ST L4922 User Manual

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VERY LOW DROPREGULATOR WITHRESET

.VERY LOW DROP (max. 0.9 V at 1 A) OVER

FULLOPERATINGTEMPERATURERANGE
(– 40 / + 125°C)

.LOW QUIESCENT CURRENT (max 70 mA at

1 A)OVERFULLT RANGE

.PRECISE OUTPUT VOLTAGE (5 V ± 4%)

OVERFULLT RANGE

.POWER ON-OFF INFORMATION WITH SET-

TABLEDELAY

.REVERSEBATTERYPROTECTION

.

SHORTCIRCUIT PROTECTION

.THERMALSHUTDOWN

DESCRIPTION

TheL4922isahighcurrentmonolithicvoltageregu­latorwith verylow voltagedrop (0.70V max at 1 A,

=25°C).

T

J

The device is internally protected against load
dumps transient of + 60V, reverse polarity, over-

L4922

Pentawatt

ORDERING N UM B E R : L4922

heatingandoutputshortcircuit :thankstotedforthe
automotiveand industrialapplications.

BLOCK DIAGRAM

June 2000

This is advanced informationona new product now in development or undergoing evaluation. Detailsare subjectto changewithout notice.

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L4922

ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

V

V

V

T

T

T

Note: T he circuit is ESD protected according to MIL-STD-883C

THERMAL DATA

Symbol Parameter Value Unit

R

th j-case

PIN CONNE CTIO N (Top view)

DC Input Voltage 35 V

i

DC Reverse Voltage –18 V

r

Positive Load Dump Protection (t = 300ms) 60 V

D

Junction Temperature Range –40 to 150 °

J

Operating Temperature Range –40 to 125 °

op

Storage Temperature Range –55 to 150

stg

Thermal Resistance Junction-case Max. 3.5

°

C
C
C

°

C/W

FUNCTI O NAL DESCRI PTION

The operatingprinciple of the voltage regulator is
basedonthereference,theerroramplifier,thedriver
and the power PNP. This stage uses an Isolated
CollectorVerticalPNPtransistorwhich allowsto ob­tainvery low dropoutvoltage(typ. 450mV)and low
quiescentcurrent(I

= 20mA typicallyatIo= 1A).

Q

Thanks to these featuresthe device is particularly
suited when the power dissipation must be limited
as,for example,in automotiveor industrialapplica­tionssuppliedby battery.

The three gain stages (operational amplifier,
driverand powerPNP) requiretheexternalcapaci­tor (Co

=22µF) to guaranteethe global stability

min

of the system.

2/6

Theantisaturationcircuitallowstoreducedrastically
the currentpeak whichtakes place during the start
up.

The reset function is LOW active when the output
voltagelevel islower than the resetthreshold volt­ageV
putvoltageis higherthanV

(typ.value:Vo–150mV).Whentheout-

RthOFF

theresetbecomes

RthON

HIGHafteradelaytimesettablewiththeexternalca­pacitorC

.Typicallytd=20ms,Cd=0.1µF.Thereset

d

and delay threshold hysteresis improve the noise
immunity allowing to avoid false switchings. The

typicalresetoutputwaveformis shownin fig. 1.

L4922

ELECTRICALCHARACTERISTICS

= 14. 4V, – 40°C ≤ TJ≤ + 125°C unlessotherwisespecified)

(V

i

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

i

V

o

V

∆

Line

SVR Supply Voltage Rejection I

V

∆

LOAD

V

i–Vo

I

q

I

SC

V

R

V

RT peak

Operating Input Voltage (*) Note 1 6 26 V
Output Voltage Io= 0mA to 1A

=25°C

T

J

4.8

4.9

5.2

5.1

Line Regulation Vi= 6 to 26V; IO= 10mA 5 25 mV

= 700mA

o

f = 120Hz; C
V

= 12Vdc+5V

i

=47µF

o

pp

55 dB

Load Regulation Io= 10mA to 1A 15 50 mV
Dropout Voltage

=25°C, IO=1A

T

J

Over Full T, I

Quiescent Current Io= 10mA

=1A

I

o

= 1A 0.90 V

o

0.45 0.70 V

7
25

12

70
Short Circuit Current 1.8 A
Rset Output Saturation Voltage 1.5V< VO<V

3V < V

O<VRT (off),IR

Power On-Off Reset out Peak

1KΩReset Pull-up to V

RT (off),IR

= 1.6mA

= 8mA

O

0.65 1.0 V

0.40

0.40

Voltage

50

V

RthOFF

I

R

Reset Output Leakage Current
(high level)

t

D

Reset Pulse Delay Time CD= 100nF 20 ms

Voin Regul.

=5V

V

R

Power OFF VoThreshold Vo@ Reset out H to L

Transition; T
–40°C≤T

I

C6

Delay Capacitor Charging

V4=3V 20

=25°C

J

≤+ 125°C

J

4.75

4.70

–0.15 V

V

o

Current (current generator)

V

RthON

V

4

Power ON VoThreshold Vo@ Reset out L to H

Transition

V

rthOFF

+ 0.03V

Delay Comparator Threshold Reset out = ”1” H to L Transition 3.2 3.8 V

V

o

0.04V

–

Reset out = ”0” L to H Transition 3.7 4 4.4 V

V

6H

Delay Comparator Hysteresis 500 mV

V
V

mA
mA

V
V

µ

V

µA

V

A

(*) Note 1 : The deviceis not operatingwithin the range: 26 V < Vi<37 V.

EXTERNALCOMPENSATION
Sincethepurposeofa voltageregulatoristosupply

a fixed output voltage in spite of supply and load
variations,theopen loopgain ofthe regulatormust
be veryhigh at lowfrequencies.Thismaycausein­stability as a result of the various poles presentin
the loop. To avoid this instability dominant pole
compensationis usedtoreducephaseshiftsdueto
other poles at the unity gain frequency.The lower
thefrequencyoftheseotherpoles,thegreatermust
be the capacitorused tocreate the dominantpole
for the same DC gain.

Where the output transistor is a lateral PNP type
thereis a polein the regulationloop at a frequency
toolow to be compensatedbya capacitorwichcan
be integrated.An external compensationis there­forenecessaryso a veryhigh valuecapacitormust
be connectedfrom theoutputto ground.
Theparassiticequivalentseriesresistanceoftheca­pacitorusedaddsa zeroto theregulationloop.This
zero may compromise the stability of the system
sinceits effecttendsto cancelthe effectofthe pole
added.In regulatorsthisESR mustbe lessthan3Ω
and theminimumcapacitorvalue is47µF.

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L4922

Figure1 : Typical ResetOutputWaveform.

Figure2 : TypicalApplicationCircuit.

(*) RECOMMENDED VALUE : C0=47µF, ESR < 10 ohm, (I

4/6

> 10 mA)OVER FULL T

out

range

.

L4922

DIM.

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

mm inch

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

E1 0.76 1.19 0.030 0.047

F 0.8 1.05 0.031 0.041

F1 1 1.4 0.039 0.055

G 3.2 3.4 3.6 0.126 0.134 0.142
G1 6.6 6.8 7 0.260 0.268 0.276
H2 10.4 0.409
H3 10.05 10.4 0.396 0.409

L 17.55 17.85 18.15 0.691 0.703 0.715
L1 15.55 15.75 15.95 0.612 0.620 0.628
L2 21.2 21.4 21.6 0.831 0.843 0.850
L3 22.3 22.5 22.7 0.878 0.886 0.894
L4 1.29 0.051
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
L9 0.2 0.008

M 4.23 4.5 4.75 0.167 0.177 0.187

M1 3.75 4 4.25 0.148 0.157 0.167

V4 40°(typ.)

OUTLINE AND

MECHANICAL DATA

Pentawatt V

A

H3

B

H1

L

L1
L8

VV

C

L5

Dia.

L7

L6

D1

V1

R

D

L2
L3

RESIN BETWEEN

V3

R

R

V4

F1

LEADS

H2

E

M1

M

V4

GG1

F

L9

VV

H2

F

E1

E

V4

5/6

L4922

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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