1

LTC3406

LTC3406-1.5/LTC3406-1.8

3406fa

■

High Efficiency: Up to 96%

■

Very Low Quiescent Current: Only 20

During Operation

■

600mA Output Current

■

2.5V to 5.5V Input Voltage Range

■

1.5MHz Constant Frequency Operation

■

No Schottky Diode Required

■

Low Dropout Operation: 100% Duty Cycle

■

0.6V Reference Allows Low Output Voltages

■

Shutdown Mode Draws ≤ 1µA Supply Current

■

Current Mode Operation for Excellent Line and

Load Transient Response

■

Overtemperature Protected

■

Low Profile (1mm) ThinSOT

The LTC

nous buck regulator using a constant frequency, current

mode architecture. The device is available in an adjustable

version and fixed output voltages of 1.5V and 1.8V. Supply

current during operation is only 20µA and drops to ≤1µA

in shutdown. The 2.5V to 5.5V input voltage range makes

the LTC3406 ideally suited for single Li-Ion battery-pow-

ered applications. 100% duty cycle provides low dropout

operation, extending battery life in portable systems.

Automatic Burst Mode

light loads, further extending battery life.

Switching frequency is internally set at 1.5MHz, allowing

the use of small surface mount inductors and capacitors.

The internal synchronous switch increases efficiency and

eliminates the need for an external Schottky diode. Low

output voltages are easily supported with the 0.6V feed-

back reference voltage. The LTC3406 is available in a low

profile (1mm) ThinSOT package.

■

Cellular Telephones

Figure 1a. High Efficiency Step-Down Converter

1.5MHz, 600mA

Synchronous Step-Down

Regulator in ThinSOT

Figure 1b. Efficiency vs Load Current

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

Burst Mode is a registered trademark of Linear Technology Corporation.

ThinSOT is a trademark of Linear Technology Corporation.

Protected by U.S. Patents, including 6580258, 5481178.

4.7µF

CER

2.7V

TO 5.5V

*

**

†

LTC3406-1.8

RUN

3

2.2µH*

3406 F01a

MURATA LQH32CN2R2M33

TAIYO YUDEN JMK212BJ475MG

TAIYO YUDEN JMK316BJ106ML

5

4

1

2

SW

GND

10µF

CER

1.8V

600mA

OUTPUT CURRENT (mA)

70

80

90

95

0.1

10

100

1000

3406 F01b

60

1

85

75

65

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO