NSC LM2724ALD, LM2724AMX, LM2724AM, LM2724ALDX Datasheet

LM2724A
High Speed 3A Synchronous MOSFET Driver

General Description

The LM2724A is a dual N-channel MOSFET driver which
can drive both the top and bottom MOSFETs in a push-pull
structure simultaneously. The LM2724A takes a logic input
and splits it into two complimentary signals with a typical
20ns dead time in between. The built-in cross-conduction
protection circuitry prevents the top and bottom MOSFETs
from turning on simultaneously. With a bias voltage of 5V, the
peak sourcing and sinking current for each driver of the
LM2724A is about 3A. Input UVLO (Under-Voltage-Lock­Out) ensures that all the driver outputs stay low until the
supply rail exceeds the power-on threshold during system
power on, or after the supply rail drops below power-on
threshold by a specified hysteresis during system power
down. The cross-conduction protection circuitry detects both
driver outputs and will not turn on a driver until the other
driver output is low. The top gate voltage needed by the top
MOSFET is obtained through an external boot-strap struc­ture. When not switching, the LM2724A only draws up to

195µA from the 5V rail. The synchronization operation of the
bottom MOSFET can be disabled by pulling the SYNC pin to
ground.

Features

n Shoot-through protection
n Input Under-Voltage-Lock-Out
n 3A peak driving current
n 195µA quiescent current
n 28V input voltage in buck configuration
n SO-8 and LLP packages

Applications

n High Current DC/DC Power Supplies
n High Input Voltage Switching Regulators
n Fast Transient Microprocessors
n Notebook Computers

LM2724A High Speed 3A Synchronous MOSFET Driver

June 2003

Typical Application

20073501

© 2003 National Semiconductor Corporation DS200735 www.national.com

Connection Diagram

LM2724A

8-Lead SO (NS Package # M08A)

20073502

= 172˚C/W

θ

JA

8-Lead LLP (NS Package # LDC08A)

Ordering Information

Order Number Size NSC Package

Drawing

LM2724AM SO-8 M08A 95 Units/Rail

LM2724AMX 2500 Units/Reel

LM2724ALD LDC08A LDC08A 1000 Units/Rail

LM2724ALDX 4500 Units/Reel

Pin Descriptions

Pin Name Function

1SW

2 HG Top gate drive output. Should be connected to the top FET gate.

3 BOOT

4 IN Accepts a logic control signal

5 SYNC Bottom gate enable

6V

CC

7LG

8 GND Ground

Top driver return. Should be connected to the common node of top
and bottom FETs

Bootstrap. Accepts a bootstrap voltage for powering the high-side
driver

Connect to +5V supply

Bottom gate drive output. Should be connected to the bottom FET
gate.

= 39˚C/W

θ

JA

Supplied As

20073506

www.national.com 2

Block Diagram

LM2724A

20073503

www.national.com3