LTC3422

1

3422fa

■

GPS Receivers

for Li-Ion to 5V Applications

100kHz to 3MHz

µA

µA Shutdown Current

× 3mm × 0.75mm) Thermally Enhanced

10-Pin DFN Package

1.5A, 3MHz Synchronous

Step-Up DC/DC Converter

with Output Disconnect

2.4V to 3.3V Efficiency and Power Loss

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO

The LTC

frequency, step-up DC/DC converter with true output

disconnect and inrush current limiting. The part is guaran-

teed to start up from an input voltage of 1V. The device

includes a 0.20

Ω N-channel MOSFET switch and a 0.24Ω

P-channel MOSFET synchronous rectifier. The output

voltage, switching frequency, soft-start time, Burst Mode

threshold and loop compensation are all simply pro-

grammed using tiny external passive components.

Quiescent current is only 25

µA during Burst Mode opera-

tion, maximizing battery life in portable applications. The

oscillator frequency can be programmed up to 3MHz and

can be synchronized to an external clock applied to the

SYNC pin.

Other features include 1

µAshutdown,short-circuitprotec-

tion, anti-ringing control, thermal shutdown and current

limit. The LTC3422 is available in a (3mm

×3mm×0.75mm)

10-pin DFN package.

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

Burst Mode is a registered trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

0.1

µF

1nF

OFF ON

15k

22

µF

4.7

µF

1.8V TO 3.2V

2 CELLS

+

2.2nF

28k

931k

3.3V

600mA

549k

301k

3422 TA01a

SS

BURST

SHDN

FB

SYNC

GND

LTC3422

4.7

µH

SW

22pF

LOAD CURRENT (mA)

30

90

100

20

10

80

50

70

60

40

0.1

10

100

1000

3422 TA01b

0

1000

10000

100

10

1

0

1

BURST

EFFICIENCY

PWM

EFFICIENCY

BURST

POWER

LOSSES

PWM

POWER

LOSSES