Datasheet

L4974A
January 1995
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
TheL4974Ais a stepdownmonolithicpowerswitch-
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
efficiencyand veryfast switching times. Featuresof
BLOCK DIAGRAM
POWERDIP (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 mountedin a Powerdip 16+ 2 + 2 plastic package
and requires few external components. Efficient
operationat switching frequenciesup to 200KHzal-
lows reduction in 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