1

LTC3401

3401fa

APPLICATIO S

DESCRIPTIO

FEATURES

1A, 3MHz Micropower

Synchronous Boost Converter

The LTC

up DC/DC converter that operates from an input voltage

below 1V. The device includes a 0.16

ΩN-channelMOSFET

switch and a 0.18

Ω P-channel synchronous rectifier.

Switching frequencies up to 3MHz are programmed with

an external timing resistor and the oscillator can be

synchronized to an external clock. An external Schottky

diode is optional but will slightly improve efficiency.

Quiescent current is only 38

µA in Burst Mode operation,

maximizing battery life in portable applications. Burst

Mode operation is user controlled and can be enabled by

driving the MODE/SYNC pin high. If the MODE/SYNC pin

has either a clock or is driven low, then fixed frequency

switching is enabled.

Other features include 1

µA shutdown, antiringing control,

open-drain power good output, thermal shutdown and

current limit. The LTC3401 is available in the 10-lead

thermally enhanced MSOP package. Higher current appli-

cations should use the 2A rated LTC3402 synchronous

should use the LTC3423.

All-Ceramic-Capacitor 2-Cell to 3.3V at 500mA Step-Up Converter

s

Pagers

s

Handheld Instruments

s

Cordless Phones

s

Wireless Handsets

s

GPS Receivers

s

Battery Backup

s

CCFL Backlights

s

Synchronous Rectification: Up to 97% Efficiency

s

1A Switch Current Rating

s

Fixed Frequency Operation Up to 3MHz

s

Wide Input Range: 0.5V to 5.5V (Operating)

s

Very Low Quiescent Current: 38

Operation)

s

2.6V to 5.5V Adjustable Output Voltage

s

0.85V (Typ) Start-Up Voltage

s

s

Synchronizable Switching Frequency

s

Burst Mode Enable Control

s

Antiringing Control Reduces Switching Noise

s

PGOOD Output

s

OPTI-LOOP

s

Very Low Shutdown Current: < 1

µA

s

Small 10-Pin MSOP Package

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

Burst Mode and OPTI-LOOP are registered trademarks of Linear Technology Corporation.

0.1

0

10

30

40

50

100

70

3401 TA02

20

80

90

60

110

100

1000

Burst Mode

OPERATION

1MHz

FIXED

FREQUENCY

Efficiency

3

10

2

6

1

3404 TA01

LTC3401

SHDN

MODE/SYNC

PGOOD

SW

FB

GND

4

7

8

9

5

C3

470pF

C4

4.7pF

2

CELLS

C1

4.7

µF

R5

82k

30.1k

R2

909k

R1

549k

3.3V

500mA

L1

4.7

µH

C2

22

µF

C1: TAIYO YUDEN JMK212BJ475MG

C2: TAIYO YUDEN JMK325BJ226MM

L1: SUMIDA CD43-4R7M

0 = FIXED FREQUENCY

1 = Burst Mode OPERATION

+