December 1999

L4620

LIQUID LEVEL ALARM

.

DRIVES DIRECTLY 300 mA ALARM LOAD

.

PROGRAMMABLE INPUT POLARITY TO

ACTIVATE THE OUTPUT STAGE

.

PROGRAMMABLE DELAY TIME

.

PROGRAMMABLE OUTPUT DUTY CYCLE

.

OUTPUT SHORT CIRCUIT PROTECTION

.

OVERVOLTAGE AND THERMAL

PROTECTION

DESCRIPTION

The L4620 is an integrated circuit, designed for the

liquid level control in automotive applications. The

liquid level is indicated by an attenuation between

transmitted and received signal across a sensor tip

in the lquid. If the attenuation exceedes an internal

threshold- sensortip outside the liquid or liquid tem-

peraturehigher than a determined value - a square-

wave alarm output indicates an unsufficient liquid

condition.If the liquid level is restoredbeforethe end

of a delay time the alarm is not activated.

Throughtwo pins it is possible to program : the delay

time to activate the alarm, the duty cycle of the

output squarewave, the polarity of the input thre-

shold of the sensor for alarm activation.

The above featuresmake theL4620particularlyver-

satile for many applications and give the possibility

to use various sensor types.

Internal circuits prevent spurious indications from

the liquid sensor and a latch keeps the alarm acti-

vateduntilthe supply voltageis switchedoff.The de-

vice includes thermal shutdown protections.

Minidip

ORDERING NUMBER : L4620

BLOCK DIAGRAM

®

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