PIN CONNECTION (top view)

ABSOLUTE MAXIMUM RATINGS

Symbol

Parameter

Value

Unit

Transient Overvoltage :

Load Dump : 5ms

80

V

Current into Low Energy Clamping Zener

100

mA

Maximum Output Current

5.5

A

Junction and Storage Temperature Range

– 55 to + 150

°C

THERMAL DATA

Symbol

Parameter

Value

Unit

Thermal Resistance Junction-case

Max.

3

°C/W

DEVICE OPERATION

The alternator voltage, rectified by the auxiliary di-

ode trio, is compared with an external reference

and the resulting signal switches the output stage,

driving the alternator field coil.

As the regulator is a self-oscillating type, the

switching frequency depends on the whole sys-

tem parameter set (including the alternator char-

acteristics).

The regulator has an integrated filter in the volt-

age sensing path. Consequently it doesn’t need -

in the standard application- any external compo-

nent.

Anyway an external capacitor (0.1 - 1

µF) must be

the correct behaviour of the device when the rec-

tifying diodes feature very high switching spikes

that are not filtered by the devices.

This external capacitor must also be used when

the impedances of the cables connecting the al-

ternator to the battery are so high to cause a su-

perimposed ripple on the alternator voltage higher

than 3-4V.

The devices regulation voltage and the tempera-

ture coefficient may be independently set by

suited metal mask selections ; furthermore the

regulation voltage is trimmed within

± 1% of the

nominal value @ 25

°C.

The devices have an unique -and patented- sys-

tem to compensate the self-heating of the die due

to the power dissipated in the output stage. In this

way the internal reference voltage tracks the case

temperature rather than the die one.

The device can withstand the reverse battery and

the load dump (up to 80V) ; They can absorb, into

the internal clamping zeners, low energy spikes

up to a level of 100mA and its output is short cir-

cuit protected.

Finally the internal thermal shutdown avoids any

possible device damage due to overtemperature

problems.

L9444VB -L9448VB - L9480VB

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