L4973 STMicroelectronics, L4973 Datasheet - Page 2

• Manufacturer Part Number: L4973
• Description: 3.5A STEP DOWN SWITCHING REGULATOR
• Manufacturer: STMicroelectronics

L4973V3.3 - L4973V5.1 - L4973D3.3 - L4973D5.1
uses an internal power D-MOS transistor (with a
typical Rdson of 0.15ohm) to obtain very high effi-
ciency and very fast switching times.
Switching frequency up to 300KHz are achievable
(the maximum power dissipation of the packages
must be observed).
A wide input voltage range between 8V to 55V
and output voltages regulated from 3.3V to 40V
cover the majority of the today applications.
Features of this new generation of DC-DC con-
PIN CONNECTIONS (Top view )
BLOCK DIAGRAM
2/16
COMP
SYNC
VFB
SS
BOOT
GND
GND
GND
OSC
OUT
OUT
V
V
CC
CC
Pin x = Powerdip
Pin (x) = S020
5.1V
3.3V
17(19)
11(12)
12(13)
18(20)
POWERDIP (12+3+3)
ZERO CURRENT
10(11)
1
2
3
4
5
6
7
8
9
INHIBIT
+
-
INH
E/A
D94IN162A
OSCILLATOR
OSC
START
18
17
16
15
14
13
12
11
10
SOFT
1(1)
SHUTDOWN
GOOD
THERMAL
VREF
+
-
PWM
SYNC
SS
V5.1
GND
GND
GND
VFB
COMP
INH
5.1V
3.3V
(4,5,6,7,14,15,16,17)
4,5,6,13,14,15
HICCUP CURRENT
GND
CURRENT
LIMITING
LIMITING
REFERENCE
INTERNAL
16(18)
verter includes pulse by pulse current limit, hiccup
mode for output short circuit protection, voltage
feed forward regulation, soft start, input/output
synchronization, protection against feedback loop
disconnection, inhibit for zero current consump-
tion and thermal shutdown.
Packages available are in plastic dual in line, DIP-
18 (12+3+3) for standard assembly, and SO20
(12+4+4) for SMD assembly.
R
S
V5.1
Q
Q
BOOT
GND
GND
GND
GND
OSC
OUT
OUT
INTERNAL
V
V
SUPPLY
CC
CC
7(8)
V
1
2
3
4
5
6
7
8
9
10
CC
OUT
SO20 (12+4+4)
DRIVER
5.1V
2(2)
D94IN163A
8(9)
OUT
V
CC
3(3)
CHARGE
CBOOT
20
19
18
17
16
15
14
13
12
11
9(10)
D94IN161B
SYNC
SS
V5.1
GND
GND
GND
GND
VFB
COMP
INH
BOOT