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

SW1

FB2

LT1944

4

3

L1

4.7

µH

D1

SHDN2

324k

1M

C2

10

µF

5V

80mA

30V

8mA

2.7V

TO 4.2V

1944 TA01

GND

7

PGND

9

PGND

6

810

SW2

4.7pF

C1

4.7

µF

FB1

2

5

1

SHDN1

L2

10

µH

D2

2M

86.6k

C3

1

µF

4.7pF

C1: TAIYO YUDEN JMK212BJ475

C2: TAIYO YUDEN JMK316BJ106

C3: TAIYO YUDEN GMK316BJ105

D1, D2: ON SEMI MBR0540

L1: MURATA LQH3C4R7

L2: MURATA LQH3C100

LOAD CURRENT (mA)

0.1

1

10

100

1944 TA01a

90

85

80

75

70

65

60

55

50

Dual Output (5V, 30V) Boost Converter

5V Output Efficiency

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO