L4976D データシートの表示（PDF） - STMicroelectronics

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L4976D

1A step down switching regulator

STMicroelectronics 

L4976

1A step down switching regulator

Features

■ Up to 1A step down converter

■ Operating input voltage from 8v to 55v

■ Precise 5.1V reference voltage

■ Output voltage adjustable from 0.5V to 50V

■ Switching frequency adjustable up to 300kHz

■ Voltage feedforward

■ Zero load current operation

■ Internal current limiting (pulse-bypulse

■ and hiccup mode)

■ Protection against feedback disconnection

■ Thermal shutdown

Figure 1. Typical application circuit

DIP8

SO16W

Description

The L4976 is a step down monolithic power

switching regulator delivering 1A at a voltage

between 3.3V and 50V (selected by a simple

external divider). Realized in BCD mixed

technology, the device uses an internal power D-

MOS transistor (with a typical Rds(ON) of 0.25Ω) to

obtain very high efficency and high switching

speed. A switching frequency up to 300KHz is

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 today’s applications. Features of this

new generations of DC-DC converter include

pulse-by-pulse current limit, hiccup mode for short

circuit protection, voltage feedforward regulation,

protection against feedback loop disconnection

and thermal shutdown. The device is available in

plastic dual in line, MINIDIP 8 for standard

assembly, and SO16W for SMD assembly.

Vi=8V to 55V

5

8

R1

20K

L4976

3

4

C1

C7

220µF 220nF

C2

2.7nF

2

7

16

63V

L1

260µH

(77120)

VO=3.3V/1A

R2

9.1K

C4

22nF

C6

100nF

D1

GI

SB360

C8

330µF

April 2007

Rev 7

1/17

www.st.com

17

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