®
L4973V3.3 - L4973V5.1
L4973D3.3 - L4973D5.1
3.5A STEP DOWN SWITCHING REGULATOR
UPTO 3.5ASTEP DOWNCONVERTER
OPERATING INPUT VOLTAGE FROM 8V TO
55V
3.3V AND 5.1V (±1%) FIXED OUTPUT, AND
ADJUSTABLE OUTPUTS FROM:
0V TO 50V (3.3V type)
5.1V TO 50V (5.1 type)
FREQUENCY ADJUSTABLE UP TO 300KHz
VOLTAGE FEED FORWARD
ZERO LOAD CURRENT OPERATION (min
1mA)
INTERNAL CURRENT LIMITING (PULSE BY
PULSE AND HICCUP MODE)
PRECISE 5.1V (1.5%) REFERENCE VOLT-
AGE EXTERNALLY AVAILABLE
INPUT/OUTPUT SYNCHRONIZATION FUNC-
TION
INHIBIT FOR ZERO CURRENT CONSUMP-
TION (100µA Typ. at V
CC
= 24V)
PROTECTION AGAINST FEEDBACK DIS-
CONNECTION
THERMAL SHUTDOWN
OUTPUT OVERVOLTAGE PROTECTION
SOFT START FUNCTION
TYPICAL APPLICATION CIRCUIT (POWERDIP)
MULTIPOWER BCD TECHNOLOGY
POWERDIP (12+3+3)
SO20(12+4+4)
ORDERING NUMBERS:
L4973V3.3 (Powerdip)
L4973D3.3
(SO20)
L4973V5.1 (Powerdip)
L4973D5.1
(SO20)
DESCRIPTION
The L4973 is a step down monolithic power
switching regulator delivering 3.5A at fixed volt-
ages of 3.3V or 5.1V and using a simple external
divider output adjustable voltage up to 50V.
Realized in BCD mixed technology, the device
V
CC
(8V to 55V)
R
OSC
C
IN
C2
7
8
10 12
C
BOOT
V
O
(3.3V or 5.1V)
L1
1
4,5,6,
13,14,15 16
L4973
17
9
3
11 2
R
COMP
C
OSC
C
SS
C
COMP
D1
C
OUT
D97IN554A
April 2000
1/16
STMICROELECTRONICS [ STMICROELECTRONICS ]
