L4955

5A ULDO LINEAR REGULATORS FAMILY

UP TO 5A OUTPUT CURRENT

±2% PRECISE OUTPUT VOLTAGES

FAST TRANSIENT RESPONSE

0.75V TYP. DROP OUT VOLTAGE AT 5A

OPERATING INPUT VOLTAGE FROM 4.5V

ADJUSTABLE VERSION:

• POWER GOOD

• PROGRAMMABLE CURRENT LIMIT

• HEPTAWATT PACKAGE

FIXED VERSION:

• 3.3V, 5.1V OUTPUTS

• VERSAWATT PACKAGE

VERY LOW QUIESCENT CURRENT

SHORT CIRCUIT PROTECTION (Foldback

function)

THERMAL SHUTDOWN

APPLICATIONS

PENTIUM

™ AND POWER PC™ SUPPLIES

POST REGULATOR FOR SMPS

LOW COST SOLUTION FOR 5V TO 3.3V

CONVERSION

LOW COST BATTERY CHARGER

CONSTANT CURRENT REGULATOR

SUITABLE

FOR

APPLICATION

WITH

STANDBY FEATURE

DESCRIPTION

The L4955 is a family of monolithic ultra very low

drop linear regulators designed to supply the

most recent microprocessors.

The dropout voltage is only 0.75V (Typ.) at 5A, di-

rectly dependent on the output current conditions.

Realized in BCDII technology, it has on board a

charge pump to properly drive an N-channel

power mos Transistor with 150m

It operates from a 4.5V minimum supply, with a

very low quiescent current irrespective of the

load; a minimum of 22

µF output capacitor is re-

quired for stability.

The on-chip trimming techniques improve the pre-

cision of the available output voltages to

±2%.

Ancillary functions like power good, inhibit with

low power consumption, programmable output

voltage and current limiting make the flexible

heptawatt version usable in applications where

power management, stand-by, features, post

regulation and adjustable current generators for

battery chargers are important.

February 1999

®

TYPICAL APPLICATIONS

HEPTAWATT

VERSAWATT

(TO-220)

MULTIPOWER BCD TECHNOLOGY

ORDERING

NUMBERS

OUTPUT

VOLTAGE

PACKAGE

L4955

1.26V ADJ

HEPTAWATT

L4955V3.3

3.3V

VERSAWATT

L4955V5.1

5.1V

VERSAWATT

L4955

CL

GND

ADJ

OUT

IN

INH

PG

7

5

24

6

3

1

C1

R1

R2

C2

D97IN589

L4955VXXX

GND

OUT

IN

3

2

1

C1

C2

D97IN590

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