LTC4449

6

4449f

BLOCK DIAGRAM

PIN FUNCTIONS

TG (Pin 1): High Side Gate Driver Output (Top Gate). This

pin swings between TS and BOOST.

TS (Pin 2): High Side MOSFET Source Connection (Top

Source).

BG (Pin 3): Low Side Gate Driver Output (Bottom Gate).

GND (Pin 4, Exposed Pad Pin 9): Chip Ground. The

exposed pad must be soldered to PCB ground for optimal

electrical and thermal performance.

IN (Pin 5): Input Signal. Input referenced to an internal

this pin is floating, an internal resistive divider triggers a

shutdown mode in which both BG (Pin 5) and TG (Pin 3)

are pulled low. Trace capacitance on this pin should be

minimized to keep the shutdown time low.

buffer and logic. Connect this pin to the power supply

of the controller that is driving IN (Pin 7) to match input

side gate driver output directly and the high side gate driver

outputthroughanexternalSchottkydiodeconnectedbetween

this pin and BOOST. A low ESR ceramic bypass capacitor

should be tied between this pin and GND (Pin 6).

BOOST (Pin 8): High Side Bootstrapped Supply. An

external capacitor should be tied between this pin and TS

(Pin 4). Normally an external Schottky diode is connected

forward voltage drop of the Schottky diode.

8

1

2

SHOOT-

THROUGH

PROTECTION

THREE-STATE

INPUT

BUFFER

LEVEL

SHIFTER

INTERNAL

SUPPLY

UNDERVOLTAGE

LOCKOUT

UNDERVOLTAGE

LOCKOUT

BOOST

TG

TS

3

6

BG

4449 BD

7k

7k

7

5

IN

4

GND

9

GND