1

LTC3404

3404fb

APPLICATIO S

FEATURES

DESCRIPTIO

TYPICAL APPLICATIO

During Operation

Pulse Skipping Mode

μA Supply Current

■

±2% Output Voltage Accuracy

Load Transient Response

The LTC

nous buck regulator using a constant frequency, current

mode architecture. Supply current during operation is

only 10

μA and drops to < 1μA in shutdown. The 2.65V to

6V input voltage range makes the LTC3404 ideally suited

for single Li-Ion battery-powered applications. 100% duty

cycle provides low dropout operation, extending battery

life in portable systems.

Switching frequency is internally set at 1.4MHz, allowing

the use of small surface mount inductors and capacitors.

For noise sensitive applications the LTC3404 can be

externally synchronized from 1MHz to 1.7MHz. Burst

Mode operation is inhibited during synchronization or

when the SYNC/MODE pin is pulled low, preventing low

frequency ripple from interfering with audio circuitry.

The internal synchronous switch increases efficiency and

eliminates the need for an external Schottky diode. Low

output voltages are easily supported with the 0.8V feed-

back reference voltage. The LTC3404 is available in a

space saving 8-lead MSOP package.

For higher input voltage (11V abs max) applications, refer

to the LTC1877 data sheet.

High Efficiency Step-Down Converter

1.4MHz High Efficiency

Monolithic Synchronous

Step-Down Regulator

Efficiency vs Output Load Current

LOAD (mA)

80

75

85

90

95

100

0.1

10

100

1000

3404 TA02

70

1

Burst Mode OPERATION

L = 4.7

μH

22

μF**

CER

7

6

1

2

5

3

4

SW

LTC3404

GND

4.7

μH*

10

μF***

CER

47pF

†

3.3V

*

**

***

†

TOKO D52LC A914BYW-4R7M

TAIYO-YUDEN CERAMIC JMK325BJ226MM

TAIYO-YUDEN CERAMIC LMK325BJ106MN

887k

20pF

280k

3404 TA01

SYNC

RUN

2.65V

TO 6V

, 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.