L4974A

June 2000

3.5A SWITCHING REGULATOR

®

.

3.5A OUTPUT CURRENT

.

5.1V TO 40V OUTPUT VOLTAGE RANGE

.

0 TO 90% DUTY CYCLE RANGE

.

INTERNAL FEED-FORWARD LINE REG.

.

INTERNAL CURRENT LIMITING

.

PRECISE 5.1V

± 2% ON CHIP REFERENCE

.

RESET AND POWER FAIL FUNCTIONS

.

INPUT/OUTPUT SYNC PIN

.

UNDER VOLTAGE LOCK OUT WITH HYS-

TERETIC TURN-ON

.

PWM LATCH FOR SINGLE PULSE PER PE-

RIOD

.

VERY HIGH EFFICIENCY

.

SWITCHING FREQUENCY UP TO 200KHz

.

THERMAL SHUTDOWN

.

CONTINUOUS MODE OPERATION

DESCRIPTION

The L4974Ais a stepdownmonolithicpower switch-

ing regulator delivering 3.5A at a voltage variable

from 5.1 to 40V.

Realized with BCD mixed technology, the device

uses a DMOS output transistor to obtain very high

efficiency and very fast switching times. Features of

BLOCK DIAGRAM

POWERDI P (16+ 2+ 2)

the L4974A include reset and power fail for micro-

processors, feed forward line regulation, soft start,

limiting current and thermal protection. The device

is mounted in a Powerdip16 + 2 + 2 plastic package

and requires few external components. Efficient

operation at switching frequencies up to 200KHz

allows reductionin the size and cost of external filter

component.

ORDERING NUMBER : L4974A

1/22

This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

MULTIPOWER BCD TECHNOLOGY