Datasheet L4956 Datasheet (SGS Thomson Microelectronics)

L4956

5A LOW DROP LINEAR REGULATOR

SPLITTED SUPPLY VOLTAGE FOR IM­PROVED EFFICIENCY:

-V

PW: 3V MIN. POWER SUPPLYVOLTAGE
SIG: 4.5VMIN.SIGNALSUPPLYVOLTAGE

-V
5A OUTPUTCURRENT
FASTLOAD TRANSIENT RESPONSE

0.75VTYP.DROPOUT VOLTAGE AT5A
INHIBITWITH ZEROCURRENT COMSUMPTION
POWERGOOD
SHORTCIRCUIT PROTECTION
THERMALSHUTDOWN
HEPTAWATTPACKAGE

APPLICATIONS

PENTIUM AND POWERPC SUPPLIES
LOW COST SOLUTION FOR 3.3V TO 1.5V

CONVERSION
SUITABLE FOR APPLICATIONS WITH

STAND BY FEATURE

DESCRIPTION

The L4956 is an adjustablemonolithiclinearregu­lator designedto satisfy very heavy load transient
and efficient power conversionfrom 3.3V to1.26V
and lower, up to 5A.

MULTIPOWER BCD TECHNOLOGY

HEPTAWATT

ORDERING NUMBER: L4956

Designed in BCDII technology, it uses a charge
pump techniqueto have a properinternal N-chan­nel gate drive. The signal supply voltage input

can operate from 4.5V up to an absoluteof

V

SIG

7V and the power supply voltage input V

PW

can
opearte from 3V min to an absolute of 7V. An
RDSON of 150mV gives a voltagedrop of 750mV
at 5A of loadcurrent.

Very fast load transients and ±1% of reference
voltage precision makes this device suitable for
supplying last micrprocessors generation and low
voltagelogics.

The Heptawatt package enriches the device with
auxiliaryfunctions like power good and inhibit.

TYPICALAPPLICATION

VPW=3.3Vbus

C

1

March 1998

V

SIG

5Vbus

INH PG

V

PW

=

V

SIG

C

3

36

1

2

L4956

4

GND

OUT

7

ADJ

5

D96IN374B

V

O

R

1

C

2

R

2

1/8

L4956

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

PW,VSIG

P

TOT

T

st,Ti

PIN CONNECTION(Top view)

Supply Input Voltage 7 V
ADJ pin

PG and INH pins
Power Dissipation @ T

Power Dissipation @ T

amb
case

=50°C

=90°C

-0.3 to 4

0toV

SIG

2

15

Storage Temperature -40 to +150 °C

7 OUT
6
5
4
3
2
1

PG
ADJ
GND
INH
V

SIG

V

PW

V
V

W
W

tab connected to pin 4

D96IN373

PIN FUNCTIONS

No. Name Function

1V
2V

Unregulated power input voltage; this pin must be bypassed witha capacitor larger than10µF.

PW

Unregulated signal input voltage this pin has to be by passed with a minimum capacitor of0.1µF.

SIG

3 INH TTL-CMOS input. A logic level on this input disable the device. An internal pull-down insures insures

full functionally even if the pin is open.
4 GND Ground.
5 ADJ The output is connected directly to this terminal for 1.26V operation via divider for higher voltages.
6 PG Opendrainoutput, this pin is low when theoutputvoltageis lowerthan 90%,otherwise ishigh.
7 OUT Regulated output voltage.A minimum bypass capacitor of 22µF is required to insure stability.

BLOCK DIAGRAM

V

V

SIG

INH

PW

1

2

REGULATOR

3

1.26V
INHIBIT

ACTIVE HIGH

PRE

V

REF

1.26V

=

+

E/A

-

CURRENT

LIMITATION

FOLDBACK

0.9V

REF

+

-

4

GND PG

CHARGE

BUFFER

THERMAL

SHUTDOWN

PUMP

6

POWER

DMOS

150mΩ

D96IN372A

OUT

7

R1 22µF

ADJ

5

R2

V

V

PW

10µF

SIG

V

OUT

2/8

THERMAL DATA

Symbol Parameter Value Unit

R

th j-pins

R

th j-amb

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

ELECTRICALCHARACTERISTICS (Tj=25°C,unless otherwisespecified)

Symbol Parameter Test Condition Min. Typ. Max. Unit

V

PW

V

SIG

V

OUT

∆V

OUT

∆V

OUT

I

O

I

Q

(1) Output voltage connected to ADJ.

PowerOperatingSupplyVoltage 3 6.5 V
Signal Operating Supply Voltage 4.5 6.5 V
Output Voltage (1) 0 < Tj < 125°C; VPW= 3.3V

4.5V< V
3V< V

0.1A < I

< 6.5V; 0.1A< IO<5A

SIG

<5.5V;4.5V< V

PW

< 5A; 0 < Tj< 125°C

O

SIG

<6.5V

Line regulation (1) 3V < VPW< 5.5V; IO= 10mA

4.5V< V

Load regulation (1) VPW = 3.3V; V

0.1A < I

Drop-out Voltage I

=5A

O

I

= 5A, Tj= 125°C

O

SIG

O

<6.5V

<5A

SIG

=5V

1.240 1.260 1.280 V

1.224 1.260 1.296 V

0.5 3 mV

15mV

0.75

1.1

1.1

1.5
Current Limiting 0 < Tj< 125°C 5.1 6.3 7.5 A
Short Circuit Current V
Quiescent Current at pin V

Stand By Current at pin V

SIG

SIG

= 0V, 0 < Tj< 125°C 1.8 A

O

0.1A < IO<5A

4.5V < V

SIG

<6.5V

INH = HIGH V

= 5V 100 150 µA

SIG

1.5 3 mA

Inhibit Threshold 0 < Tj < 125°C 1.1 1.26 1.42 V
Inhibit Histeresys 0.2 V
Inhibit Bias Sink Current 5 10 µA
Power Good Threshold 0.9x

V

OUT

Power Good Saturation I

= 4mA 0.1 0.4 V

6

Power Good Histeresys 0.2 V

L4956

V
V

V

3/8

L4956

Figure 1. DC Operating Area.

O utput C urrent [A]

8

Vpw > 3V
V sig > 4.5 V

7

Tj = 125°C

6
5
4
3
2

Rdson

limit

Cu r r e nt Lim ita tion

Tc = 70°C
Pdm ax=22 W

DC Operating Area

Power
Di ssi p ation
Limit

Tc = 25°C
Pdm ax = 40 W

1
0

012345678

(Vpw - Vout) [V]

Figure 3. Load Regulation.

5
4
3
2
1
0

-1

-2

-3

Output Voltage Deviation [m

-4

-5
012345

Pulsed tecnique has been used

Vpw = 3.3V
Vsig = 5V
Vout = Vadj
Tj = 25 °C

Iout [A]

Figure2. OutputVoltageStability vs.

Junction Temperature

Vout [V]

1.28

1.275

1.27

Vpw = 3.3V
Vsig = 5V
Iout = 10m A

1.265

1.26

1.255

1.25

1.245

1.24

-40 0 40 80 120 160
Tj [°C]

Figure4. DropoutVoltage.

1.25

1

Tj = 125 °C

0.75
Tj = 25 °C

0.5

Minimum Vpw - Vout Voltage [V]

0.25

Pulsed technique has been used

0

0123456

Iout [A]

Tj = -40 °C

Figure 5. MaximumOutput Current vs.

JunctionTemperature

Output Current [A]

10

4/8

9
8
7
6
5
4
3
2
1
0

-40

-20

Pulsed tecnique ha s been u sed

0

20

40

60

Tj [ºC]

(Vpw -Vout) > 2V

80

100

120

140

160

Figure6. QuiescentCurrent at pin VSIG vs.

Junction Temperature.

Iq [m A ]

2

SIG

V

1.8

1.6

1.4

1.2

0.8

0.6

0.4

1

-40

-20

0

20

40

=6.5V

Iout = 10 m A to 5A

3V<VPW<6.5V

80

60

Tj [°C]

100

120

14 0

160

L4956

Figure 7. QuiescentCurrent at pin VSIG vs.

Signal InputVoltage.

Iq [m A]

3

2.5

Io = 1 0 m A to 5A

Tj = 25°C

3V < VPW < 6.5V

2

1.5

1

0.5

0

01234567

VSIG [V]

Figure 9. Power Good Function

V

ADJ

0.9 V

ADJ

Figure8. Stand-ByCurrentatpinVSIGvs.Signal

InputVoltagewith INH= LOGICHIGH

Iq [µA]

150

125

100

75

Tj = 25°C

50

25

0

4 4 .5 5 5 .5 6 6 .5 7

V

OUT=VADJ

(R1+R2)/R2

hyst =200mV

3V < VPW < 6.5V

V S IG [V ]

Figure 10. Inhibit Function

Vref = 1.26V

PG

V

INH

Low

regulator

ON

High

regulator

OFF

Low

D96IN364B

hyst = 200mV

regulator

ON

t

t

t

D96IN365A

t

5/8

L4956

LOAD TRANSIENTRESPONSE
Figure 11.

Vout
50mV/div
CH1gnd

5A

0.5A
CH2gnd
Iout
2A/div

Figure 13.

Vout
50mV/div
CH1gnd

t=5µs/div

Figure 12.

Vout
50mV/div
CH1gnd

5A

0.5A
CH2gnd
Iout
2A/div

Test conditions:

PW

V

= 3.3V;V

SIG

from 0.5A to 5A;
dl

out

=20A/µs;Tj = 25°C

dt

=5;V

t=5µs/div

out

= 1.5V;Load Transient

5A

0.5A
CH2gnd
Iout
2A/div

t = 100µs/div

Figure 14. Load transient test circuit.

V

PW

1

V

=5V

C1,C2
470µF

Panasonic

HFQ

V

SIG

C16

220nF

SIG

2

GND

PG

6

L4956

43

INH

OUT

7

VOUT=1.5VVIN=3.3V

R4

ADJ

5

24Ω

R5

126Ω

C4 to

C9

100µF/10V

AVX TPS

6 each

D97IN593

C10 to

1µF

AVX

6 each

C15

X7R

6/8

HEPTAWATT PACKAGEMECHANICAL DATA

L4956

DIM.

A 4.8 0.189
C 1.37 0.054
D 2.4 2.8 0.094 0.110

D1 1.2 1.35 0.047 0.053

E 0.35 0.55 0.014 0.022
F 0.6 0.8 0.024 0.031

F1 0.9 0.035

G 2.41 2.54 2.67 0.095 0.100 0.105
G1 4.91 5.08 5.21 0.193 0.200 0.205
G2 7.49 7.62 7.8 0.295 0.300 0.307
H2 10.4 0.409
H3 10.05 10.4 0.396 0.409

L 16.97 0.668
L1 14.92 0.587
L2 21.54 0.848
L3 22.62 0.891
L5 2.6 3 0.102 0.118
L6 15.1 15.8 0.594 0.622
L7 6 6.6 0.236 0.260

M 2.8 0.110

M1 5.08 0.200

Dia 3.65 3.85 0.144 0.152

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

mm inch

7/8

L4956

Information furnished is believedto be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third partieswhich may result from its use. No
license is granted by implication or otherwise under any patent or patent rightsof SGS-THOMSON Microelectronics. Specificationmentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. SGS­THOMSON Microelectronics products are not authorizedfor use as critical components in life support devices or systems without express
written approval of SGS-THOMSON Microelectronics.

 1998 SGS-THOMSON Microelectronics– Printed inItaly – All RightsReserved

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