STMICROELECTRONICS L4957AD-3.3

L4957A
Up to 5A ULDO linear regulator
General features
■
1.5V, 1.8V, 2.5V and 3.3V fixed output voltage
■
3V to 14V input voltage range
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■
200mΩ RDS(on) typical @ tJ = 125°C
■
0.6V max. drop-out at 2A
■
Excellent load regulation
■
0.6mA quiescent current at any load
■
Short circuit protection
■
Thermal shutdown
The L4957AD devices are Ultra Low Drop Output
linear regulators with an internal N-channel
MOSFET of 200mΩ particulary suitable for low
voltage/low dropout applications.
■
Mother boards
■
Processor I/O & supplies
Operating with a input voltage from 3V to 14V
they are capable to deliver up to 5A.
■
Low voltage memory & chip set supplies
■
Graphic & sound cards
■
Low voltage logic supplies
■
Post regulator for SMPS
1
D2PAK
The devices are ideal for use as one of the
suppliesrequired by processor, for example they
are the cost effective and efficient solution for
conversion from 3.3V (rail bus) to 2.5V @ 2.5A or
to 1.5V with high current rating.
Fast response transient minimise the output
capacitor value. A minimum of 22µF assures the
stability in all load conditions.
The on-chip trimming technique offers a tighter
voltage reference tolerance (with ± 2% including
line and load variation) beside to ensure a
controlled short circuit current. Thermal shutdown
provides protection against overload conditions
that creates excessive junction temperature.
Part number
April 2006
Tube
Tape and Reel
L4957AD1.5
L4957AD1.5TR
L4957AD1.8
L4957AD1.8TR
L4957AD2.5
L4957AD2.5TR
L4957AD3.3
L4957AD3.3TR
Rev 6
1/12
www.st.com
12
Contents
L4957A
Contents
1
Block diagram and typical application . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3
2.1
Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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3.1
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2
Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2/12
L4957A
1
Block diagram and typical application
Block diagram and typical application
Figure 1.
VIN
10µF
Block diagram
IN
1
CHARGE
PUMP
CURRENT
LIMIT
VREF
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L4957AD
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+
PRE
REGULATOR
-
BUFFER
E/A
POWER
DMOS
200mΩ
OUT
THERMAL
SHUTDOWN
RX
3
VOUT
22µF
RY
2
GND
D00IN1108A
Figure 2.
Typical application
3V to 14V
C1
IN
3
1
VOUT
OUT
C2
2
GND
D00IN1107B
3/12
Pin description
L4957A
2
Pin description
2.1
Pin connection
Figure 3.
Pin connection (top view)
OUT
3
GND
2
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Pin description
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1
IN
D98IN933A
D2PAK
Table 1. Pin description
4/12
Name
Pin N°
Description
1
IN
2
GND
To connect to Ground to get 1.5V, 1.8V, 2.5V or 3.3V output.
3
OUT
Regulated output voltage. A minimum bypass capacitor of 22µF is required to
insure stability.
Unregulated input voltage; this pin must be bypassed with a capacitor larger
than 10µF.
L4957A
Maximum ratings
3
Maximum ratings
3.1
Absolute maximum ratings
Table 2. Absolute maximum ratings
Symbol
Parameter
Value
Unit
VIN
Supply input voltage
16
V
TJ
Junction temperature
-40 to +150
°C
TSTG
Storage temperature
-40 to +150
°C
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3.2
Thermal data
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Table 3. Thermal data
Symbol
Parameter
Value
Unit
RthJC
Maximum thermal resistance junction-case
3
°C/W
RthJA
Maximum thermal resistance junction-ambient
60
°C/W
Thermal Shutdown
Typ.
150
°C
Thermal Hysteresis
Typ.
29
°C
5/12
Electrical characteristics
4
L4957A
Electrical characteristics
Table 4. Electrical Characteristcs (TJ = 25°C, VIN = 5V, unless otherwise specified)
Symbol
Parameter
Test condition
VIN
Operating Supply
Voltage
VO
Output Voltage
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V
VIN = 3.3V ±5%; 0.1A < IO < 5A (1)
1.47
1.5
1.53
V
VIN = 3.3V ±5% IO = 0.1A
VIN = 5V ±5%
1.782
1.8
1.818
VIN = 3.3V ±5% (0.1A < IO< 4.5A) (1)
VIN = 5V ±5% 0.1A < IO< 5A
1.764
-O
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Current Limiting
IQ
Quiescent Current
3V < VIN< 14V (1)
Ripple Rejection
f = 120Hz, IO = 1A
VIN = 5V ∆VIN = 2V PP
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1. Specifications referred to TJ from 0°C to +125°C.
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2.45
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2.475
so
IO
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1.515
VIN = 5V ±5% 0.1A < IO< 5A (1)
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1.5
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Unit
1.485
VIN = 5V ±5% IO = 0.1A
uc
Max
3.15V < VIN < 5.25V; IO = 0.1A
VIN = 3.3V ±5% (0.1A < IO< 2.2A) (1)
VIN = 5V ±5% 0.1A < IO< 5A
Drain-Source ON
Resistance
Typ
3
VIN = 3.3V ±5% IO = 0.1A
VIN = 5V ±5%
RDS(on)
Min
1.8
1.836
2.5
2.525
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V
V
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V
2.5
2.55
V
3.267
3.3
3.333
V
3.234
3.3
3.366
V
300
mΩ
6.3
7.5
A
0.6
2
mA
o
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P
5.1
60
75
dB
L4957A
Electrical characteristics
Line regulation vs. junction
temperature
O u tp u t V o lta g e D e v ia tio n [m V ]
5
4 .5
3 V < V in < 6 .5 V
Io u t = 1 0 m A
4
3 .5
3
2 .5
2
Figure 5.
O u tp u t V o lta g e D e v ia tio n [m V ]
Figure 4.
Load regulation
5
4
V in = 5 V
T j = 2 5 °C
( P u ls e d te c h n iq u e h a s b e e n u s e d )
3
V o u t = 1 .5 V
2
1
0
-1
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1 .5
-2
1
-3
0 .5
-4
0
-4 0 -2 0
Figure 6.
0
20
40
-5
60 80 100 120 140 160
T j [° C ]
Maximum output current vs.
junction temperature
O u tp u t C u rre n t [A ]
10
9
0
1
2
3
Figure 7.
5
DC operating area
O u tp u t C u r re n t [A ]
8
V in > 2 .8 V
T j= 1 2 5 ° C
7
T c =2 5 ° C
P d m a x= 40 W
C u rre n t L im ita tio n
8
7
6
6
5
P o w e r D issip a tio n L im it
R d son
lim it
5
4
T c= 7 0°C
P dm a x= 22 W
4
3
4
Io u t [A ]
(V in -V o u t) > 2 V
p in 2 = G N D
3
D C O p e ra tin g A re a
2
2
1
1
0
-4 0 -2 0
0
20 40 60 80 100 120 140 160
T j [° C ]
* P u ls e d te c n iq u e h a s b e e n u s e d
0
0
1
2
3
4
5
(V in - V o u t) [V ]
6
7
8
7/12
Electrical characteristics
Figure 8.
L4957A
Ripple rejection vs. frequency Figure 9.
R ip p le R e je c tio n [d B ]
VOUT
(V)
100
90
V rip p le = 3 V p - p
Output voltage vs. output
current (VOUT = 1.5V)
D00IN1109
V r ip p le = 0 .5 V p -p
80
70
60
50
40
C in = 2 2 u F
C o u t= 2 2 u F
V o u t= 1 .5 V
V in m in = 3 V
Io u t= 5 A
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30
20
10
0
10
100
1k
F re q u e n c y [ H z ]
10k
10 0 k
Figure 10. Maximum output current vs.
junction temperature
Io [A ]
5
4 .5
T j = 2 5 °C
4
Tj = 125°C
3 .5
Tj = 100°C
3
2 .5
2
1 .5
1
m a x im u m R o n lim its
0 .5
0
8/12
0
0 .2 0 .4 0 .6 0 .8
1
1 .2 1 .4 1 .6 1 .8 2
∆ V = V in - V o
6.3
IOUT(A)
L4957A
5
Package mechanical data
Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a Lead-free second level interconnect . The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com
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9/12
Package mechanical data
L4957A
Table 5. D 2PAK Mechanical data
mm.
inch
Dim.
Min
Typ
Max
Min
Typ
Max
A
4.30
4.60
0.169
0.181
A1
2.49
2.69
0.098
0.106
A2
0.03
0.23
0.001
0.009
B
0.70
0.93
0.027
0.037
B2
1.25
C
0.45
0.60
0.017
0.024
C2
1.21
1.36
0.047
0.054
D
8.95
9.35
0.352
0.368
E
10.00
10.28
0.393
0.405
G
4.88
5.28
0.192
0.208
L
15.00
15.85
0.590
0.624
L2
1.27
1.40
0.050
0.055
L3
1.40
1.75
0.055
0.069
1.40
0.049
0.055
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V2
0.40
0°
Figure 11. Package dimensions
10/12
0.016
8°
0°
8°
L4957A
6
Revision history
Revision history
Table 6. Revision history
Date
Revision
Changes
12-Feb-2002
5
Removed the L4957AV part number and its references in the whole
document
20-Apr-2006
6
New template
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11/12
L4957A
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12/12