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L4973 Datasheet, PDF (1/27 Pages) STMicroelectronics – 3.5A step down switching regulator | |||
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L4973
3.5A step down switching regulator
Features
â Up to 3.5A step down converter
â Operating input voltage from 8V to 55V
â 3.3V and 5.1V (±1%) fixed output, and
adjustable outputs from:
â 0.5V to 50V (3.3 type)
â 5.1V to 50V (5.1 type)
â Frequency adjustable up to 300kHz
â Voltage feed forward
â Zero load current operation (min 1mA)
â Internal current limiting (pulse by pulse and
HICCUP mode)
â Precise 5.1V (1.5%) reference voltage
externally available
â Input/output synchronization function
â Inhibit for zero current consumption (100mA
typ. at VCC = 24V)
â Protection against feedback disconnection
â Thermal shutdown
â Output over voltage protection
â Soft start function
Figure 1. Internal schematic diagram
DIP-18 (12+3+3)
SO-20 (12+4+4)
Description
The L4973 is a step down monolithic power
switching regulator delivering 3.5A at fixed
voltages 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 uses an internal power D-MOS transistor
(with a typical RDS(on) of 0.15â¦) to obtain very
high efficiency 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
converter 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 consumption 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.
VCC (8V to 55V)
ROSC
CIN
C2
7
8
12
CBOOT
9
L4973
1
3
4,5,6,10
L1
2
13,14,15 16 17 11
VO(3.3V or 5.1V)
COSC
RCOMP
CSS
D1
CCOMP
COUT
May 2007
D97IN554A
Rev 17
1/27
www.st.com
27
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