Datasheet L4957AV3.3, L4957AV2.5, L4957AV1.8, L4957AV1.5, L4957AD2.5 Datasheet (SGS Thomson Microelectronics)



L4957A

UP TO 5A ULDO LINEAR REGULATOR

PRODUCT PREVIEW

1.5V, 1.8V, 2.5V AND 3.3V FIXED OUTPUT
VOLTAGE

3V TO 14V INPUT VOLTAGERANGE
200mΩ RdsonTYPICAL @ T

j = 125°C

0.6V max. DROP-OUT AT 2A
EXCELLENTLOAD REGULATION

0.6mAQUIESCENTCURRENT AT ANYLOAD
SHORTCIRCUIT PROTECTION
THERMAL SHUTDOWN

APPLICATIONS

MOTHERBOARDS
PROCESSORI/O& SUPPLIES
LOW VOLTAGE MEMORY & CHIP SET SUP-

PLIES
GRAPHIC& SOUND CARDS
LOW VOLTAGELOGIC SUPPLIES
POST REGULATORFOR SMPS

DESCRIPTION

The L4957A devices are Ultra Low Drop Output
linear regulators with an internal N-channel MOS
of 200mΩ particulary suitable for low voltage/low
dropoutapplications.

Operating with a input voltage from 3V to 14V
they are capableto deliver up to5A.

The devices are ideal for use as one of the sup-

MULTIPOWER BCD TECHNOLOGY

3

1

D2PAKVersawatt TO-220

ORDERING NUMBERS:

L4957AV1.5 L4957AD1.5
L4957AV1.8 L4957AD1.8
L4957AV2.5 L4957AD2.5
L4957AV3.3 L4957AD3.3

plies required 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

1.5Vwith highcurrent rating.
Fast response transient minimise the output ca-

pacitor value. A minimum of 22µF assures the
stabilityin 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 excessivejunction temperature.

TYPICAL APPLICATION

3V to 14V

OUTIN

1

3

V

OUT

L4957A

C1

May 2000

This is preliminary information on a new product now in development. Details are subject to change without notice.

2

GND

D00IN1107A

C2

1/7

L4957A

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

IN

T

i

T

stg

PINSCONNECTION

SupplyInput Voltage 16 V
JunctionTemperature -40 to +150 °C
Storage Temperature -40 to +150 °C

Versawatt (TO220)

BLOCKDIAGRAM

V

IN

10µF

IN

1

3

2

1

PRE

REGULATOR

D98IN838B

V

REF

+

E/A

-

OUT

GND

IN

CURRENT

LIMIT

CHARGE

PUMP

BUFFER

THERMAL

SHUTDOWN

3

2

1

D2PAK

POWER

DMOS

200mΩ

R

X

GND

3

OUT

IN

D98IN933A

OUT

V

22µF

OUT

R

Y

2

GND

D00IN1108A

PIN FUNCTIONS

Pin N° Name Function

1 IN Unregulated input voltage; this pin must be bypassed with acapacitor larger than 10µF.
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 insurestability.

2/7

THERMALDATA

Symbol Parameter TO220 D2PAK Unit

R

th j-case

R

th j-amb

Thermal Resistance Junction-case Max. 2.5 3 °C/W
Thermal Resistance Junction-ambient Max. 50 60 °C/W
Thermal Shutdown Typ. 150 °C
Thermal Hysteresis Typ. 20 °C

ELECTRICAL CHARACTERISTICS (Tj=25°C, VIN= 5V, unlessotherwise specified).

•

= Specificationsreferred to TJfrom 0°Cto +125°C.

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

IN

V

O

DSON Drain-Source ON

R

I

O

I

Q

OperatingSupply Voltage 3 14 V
Output Voltage 3.15V < VIN< 5.25V;IO=0.1A 1.485 1.5 1.515 V

=3.3V±5%;0.1A< I

V

IN

=3.3V ±5% IO= 0.1A

V

IN

V

=5V±5%

IN

=3.3V ±5% (0.1A< IO< 45A)

V

IN

V

=5V±5% 0.1A< IO<5A

IN

V

=3.3V ±5% IO= 0.1A

IN

V

=5V±5%

IN

=3.3V ±5% (0.1A< IO<2.2A)

V

IN

V

=5V±5% 0.1A< IO<5A

IN

V

=5V±5% IO= 0.1A 3.267 3.3 3.333 V

IN

=5V±5% 0.1A< I

V

IN

<5A • 1.47 1.5 1.53 V

O

1.782 1.8 1.818 V

•

1.764 1.8 1.836 V

2.475 2.5 2.525 V

•

2.45 2.5 2.55 V

<5A • 3.234 3.3 3.366 V

O

•

300 mΩ

Resistance

Current Limiting • 5.1 6.3 7.5 A

Quiescent Current 3V < V
Ripple Rejection f = 120Hz, I

V

< 14V • 0.6 2 mA

IN

=1A

=5V∆VIN=2V

IN

O

PP

60 75 dB

L4957A

Figure1: Line Regulation vs. Junction

Temperature

5

4.5
4

3.5
3

2.5
2

Output Voltage Deviation [mV]

1.5
1

0.5
0

-40 -20 0 20 40 60 80 100 120 140 160

3V < Vin < 6.5V
Iout = 10mA

Tj[°C]

Figure2: Load Regulation

5
4
3
2
1
0

Output Voltage Deviation [mV]

-1

-2

-3

-4

-5
012345

(Pulsed technique has been used)

Vin = 5V
Tj = 25 °C

Vout= 1.5V

Iout [A]

3/7

L4957A

Figure 3: MaximumOutputCurrentvs.Junction

Temperatur e

Ou tpu t Curre nt [A ]

10

9
8
7
6
5
4
3
2

(Vin-Vou t) > 2V

pin 2 = GND

1
0

-40-20 0 20406080100120140160

*Pulsed te cniq ue has been used

Tj [°C]

Figure 5: Ripple Rejection vs. Frequency

Ripple Rejection [dB]

100

90
80
70
60
50
40
30
20
10

0

Cin=22uF
Cout=22uF
Vout=1.5V
Vinmin=3V

Io ut= 5 A

Vripple=3V p-p V ripple=0.5Vp-p

1k10 100 10k

F req uency [Hz]

100k

Figure4: DC Operating Area

Output Current [A]

8

Vin>2.8 V
Tj=1 25C Tc=2 5 °C

7
6

Rdson

limit

5
4
3
2
1
0

012345678

Current Lim itation

DC Operating Area

(Vin - Vout) [V]

Power Dissipation Limit

Tc=70°C
Pdmax= 22 W

Pdmax= 40 W

Figure6: Output Voltagevs. OutputCurrent.

OUT

= 1.5V)

(V

6.3

D00IN1109

I

OUT

(A)

V

OUT

(V)

Figure7: Maximum Output Current vs. Drop-Out

Voltage

Io [A]

5

4.5
4

3.5

3

2.5
2

1.5
1

0.5
0

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

ma ximum Ro n limits

4/7

Tj = 25°C

Tj = 125°C

Tj = 100°C

∆V=Vin-Vo

L4957A

DIM.

MIN. TYP. MAX. MIN. TYP. MAX.

A 4.40 4.60 0.173 0.181
C 1.23 1.32 0.048 0.051
D 2.40 2.72 0.094 0.107
E 0.49 0.70 0.019 0.027

F 0.61 0.88 0.024 0.034
F1 1.14 1.70 0.044 0.067
F2 1.14 1.70 0.044 0.067

G 4.95 5.15 0.194 0.203
G1 2.40 2.70 0.094 0.106
H2 10.0 10.4 0.393 0.409
L2 16.4 0.645
L4 13.0 14.0 0.511 0.551
L5 2.65 2.95 0.104 0.11
L6 15.25 15.75 0.600 0.620
L7 6.20 6.60 0.244 0.260
L9 3.50 3.93 0.137 0.154

M 2.6 0.102

Dia 3.75 3.85 0.147 0.151

mm inch

OUTLINE AND

MECHANICAL DATA

6

Versawatt (TO220)

M

TO220MEC

5/7

L4957A

DIMENSIONS

REF.

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 1.40 0.049 0.055

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

Millimeters Inches

Min. Typ. Max. Min. Typ. Max.

OUTLINE AND

MECHANICAL DATA

L3 1.40 1.75 0.055 0.069

R 0.40 0.016

V2 0° 8° 0° 8°

A

E

L2

L

L3

A1

B2

B

G

2.0 MIN.
FLATZONE

C2

C

A2

D2PAK

16.90

D

10.30

R

8.90

3.70

5.08

1.30

6/7

V2

L4957A

Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences
of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is
granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specification mentioned in this publication are
subject to changewithout notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products
are not authorized for useas critical components in life support devices or systems without express written approval of STMicroelectronics.

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