SGS Thomson Microelectronics L4957V2.5, L4957V1.5, L4957D2.5, L4957D1.5 Datasheet



L4957

UP TO 4A ULDO LINEAR REGULATOR

1.5V AND 2.5VFIXEDOUTPUT VOLTAGE
3V TO 6.5V INPUTVOLTAGERANGE
200mΩ RdsonTYPICAL @ T

j = 125°C

0.6V max. DROP-OUTAT 2A
EXCELLENTLOAD REGULATION

0.6mAQUIESCENTCURRENTAT ANYLOAD
SHORT CIRCUIT PROTECTIONWITH FOLD-

BACK
THERMALSHUTDOWN

APPLICATIONS

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

PLIES
GRAPHIC& SOUND CARDS
LOW VOLTAGELOGIC SUPPLIES
POSTREGULATOR FOR SMPS

DESCRIPTION

The L4957 devicesare Ultra LowDrop Output lin­ear regulators with an internal N-channel MOS of
200mΩ particulary suitable for low voltage/low
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.

MULTIPOWER BCD TECHNOLOGY

3

1

D2PAKVersawatt TO-220

ORDERING NUMBERS:

L4957V1.5 L4957D1.5
L4957V2.5 L4957D2.5

The devices are ideal for use as one of the sup­plies required by processor, for example they are
the cost effectiveand efficientsolution 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 ca-

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

TYPICALAPPLICATION

3V to 6.5V

February 2000

C1

V

=1.5V/2.5V

OUTIN

1

3

OUT

L4957

2

GND

D97IN657E

C2

1/7

L4957

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

IN

T

i

T

stg

PINS CONNECTION

Supply Input Voltage 7 V
Junction Temperature -40 to +150 °C
Storage Temperature -40 to +150 °C

Versawatt (TO220)

BLOCK DIAGRAM

V

IN

10µF

IN

1

3

2

1

D98IN838B

OUT

GND

IN

3

2

GND

1

OUT

IN

D98IN933A

D2PAK

CURRENT

V

REF

LIMIT
WITH

FOLDBACK

CHARGE

PUMP

2/7

PRE

REGULATOR

+

E/A

-

BUFFER

THERMAL

SHUTDOWN

GND

2

POWER

DMOS

150mΩ

R

X

R

Y

3

OUT

D98IN839C

V

22µF

OUT

PIN FUNCTIONS

Pin N° Name Function

1 IN Unregulated input voltage; this pin mustbe bypassed with a capacitor larger than 10µF.
2 GND To connect to Ground to get 1.5V or2.5V output.
3 OUT Regulated output voltage. A minimum bypass capacitor of 22µF is required to insurestability.

THERMAL DATA

Symbol Parameter TO220 D2PAK Unit

R

th j-case

R

th j-amb

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

L4957 - ELECTRICALCHARACTERISTICS (Tj=25°C, VIN=5V, unlessotherwise specified).

• =Specificationsreferred to T

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

IN

V

O

V

∆

DSON Drain-Source ON

R

I

O

I

Q

(1) GND connected to ground.

OperatingSupply Voltage
(1)

Output Voltage (1) ForL4957V1.5/D1.5

Load regulation (1) 0.1A < IO < 4A 2 10 mV

O

Resistance
Current Limiting 90% V
Short Circuit Current V
Quiescent Current 0.1A < IO<4A 3V<V
Ripple Rejection f = 120Hz,I

from0°Cto +125°C.

J

0.1A< I
3V < V

<4A; 3V< VIN<6.5V

O

<6.5V; 0.1A< I

IN

ForL4957V2.5/D2.5

0.1A< I
3V < V

O

V

IN

<4A; 3V< VIN<6.5V

O

<6.5V; 0.1A< IO<4A

IN

O

=0V • 1.8 A

O

=5V∆VIN=2V

=4A

3 6.5 V

<4A •

O

•

1.47

1.455

2.45

2.425

1.5

1.5

2.5

2.5

1.53

1.545

2.55

2.575

• 200 300 m

5.1 6.3 7.5 A

•

< 6.5V • 0.5 2 mA

IN

60 75 dB

PP

L4957

V
V

V
V

Ω

Figure 1: 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: LoadRegulation

5
4
3
2
1
0

Output VoltageDeviation [mV]

-1

-2

-3

-4

-5
012345

(Pulsed technique has been used)

Vin = 5V
Tj = 25 °C

Vout = 1.5V

Iout [A]

3/7

L4957

Figure3: MaximumOutputCurrentvs.Junction

Tempera ture

O utp ut C urre n t [A]

10

9
8
7
6
5
4
3
2

(Vin-Vout) > 2V

pin 2 = GND

1
0

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

*Pulsed tecnique has been used

Tj [°C]

Figure5: RippleRejection vs. Frequency

R ipple R ejection [dB]

100

90
80
70
60
50
40
30
20
10

0

Cin=2 2uF
Cout=22uF
Vout=1.5V
Vinmin=3V

Io u t= 5 A

Vripple=3Vp-p Vripple=0.5Vp-p

1k10 100 10k

F requen cy [H z]

100k

Figure4: DC OperatingArea

Output Current [A]

8

Vin>2.8V
Tj=125C Tc=25°C

7
6

Rdson

limit

5
4
3
2
1
0

012345678

Current Limitation

DC Operating Area

(Vin - Vout) [V]

P ow er D is s ipation Li m it

Tc=70 °C
Pdmax=22 W

Pdmax=40 W

Figure6: OutputVoltage vs. Output Current.

OUT =1.5V)

(V

V

OUT

(V)

1.8 6.3 I

D98IN846A

80% V

OUT

OUT

(A)

Figure 7: Maximum OutputCurrent 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

maximum Ron limits

4/7

Tj = 25°C

Tj = 125°C

Tj = 100°C

V=Vin-Vo

∆

L4957

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
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

0.116

OUTLINE AND

MECHANICAL DATA

Versawatt (TO220)

M

TO220MEC

5/7

L4957

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

L4957

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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 change without notice. This publicationsupersedes and replaces all information previously supplied. STMicroelectronics products
are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics.

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