October 2007

Rev 10

1/15

15

L5972D

2A switch step down switching regulator

Features

Applications

LCD monitors

optical storage, hard disk drive

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 250m

Ω) 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

10

µF

35V

CERAMIC

C2

100

µF

10V

VOUT=3.3V

VIN = 4.4V to 35V

R1

5.6K

R2

3.3K

R3

4.7K

C4

22nF

C3

220pF

3

L1 33

µH

6

D1

STPS2L40U

COMP

VCC

OUT

FB

GND