ST L4920, L4921 User Manual

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L4920



VERY LOWDROP ADJUSTABLE REGULATORS

.

VERYLOWDROP VOLTAGE

.ADJUSTABLE OUTPUT VOLTAGE FROM

1.25VTO 20V

.400mAOUTPUTCURRENT

.LOWQUIESCENTCURRENT

.REVERSEVOLTAGEPROTECTION

.+ 60/ − 60VTRANSIENTPEAK VOLTAGE

PROTECTION

.SHORTCIRCUIT PROTECTION WITH FOLD-

BACKCHARACTERISTICS

.THERMAL SHUT-DOWN

DES CRIPTION

The L4920and L4921 areadjustablevoltageregu­latorswitha verylowvoltagedrop(0.4Vtyp.at 0.4A

=25°C), low quiescent current and comprehen-

T

j

siveon-chip protection.
Thesedevicesareprotectedagainstloaddumpand
field decay transients, polarity reversal and over
heating.
A foldbackcurrentlimiterprotectsagainstloadshort
circuits.
Theoutputvoltageisadjustablethroughanexternal
dividerfrom1.25V to 20V.The minimumoperating
input voltageis 5.2V (T

=25°C).

J

L4921

Pen tawatt

Minidip (4 + 4)

ORDERINGNUMBERS : L4920 (Pentawatt)

L4921(Minidip)

These regulators are designed for automotive, in­dustrialand consumerapplicationswhere low con­sumptionisparticularlyimportant.
In batterybackupandstandbyapplicationsthelow
consumptionofthese devicesextendsbatterylife.

BLOCK DIAGRAM

June 2000

1/7

L4920/L4921

ABSOLUTE MAXIMUM RATINGS

Symbol Parameter Value Unit

DC Input Operating Voltage

V

i

DC Reverse Input Voltage
Transient Input Overvoltages:
Load Dump:

rise

10ms

≤

0.5

≥

Ω

5ms≤t

Fall timeconstant = 100ms

τ

f

R

SOURCE

Field Decay:

fall

10ms, R

≤

SOURCE

T

J,TSTG

5ms≤t

τ

Rise time constant = 33ms

f

Junction and Storage Temperature Range – 55 to 150

PIN CONNECTI ONS (top view)

≥10Ω

35 V

C

°

TEST AND APPLICATION CIRCUI T

C = 100µF is required for stability (ESR≤3Ωover T range)
R2 = 6.2KΩ.

THERMALDATA

Symbol Parameter Minidip

R

th j-amb

R

th j-pins

R

th j-case

Thermal Resistance Junction-ambient
Thermal Resistance Junction-pins
Thermal Resistance Junction-case

Max
Max
Max

80°C/W
15°C/W

(4 + 4)

–

Pentawatt

60°C/W

–

3.5 °C/W

2/7

L4920/L4921

ELECTRICALCHARACTERISTICS(forVI=14.4V,TJ=25°C,VO=5V,CO=100µF,unlessOtherwiseSpeci-

fied)

Symbol Parameter Test Condition Min. Typ. Max. Unit

Operating Input Voltage VO≥ 4.5V, IO= 400mA VO+0.7 26 V

V

I

V

< 4.5V, IO= 400mA 5.2 26 V

≤

O

1.20 1.25 1.30 V

≤ 400mA (*)

O

1 10 mV/V

400mA (*) V

≤

O

4.5V 3 15 mV/V

≥

O

0.05

0.2

0.4

0.4

0.7

V
V
V

V

∆V

∆

I

(* ) Foldbac k protection

Reference Voltage 5.2V < VI< 26V

REF

Line Regulation VO+1V<VI< 26V, VO≥ 4.5V

O

Load Regulation 5mA≤I

V

O

Dropout Voltage IO= 10mA

V

D

Quiescent Current IO= 0mA

I

Q

Maximal Output Current 800 mA

I

O

Short Circuit Output Current (*) 350 500 mA

OSC

V

REF

5mA ≤ I

= 5mA

I

O

= 150mA

I

O

= 400mA

I

O

+1V<VI<26V 0.8 2 mA

V

O

= 400mA (*)

I

O

V

+1V<VI<26V 65 90 mA

O

ELECTRICALCHARACTERISTICS (forVI=14.4V,–40≤ TJ≤ 125°C (note1),VO=5V,CO=100µF,unless
OtherwiseSpecified)

Symbol Parameter Test Condition Min. Typ. Max. Unit

Operating Input Voltage V

V

I

V

∆V

∆V

I

(*) Foldback protection.
Note : 1. Design limits are guaranteed (but not 100% production tested) over the indicated temperature and supply voltage

Reference Voltage 5.4V < VI< 26V 1.17 1.25 1.33 V

REF

Line Regulation VO+ 1.2V < VI< 26V, VO≥ 4.5V

O

Load Regulation 5mA ≤ IO≤ 400mA (*) VO≥ 4.5V 5 25 mV/V

O

Dropout Voltage IO= 150mA

V

D

Quiescent Current IO= 0mA

I

Q

Maximal Output Current 870 mA

I

O

Short Circuit Output Current (*) 230 500 mA

OSC

ranges. These limits are not used to calculate outgoing quality levels.

4.5V, I

≥

O

≤ VO< 4.5V, IO= 400mA 5.2 26 V

V

REF

= 400mA VO+0.9 26 V

O

2 15 mV/V

= 5mA

I

O

0.2

= 400mA

I

O

+ 1.2V < VI<26V 1,2 3 mA

V

O

= 400mA (*)

I

O

+ 1.2V < VI<26V 80 140 mA

V

O

0.4

0.4

0.7

V
V

3/7

L4920/L4921

Figure 1 :

Figure 3 :

OutputVoltagevs. Temperature.

QuiescentCurrentvs. OutputCurrent

=5V).

(V

o

Figure2 :

FoldbackCurrentLimiting.

APPLI CATI ON INFORMATIO N

1) TheL4920and L4921haveV
the outputvoltagecan beset downto V

mustbe greaterthan5.2V(Tj=25°C).

V

i

≅ 1.25V.Then

REF

REF

but

2) Astheregulatorreferencevoltage sourceworks
inclosedloop,thereferencevoltagemaychange
in foldbackcondition.

3) Forapplicationswith highV

, the total power

l

dissipation ofthedevice withrespectto the ther-

4/7

malresistanceof thepackagemaybe limiting. The
total powerdissipationis :

P

tot=Vilq

+(Vi-Vo)l

o

A typicalcurve giving the quiescentcurrent lqas a
functionof the outputcurrentl

is shownin fig.3.

o

L4920/L4921

DIM.

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

A 3.3 0.130

a1 0.7 0.028

B 1.39 1.65 0.055 0.065

B1 0.91 1.04 0.036 0.041

b 0.5 0.020

b1 0.38 0.5 0.015 0.020

D 9.8 0.386
E 8.8 0.346

e 2.54 0.100
e3 7.62 0.300
e4 7.62 0.300

F 7.1 0.280

I 4.8 0.189
L 3.3 0.130
Z 0.44 1.6 0.017 0.063

mm inch

OUTLINE AND

MECHANICAL DATA

PowerMinidip

5/7

L4920/L4921

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

6/7

L4920/L4921

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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