FUNCTIONAL DESCRIPTION

The L4947PD is a very low drop 5V/0.5A voltage

regulator provided with a reset function and there-

fore particularly suited to meet the requirements

of supplying the microprocessor systems used in

automotive and industrial applications.

The block diagram shows the basic structure of

the device : the reference, the error amplifier, the

driver, the power PNP, the protection and reset

functions.

The power stage is a Lateral PNP transistor

which allows a very low dropout voltage (typ.

°C, max. 750mV over the full

curve of the dropout voltage as a function of the

junction temperature is shown in Fig. 1 : that is

The current consumption of the device (quiescent

µF, ESR < 10Ω,

Symbol

Parameter

Test Conditions

Min.

Typ.

Max.

Unit

Output Voltage

Over Full T Range

°C

4.80

4.90

5.00

5.00

5.20

5.10

V

V

Operating Input Voltage

6

26

V

Line Regulation

550

mV

Load Regulation

15

60

mV

Dropout Voltage

°C

Over Full T Range

0.40

0.55

0.75

V

V

Quiescent Current

°C

5

6.5

110

10

13

180

mA

mA

mA

Temperature Output Voltage

Drift

– 0.5

mV/

°C

SVR

Supply Volt. Rej.

µF;

50

60

dB

Output Short Circuit Current

0.50

0.80

1.50

A

Reset Output Saturation Voltage

0.40

0.40

V

V

Reset Output Leakage Current

50

µA

Power On-Off Reset out Peak

Voltage

1K

0.65

1.0

V

Transition

4.75

Vo –

0.15

V

Transition

+ 0.05

0.04

V

Power ON-Off Hysteresis

0.05

V

Delay Comparator Threshold

Transition

3.65

4.00

4.35

V

Transition

3.20

3.55

3.90

V

Delay Comparator Hysteresis

0.45

V

Delay Capacitor Charging

Current

°C20

/

µA

Delay Capacitor Discharge

Voltage

0.55

1.20

V

Power on Reset Delay Time

°C

102030

ms

T

L4947PD

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