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

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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

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