LTC3548A

1

3548af

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

Dual Synchronous

400mA/800mA, 2.25MHz

Step-Down DC/DC Regulator

step-down DC/DC converter. Intended for low power ap-

plications, it operates from a 2.5V to 5.5V input voltage

range and has a constant 2.25MHz switching frequency,

enabling the use of tiny, low cost capacitors and inductors

1mm or less in height. Each output voltage is adjustable

from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A

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

loads, while pulse-skipping mode provides the lowest

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.

2.5V/1.8V at 400mA/800mA Step-Down Regulators

and Load Transient Response

× 3mm

DFN Packages

Efficiency/Power Loss Curves

L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks

of Linear Technology Corporation. All other trademarks are the property of their respective

owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466,

6611131.

2.5V TO 5.5V

2.5V

400mA

1.8V

800mA

RUN/SS1

POR

SW1

GND

SW2

MODE/SYNC

LTC3548A

10μF

100k

RESET

22pF

22pF

2.2μH

4.7μH

887k

887k

442k

280k

4.7μF

10μF

3548A TA01

LOAD CURRENT (mA)

1

0

30

20

10

70

60

50

40

100

0.0001

0.001

0.1

0.01

1

90

80

10

100

1000

3548A TA02

2.5V

Burst Mode OPERATION

NO LOAD ON OTHER CHANNEL

1.8V