L4955 Datasheet, PDF (1/14 Pages) STMicroelectronics – 5A ULDO LINEAR REGULATORS FAMILY

®
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:
• VO = 1.26V
• INHIBIT (IQ = 120µA TYP.)
• 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.
TYPICAL APPLICATIONS
MULTIPOWER BCD TECHNOLOGY
HEPTAWATT
ORDERING
NUMBERS
L4955
L4955V3.3
L4955V5.1
OUTPUT
VOLTAGE
1.26V ADJ
3.3V
5.1V
VERSAWATT
(TO-220)
PACKAGE
HEPTAWATT
VERSAWATT
VERSAWATT
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 150mΩ of R_DSON.
It operates from a 4.5V minimum supply, with a
very low quiescent current irrespective of the
load; a minimum of 22µF 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.
V_IN
C1
INH PG
IN
3
1
6
OUT
7
L4955
24
ADJ
5
CL
GND
V_OUT
R1
C2
R2
D97IN589
V_IN
C1
IN
OUT
1
3
L4955VXXX
V_OUT
2
C2
GND
D97IN590
February 1999
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