LTC4449

1

4449fa

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

High Speed Synchronous

N-Channel MOSFET Driver

The LTC

is designed to drive two N-Channel MOSFETs in a

synchronous DC/DC converter. The powerful rail-to-rail

driver capability reduces switching losses in MOSFETs

with high gate capacitance.

The LTC4449 features a separate supply for the input logic

to match the signal swing of the controller IC. If the input

signal is not being driven, the LTC4449 activates a shutdown

mode that turns off both external MOSFETs. The input logic

signal is internally level-shifted to the bootstrapped supply,

which functions at up to 42V above ground.

The LTC4449 contains undervoltage lockout circuits on

both the driver and logic supplies that turn off the external

MOSFETs when an undervoltage condition is present. An

adaptive shoot-through protection feature is also built-in

to prevent the power loss resulting from MOSFET cross-

conduction current.

The LTC4449 is available in the 2mm × 3mm DFN

package.

Synchronous Buck Converter Driver

LTC4449 Driving 3000pF Capacitive Loads

TG

BOOST

TO 38V

GND

TS

LTC4449

BG

PWM

4V TO 6.5V

IN

4449 TA01a

TOP GATE

(TG - TS)

5V/DIV

INPUT (IN)

5V/DIV

4449 TA01b

BOTTOM GATE

(BG) 5V/DIV

10ns/DIV

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

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