Datasheet L4937NPD Datasheet (SGS Thomson Microelectronics)



DUAL5V MULTIFUNCTIONVOLTAGE REGULATOR

.STANDBYOUTPUTVOLTAGEPRECISION5V

± 2%

.

OUTPUT2TRACKEDTOTHESTANDBYOUT­PUT

.

OUTPUT 2 DISABLE FUNCTION FOR
STANDBYMODE

.VERY LOW QUIESCENT CURRENT, LESS

THAN 260µA,INSTANDBYMODE

.OUTPUTCURRENTS: I

.

VERYLOWDROPOUT(max0.4V/0.6V)

=50mA,I02=500mA

01

.OPERATINGTRANSIENTSUPPLYVOLTAGE

UP TO 40V

.POWER-ON RESET CIRCUIT SENSING THE

STANDBYOUTPUTVOLTAGE

.POWER-ONRESET DELAY PULSEDEFINED

BY THE EXTERNALCAPACITOR

.

THERMALSHUTDOWNANDSHORTCIRCUIT
PROTECTIONS

L4 937N PD

PowerSO20

ORDERINGNUMBER: L4937NPD

DESCRIPTION

TheL4937NPDisa monolithicintegrateddualvolt­age regulators with two very low dropout outputs
andadditionalfunctionssuchaspower-onresetand
inputvoltagesense.Theyaredesignedfor supply­ing microcomputer controlled systems specially in
automotiveapplications.

PI N CONNEC TIO N

(top view)

GND

N.C.

GND

N.C.

CT
EN

N.C.

GND 10

1
2

V

S

V

S

3
4
5
6
7
8
9

D95AT162A

20
19
18
17
16
15
14
13
12
11

GND
N.C.
V

O2

N.C.
V

O1

GND
RESET
N.C.
N.C.
GND

June 2000

This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.

1/9

L4937NPD

BLOCK DIAGRAM

V

V

EN

S1

S2

1.23V

REFERENCE

RESET

REG1

REG2

2µ

2.0V

1.23V

V

O1

V

O2

CT
RES

GND

D95AT163

THERMAL DATA

Symbol Parameter Value Unit

2/9

R

thj-case

ThermalResistance Junction-Case Max. 1.5

C/W

°

L4937NPD

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

V

T

j,Tstg

I

EN

V

EN

V

RES

I

RES

P

The circuit is ESD protected according to MIL–STD–883C.

Note :

APPLI CATI ON CI R CUIT

DC Supply Voltage 28 V

S

TransientSupply Voltage(T < 1s) 40 V
Junctionand Storage TemperatureRange –55 to 150

Enable Input Current(V

EN

0.3V)

≤

Enable Input Voltage V

1

±

S

Reset OutputVoltage 20 V
Reset OutputCurrent 5 mA
Power Dissipation 875 mW

D

°

mA

C

V

S1

C

S

REFERENCE

V

S2

EN

1.23V

RESET

REG1

REG2

2µ

CS≥ 1µF;C01≥ 6µF;C02≥ 10µF, ESR < 10Ω at 10KHz

2.0V

1.23V

D95AT164

V

O1

V

O2

CT
RES

GND

C

O1

CT

3/9

L4937NPD

ELECTRICAL CHARACTERISTICS (VS= 14V; –40°C ≤ TJ≤ 125°C unlessotherwise specified)

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

V

V

O2-VO1

V

DP1

V

V

DP2

V

V

OL 1.2

V

OLO1

V

OLO2

I

LIM1

I

LIM2

I

QSB

I

Operating Supply Voltage 25 V

S

StandbyOutput Voltage

O1

Output Voltage 2 TrackingError

6V ≤ V
1mA≤I

6V≤V
5mA≤I

≤ 25V

S

O1

≤

S

O2

50mA

≤

25V

500mA

≤

4.90 5.00 5.10 V

–25 +25 mV

Enable= LOW

DropoutVoltage1 IO1= 10mA

Inputto OutputVoltage

IO1

I

= 50mA

O1

Vs = 4V, IO1= 35mA 0.4 V

0.1

0.2

Differencein Undervoltage
Condition

DropoutVoltage2 IO1 = 100mA

Inputto OutputVoltage

IO2

I

= 500mA

O1

Vs = 4.6V,IO1= 350mA 0.6 V

0.2

0.3

Differencein Undervoltage
Condition

LineRegulation

6V ≤ V

I

Load Regulation 1
Load Regulation 2

1mA≤I
5mA≤I

Current Limit 1 VO1= 4.5V

V

≤ 25V

S

= 1mA; IO2= 5mA

O1

50mA

≤

O1

500mA

≤

O2

= 0V(note1)

O1

55
25

100

50
Current Limit 2 VO2= 0V 550 1000 1700 mA
Quiescent Current StandbyMode

(output2 disabled)

Quiescent Current IO1= 50mA

Q

I

= 0.3mA;TJ< 100°C

O1

2.4V

V

≥

EN

V

= 14V

S

V

= 3.5V

S

I

= 500mA

O1

210
340

0.25

0.4

0.3

0.6

20 mV

25 mV
50 mV

200
100

290
850

30 mA

V
V

V
V

mA
mA

µ
µA

A

ENABLE

V

ENL

V

ENH

V

ENhyst

I

EN

4/9

EnableInputLOW Voltage

–0.3 1.5 V

(output2 active)
EnableInputHIGH Voltage 2.4 7 V
EnableHysteresis 30 75 200 mV
EnableInputCurrent 0V < VEN< 1.2V

2.5V < V

EN

<7V

–10–1–1.50–0.5

+1

µ
µ

A
A

L4937NPD

ELECTRICAL CHARACTERISTICS (continued)

RESET

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

V

t

RD

t

RR

V

I

LRES

V

CTh

V

CTh, hyst

Note : 1: Foldbackcharacteristic

ResetLow Threshold Voltage Vo1-0.4 4.7 Vo1-0.1 V

Rt

ResetThreshold Hysteresis 50 100 200 mV

Rth

ResetPulseDelay
ResetReactionTime CT= 100nF 1 10 50
ResetOutputLOW Voltage

RL

ResetOutputHIGH Leakage V
Delay Comparator Threshold 2.0 V
Delay Comparator Threshold

Hysteresis

= 100nF;tR> 100µs

C

T

= 10KΩtoV

R

RES

VS= 1.5V

=5V 1 µ

RES

01

55 100 180 ms

100 mV

0.4 V

µs

A

FUNCTI O NAL DES CRIPTIO N

TheL4937NDisbasedontheSGS-THOMSONMi­croelectronicsmodularvoltageregulatorapproach.
Several out-standing features and auxiliary func­tionsareprovidedto meettherequirementsof sup­plyingthemicroprocessorsystemsusedinautomo­tiveapplications.

Furthermorethe device is suitablealso in otherap­plications requiringtwostabilizedvoltages.

The modular approach allows other features and
functionsto berealized easilywhenrequired.

STANDBYREGULATOR
The standby regulator uses an Isolated Collector

Vertical PNP transistor as the regulating element.
This structureallows a verylow dropoutvoltageat
currentsup to 50mA. The dropoutoperationofthe
standby regulator is maintained down to 2V input
supplyvoltage.The output voltage is regulatedup
tothetransientinputsupplyvoltageof40V.Thisfea­tureavoidsfunctionalinterruptions whichcouldbe
generatedby overvoltagepulses.

Figure1 :

OutputVoltagevs. Input Voltage.

Thetypicalcurveof thestandbyoutputvoltageasa
functionof theinputsupplyvoltageisshowninfig.1.

The current consumption of the device (quiescent
current) is less than 260µA when output 2 is dis­abled(standbymode).The dropoutvoltageis con­trolledto reducethe quiescentcurrentpeak in the
undervoltage region and to improve the transient
responsein thisregion.

Thequiescentcurrentisshowninfig.2asafunction
of the supplyinputvoltage2.

OUTPUT2 VOLTAGE
Theoutput2regulatorusesthe same outputstruc-

tureasthestandbyregulator,butratedforanoutput
currentof500mA.

The output2 regulatorworks in trackingmode with
the standbyoutput voltage as a referencevoltage
when theoutput2.

The output 2 regulator can be switched off via the
Enableinput.

5/9

L4937NPD

Figure2 : QuiescentCurrent vs. SupplyVoltage.

400µ

200µ

Figure3 : ProgrammableOutput2 VoltagewithExternalResistors.

RESETCIRCUIT
Theblockcircuitdiagramoftheresetcircuitisshown

infig.4.Theresetcircuitsupervisesthestandbyout­put voltage.The reset threshold of 4.7V is defined
by the internal reference voltage and the standby
outputdivider.

The reset pulse delay time t
chargetime of an externalcapacitorC

x2V

C

T

=

t

RD

6/9

2µA

, is defined by the

RD

:

T

Thereactiontimeoftheresetcircuitdependsonthe
discharge time limitation of the reset capacitor C

and is proportionalto the valueof CT.
The reactiontime of the resetcircuit increasesthe

noiseimmunity.Infact,if thestandbyoutputvoltage
drops below the resetthresholdfor a time shorter
thanthereactiontime t

, noresetoutputvariation

RR

occurs. The nominal reset delay is generated for
standbyoutput voltage drops longer than the time
necessary for the complete dischargingof the ca­pacitorC
C

T

. This time is typically equal to 50µsif

T

=100nF.Thetypicalresetoutputwaveformsare

shownin fig.5.

T

L4937NPD

Figure4 :

BlockDiagramoftheResetCircuit.

Figure 5 : TypicalResetOutputWaveforms.

VOUT1

VRT +0.2V

VRT

1.5V

RESET

t

RD

VINPUT

VOUT1

t

RR

t

R

t

RD

D95AT216

7/9

L4937NPD

DIM.

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

mm inch

A 3.6 0.142

a1 0.1 0.3 0.004

0.012
a2 3.3 0.130
a3 0 0.1 0.000 0.004

b 0.4 0.53 0.016 0.021

c 0.23 0.32 0.009 0.013

D (1) 15.8 16 0.622 0.630

D1 9.4 9.8 0.370 0.386

E 13.9 14.5 0.547 0.570
e 1.27 0.050

e3 11.43 0.450

E1 (1) 10.9 11.1 0.429 0.437

E2 2.9

0.114

E3 5.8 6.2 0.228 0.244

G 0 0.1 0.000 0.004
H 15.5 15.9 0.610 0.626

h 1.1

0.043

L 0.8 1.1 0.031 0.043

N10°(max.)

S

8°(max.)

T 10 0.394

(1) ”Dand F” donot includemold flash or protrusions.

- Moldflash or protrusions shall notexceed 0.15mm (0.006”).

- Criticaldimensions: ”E”,”G” and ”a3”

OUTLINE AND

MECHANICAL DATA

JEDEC MO-166

PowerSO20

E2

hx

45

DETAIL B

BOTTOM VIEW

R

lead

a3

Gage Plane

E

DETAIL B

0.35

S

D1

a1

L

c

DETAIL A

slug

-C-

SEATING PLANE

GC

(COPLANARITY)

E3

NN

a2

A

b

DETAIL A

e3

H

D

T

1

e

1120

E1

10

PSO20MEC

8/9

L4937NPD

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 change without notice. This publication supersedes 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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