October 2007 Rev 10 1/15
15
L5972D
2A switch step down switching regulator
Features
■ 2A internal switch
■ Operating input voltage from 4.4V to 36V
■ Output voltage adjustable from 1.235V to 35V
■ Low dropout operation: 100% duty cycle
■ 250kHz Internally fixed frequency
■ Voltage feedforward
■ Zero load current operation
■ Internal current limiting
■ Protection against feedback disconnection
■ Thermal shutdown
Applications
■ Consumer: STB, DVD, TV, VCR, car radio,
LCD monitors
■ Networking: XDSL, modems, DC-DC modules
■ Computer: printers, audio/graphic cards,
optical storage, hard disk drive
■ Industrial: changers, car battery, DC-DC
converters
Figure 1. Test application circuit
Description
The L5972D is a step down monolithic power
switching regulator with a minimum switch current
limit of 2A so it is able to deliver more than 1.5A
DC current to the load depending on the
application conditions.
The output voltage can be set from 1.235V to 35V.
The device uses an internal P-Channel D-MOS
transistor (with a typical Rdson of 250mΩ) as
switching element to minimize the size of the
external components.
An internal oscillator fixes the switching frequency
at 250kHz.
Having a minimum input voltage of 4.4V only, it is
particularly suitable for 5V bus, available in all
computer related applications.
Pulse by pulse current limit with the internal
frequency modulation offers an effective constant
current short circuit protection.
SO8
www.st.com
D03IN1436
8
2
4
5
1
7
L5972D
C1
10µF
35V
CERAMIC
C2
100µF
10V
VOUT=3.3V
VIN = 4.4V to 35V
R1
5.6K
R2
3.3K
R3
4.7K
C4
22nF
C3
220pF
3
L1 33µH
6
D1
STPS2L40U
COMP
VCC OUT
FB
GND
