l4957 STMicroelectronics, l4957 Datasheet

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l4957

Manufacturer Part Number
l4957
Description
Up To 4a Uldo Linear Regulator
Manufacturer
STMicroelectronics
Datasheet

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l4957A
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l4957AD-1.8
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l4957AD-2.5
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APPLICATIONS
DESCRIPTION
The L4957 devices are Ultra Low Drop Output lin-
ear regulators with an internal N-channel MOS of
200m
dropout applications.
Operating with a input voltage from 3V to 6.5V
they are capable to deliver up to 4A at 1.5V or
2.5V fixed output voltages.
TYPICAL APPLICATION
February 2000
BACK
PLIES
1.5V AND 2.5V FIXED OUTPUT VOLTAGE
3V TO 6.5V INPUT VOLTAGE RANGE
200m Rdson TYPICAL @ T
0.6V max. DROP-OUT AT 2A
EXCELLENT LOAD REGULATION
0.6mA QUIESCENT CURRENT AT ANY LOAD
SHORT CIRCUIT PROTECTION WITH FOLD-
THERMAL SHUTDOWN
MOTHER BOARDS
PROCESSOR I/O & SUPPLIES
LOW VOLTAGE MEMORY & CHIP SET SUP-
GRAPHIC & SOUND CARDS
LOW VOLTAGE LOGIC SUPPLIES
POST REGULATOR FOR SMPS
particulary suitable for low voltage/low
3V to 6.5V
C1
j
= 125 C
IN
UP TO 4A ULDO LINEAR REGULATOR
1
L4957
2
GND
The devices are ideal for use as one of the sup-
plies required by processor, for example they are
the cost effective and efficient solution for conver-
sion from 3.3V (rail bus) to 2.5V @ 2.5A or to
1.5V with high current rating.
Fast response transient minimise the output ca-
pacitor value. A minimum of 22 F assures the
stability in all load conditions.
The on-chip trimming technique offers a tighter
voltage reference tolerance (with
line and load variation) beside to ensure a con-
trolled short circuit current. Thermal shutdown
provides protection against overload conditions
that creates excessive junction temperature.
3
OUT
Versawatt TO-220
MULTIPOWER BCD TECHNOLOGY
L4957V1.5
L4957V2.5
D97IN657E
ORDERING NUMBERS:
V
OUT
C2
=1.5V/2.5V
L4957D1.5
L4957D2.5
D
2
2% including
L4957
PAK
1
3
1/7

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l4957 Summary of contents

Page 1

... PLIES GRAPHIC & SOUND CARDS LOW VOLTAGE LOGIC SUPPLIES POST REGULATOR FOR SMPS DESCRIPTION The L4957 devices are Ultra Low Drop Output lin- ear regulators with an internal N-channel MOS of 200m particulary suitable for low voltage/low dropout applications. Operating with a input voltage from 3V to 6.5V they are capable to deliver ...

Page 2

... L4957 ABSOLUTE MAXIMUM RATINGS Symbol V Supply Input Voltage IN T Junction Temperature i T Storage Temperature stg PINS CONNECTION D98IN838B Versawatt (TO220) BLOCK DIAGRAM REF PRE REGULATOR 2/7 Parameter 3 OUT 2 GND IN 1 D2PAK CURRENT CHARGE LIMIT PUMP WITH FOLDBACK + BUFFER ...

Page 3

... Regulated output voltage. A minimum bypass capacitor required to insure stability. THERMAL DATA Symbol Parameter R Thermal Resistance Junction-case th j-case R Thermal Resistance Junction-ambient th j-amb Thermal Shutdown Thermal Hysteresis L4957 - ELECTRICAL CHARACTERISTICS (T = Specifications referred to T from +125 C. J Symbol Parameter V Operating Supply Voltage IN (1) V Output Voltage (1) For L4957V1 ...

Page 4

... L4957 Figure 3: Maximum Output Current vs. Junction Temperature O utput C urrent [ (Vin-Vout) > pin -40 - 100 120 140 160 ulsed tecnique ha s been used Figure 5: Ripple Rejection vs. Frequency ...

Page 5

... F 0.61 0.88 0.024 F1 1.14 1.70 0.044 F2 1.14 1.70 0.044 G 4.95 5.15 0.194 G1 2.40 2.70 0.094 H2 10.0 10.4 0.393 L2 16.4 0.645 L4 13.0 14.0 0.511 L5 2.65 2.95 0.104 L6 15.25 15.75 0.600 L7 6.20 6.60 0.244 L9 3.50 3.93 0.137 M 2.6 0.102 Dia 3.75 3.85 0.147 OUTLINE AND MAX. MECHANICAL DATA 0.181 0.051 0.107 0.027 0.034 0.067 0.067 0.203 0.106 0.409 0.551 0.116 0.620 0.260 0.154 Versawatt (TO220) 0.151 L4957 TO220MEC 5/7 ...

Page 6

... L4957 DIMENSIONS REF. Millimeters Inches Min. Typ. Max. Min. Typ. Max. A 4.30 4.60 0.169 A1 2.49 2.69 0.098 A2 0.03 0.23 0.001 B 0.70 0.93 0.027 B2 1.25 1.40 0.049 0.055 C 0.45 0.60 0.017 C2 1.21 1.36 0.047 D 8.95 9.35 0.352 E 10.00 10.28 0.393 G 4.88 5.28 0.192 L 15.00 15.85 0.590 L2 1.27 1.40 0.050 L3 1.40 1.75 0.055 R 0.40 0.016 2.0 MIN. FLAT ZONE 6/7 OUTLINE AND MECHANICAL DATA 0.181 0.106 ...

Page 7

... The ST logo is a registered trademark of STMicroelectronics 2000 STMicroelectronics – Printed in Italy – All Rights Reserved STMicroelectronics GROUP OF COMPANIES Australia - Brazil - China - Finland - France - Germany - Hong Kong - India - Italy - Japan - Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - U.S.A. http://www.st.com L4957 7/7 ...

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