ST L4904A User Manual

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DUAL5V REGULATOR WITH RESET

.

OUTPUTCURRENTS : I01=50mA

I

=100mA

02

.

FIXEDPRECISIONOUTPUTVOLTAGE

±

5V

2%

.

RESETFUNCTION CONTROLLED BY INPUT
VOLTAGEAND OUTPUT 1 VOLTAGE

.

RESET FUNCTION EXTERNALLY PRO­GRAMMABLETIMING

.

RESETOUTPUT LEVELRELATEDTO
OUTPUT2

.

OUTPUT 2 INTERNALLY SWITCHED WITH
ACTIVEDISCHARGING

.

LOW LEAKAGE CURRENT, LESS THAN 1µA
ATOUTPUT 1

.

LOWQUIESCENTCURRENT (Input 1)

.

INPUT OVERVOLTAGE PROTECTION UP TO
60V

.

RESETOUTPUT NORMALLY HIGH

.

OUTPUTTRANSISTORSSOAPROTECTION

.

SHORT CIRCUIT AND THERMAL OVER­LOADPROTECTION

Minidip

ORDERING NUMBER :

L4904A

L4904A

DESCRIPTION

The L4904A is a monolithic low drop dual 5V
regulatordesignedmainlyforsupplyingmicroproc­essorsystems.

Resetand data savefunctionsduring switchon/off
canbe realized.

PIN CONNECTION

June 2000

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L4904A

PIN FUNCTIONS

N°

1 Input 1 Low Quiescent Current 50mA Regulator Input.
2 Input 2 100mA Regulator Input.
3 Timing

4 GND Common Ground.
5 N.C. Not connected.
6 Reset

7 Output 2 5V – 100mA Regulator Output. Enabled if V
8 Output 1 5V – 50mA regulator output with low leakage in switch-OFF condition.

BLOCKDIAGRAM

Name Function

If Reg. 2 is switching-ON the delay capacitor is charged with a 10µA constant current. When

Capacitor

Reg. 2 is switched-OFF the delay capacitor is discharged.

When pin 3reaches 5V the reset output is switchedhigh.

Output

Therefore t

the C

capacitor is discharged.

o2

RD=Ct

5V

(

); tRD(ms) = Ct(nF).

10µA

1>VRTand V

o

IN 2>VIT

. If Reg. 2 is switched-OFF

SCHEMATIC DIAGRAM

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ABSOLUTEMAXIMUM RATINGS

Symbol Parameter Value Unit

V

IN

I

o

P

tot

T

DC Input Voltage
Transient Input Overvoltage (t = 40ms)

Output Current Internally Limited
Power Dissipation at T
Storage and Junction Temperature – 40 to 150

j

amb

=50°C

24
60

1W

THERMALDATA

Symbol Parameter Value Unit

R

th j-amb

Thermal ResistanceJunction-ambient Max 100

L4904A

V
V

°C

°C/W

ELECTRICAL CHARACTERISTICS

(V

IN

= 14.4V,T

=25oC unlessotherwise specified)

amb

Symbol Parameter Test Conditions Min. Typ. Max. Unit

V

DC Operating Input Voltage 20 V

i

V

Output Voltage1

01

V
V

V

V

∆V
∆
∆
∆

Output Voltage2 HIGH

02 H

Output Voltage2 LOW I02= – 5mA 0.1 V

02 L

I

Output Current 1 ∆

01

I

Leakage Output 1 Current

L01

I

Output Current 2 ∆

02

Output 1 Dropout Voltage (*) I01= 10mA

I01

V

Input Threshold Voltage V01+ 1.2 6.4 V01+ 1.7 V

IT

Input Threshold Voltage Hyst. 250 mV

ITH

Line Regulation 7V < VIN< 18V, I01= 5mA 5 50 mV

01

Line Regulation 2 7V < VIN< 18V, I02= 5mA 5 50 mV

V

02

Load Regulation 1 VIN= 8V, 5mA < I01< 50mA 5 20 mV

V

01

Load Regulation 2 VIN= 8V, 5mA < I02< 100mA 10 50 mV

V

02

IQ Quiescent Current

Quiescent Current 1 6.3V < V

I

Q1

V

V

V

V

∆V

∆

S
S

* The dropout voltage is defined as the differencebetween the input and the output voltage when the output voltage is lowered of 25 mV under
constant output current condition.

Reset Threshold Voltage V02–0.15 4.9 V02– 0.05 V

RT

Reset Threshold Hysteresis 30 50 80 mV

RTH

Reset Output Voltage HIGH

RH

Reset Output Voltage LOW IR= – 5mA 0.25 0.4 V

RL

t

Reset Pulse Delay Ct= 10nF 3 11 ms

RD

t

Timing Capacitor Discharge

d

Time

01

Thermal Drift

T

∆

V

02

Thermal Drift – 20°C≤<0>T

∆T

Supply Voltage Rejection f = 100Hz, VR= 0.5V, Io= 50mA 50 84 dB

VR1

Supply Voltage Rejection f = 100Hz, VR= 0.5V, Io= 100mA 50 80 dB

VR2

R Load 1kΩ
R Load 1kΩ

= – 100mV

V

01

=0,V01≤ 3V

V

IN

= – 100mV

V

02

= 50mA

I

01

I

02=I01

0<V
7V < V

I

01

I

R

5mA

≤

< 13V

IN

< 13V

IN

< 13V, V

IN1

≤ 5mA, I02=0

= 500µA

IN2

=0

Ct= 10nF 20

–20°C≤<0>T

amb

amb

≤ 125°C

125°C

≤

4.95 5.05 5.15 V

V01–0.1 5 V

01

50 mA

1

100 mA

0.7

0.75

4.5

1.6

0.8

0.9

6.5

3.5

0.6 0.9 mA

V

– 1 4.12 V

02

02

0.3

–0.8

0.3

– 0.8

V

µA

V
V

mA

V

µs

mV/°C

mV/°C

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