LTC3407

1

sn3407 3407fs

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

■

1.5MHz Constant Frequency Operation

■

and Load Transient Response

■

Short-Circuit Protected

■

Output Voltages from 5V down to 0.6V

■

Small Thermally Enhanced MSOP and 3mm × 3mm

DFN Packages

Dual Synchronous, 600mA,

1.5MHz Step-Down

DC/DC Regulator

The LTC

step down DC/DC converter. Intended for low power

applications, it operates from 2.5V to 5.5V input voltage

range and has a constant 1.5MHz switching frequency,

allowing the use of tiny, low cost capacitors and inductors

2mm or less in height. Each output voltage is adjustable

from 0.6V to 5V. Internal synchronous 0.35Ω, 1A power

switches provide high efficiency without the need for

external Schottky diodes.

A user selectable mode input is provided to allow the user

to trade-off ripple noise for low power efficiency. Burst

Mode

while Pulse Skip Mode provides low ripple noise at light

loads.

To further maximize battery life, the P-channel MOSFETs

are turned on continuously in dropout (100% duty cycle),

and both channels draw a total quiescent current of only

40µA. In shutdown, the device draws <1µA.

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

Burst Mode is a registered trademark of Linear Technology Corporation.

LTC3407 Efficiency Curve

Figure 1. 2.5V/1.8V at 600mA Step-Down Regulators

RUN2

TO 5.5V

AT 600mA

AT 600mA

RUN1

POR

SW1

GND

SW2

MODE/SYNC

LTC3407

C1

10µF

R5

100k

RESET

C4, 22pF

C5, 22pF

L1

2.2µH

L2

2.2µH

R4

887k

R2

887k

R1

442k

R3

280k

C3

10µF

C2

10µF

3407 TA01

C1, C2, C3: TAIYO YUDEN JMK316BJ106ML

L1, L2: MURATA LQH32CN2R2M33

LOAD CURRENT (mA)

1

100

95

90

85

80

75

70

65

60

10

100

1000

3407 TA02

Burst Mode OPERATION

NO LOAD ON OTHER CHANNEL

2.5V

1.8V