LTC3549

7

3549f

PI FU CTIO S

to GND, Pins 2 and 7, with a 4.7µF or greater ceramic

capacitor.

GND (Pin 2): N/C. Ground this pin.

SW (Pin 3): Switch Node Connection to Inductor. This pin

connects to the drains of the internal main and synchronous

power MOSFET switches.

MODE (Pin 4): Mode Select Input. To select pulse-skip-

ping mode, force this pin above 1.1V. Forcing this pin

below 0.3V selects Burst Mode operation. Do not leave

MODE floating.

RUN (Pin 5): Run Control Input. Forcing this pin above 1.1V

enables the part. Forcing this pin below 0.3V shuts down

the device. In shutdown, all functions are disabled drawing

<1µA supply current. Do not leave RUN floating.

from an external resistive divider across the output.

GND (Pin 7): Exposed Pad. The Exposed Pad is ground. It

must be soldered to PCB ground to provide both electrical

contact and optimum thermal performance.

FU CTIO AL DIAGRA

+

–

+

–

EA

+

–

OVDET

+

–

6

5

RUN

SLOPE

COMP

OSC

0.611V

REFERENCE

SHUTDOWN

OV

0.671

0.4V

0.65V

SLEEP

EN

4

MODE

BURST

S

R

RS LATCH

SWITCHING

LOGIC

AND

BLANKING

CIRCUIT

ANTI-

SHOOT-

THRU

SOFT-

START

Q

Q

5

Ω

1

SW

3

GND

3549 FD

2

GND

7

OSCILLATOR