LTC3429/LTC3429B

1

3429fa

■

MP3 Players

■

Handheld Instruments

600mA, 500kHz Micropower

Synchronous Boost Converter

with Output Disconnect

Figure 1. 2-Cell to 3.3V Synchronous Boost Converter

SW

4.7µH

LTC3429

FB

SHDN

3429 F01a

1.02M

604k

10µF

4.7µF

2-CELL

AA

+

3.3V

250mA

GND

OFF ON

2-Cell to 3.3V Efficiency

OUTPUT CURRENT (mA)

60

80

100

50

70

90

0.1

10

100

1000

3429 F01b

40

1

0.01

1

100

0.001

0.1

10

0.0001

EFFICIENCY

POWER LOSS

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

The LTC

nous, fixed frequency, step-up DC/DC converters with true

output load disconnect, inrush current limiting and soft-

start in a low profile 6-lead ThinSOT

devices are capable of supplying 100mA from a single AA

cell input or 250mA from a 2-cell AA with a 3.3V output.

A switching frequency of 500kHz minimizes overall solu-

tion footprint by allowing the use of tiny, low profile

inductors and ceramic capacitors. Current mode PWM

control with internal compensation reduces external parts

count thereby saving critical board real estate. The LTC3429

shifts automatically to power saving Burst Mode operation

at light loads while the LTC3429B features continuous

switching at light loads. Antiringing control circuitry re-

duces EMI concerns by damping the inductor in discon-

tinuous mode.

The devices also feature low shutdown current of under

1µA. The true output disconnect feature allows the output

to be completely discharged in shutdown. It also limits the

inrush of current during start-up, minimizing surge cur-

rents seen by the input supply.

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

trademarks are the property of their respective owners. Burst Mode is a registered

trademark of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology

Corporation.