L4620 Datasheet, PDF (1/9 Pages) STMicroelectronics – LIQUID LEVEL ALARM

®
L4620
. 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 outsidethe liquid or liquid tem-
peraturehigher than a determinedvalue - a square-
wave alarm output indicates an unsufficient liquid
condition.If the liquid levelis restoredbeforethe end
of a delay time the alarm is not activated.
Throughtwo pins it is possible to program : the delay
BLOCK DIAGRAM
LIQUID LEVEL ALARM
Minidip
ORDERING NUMBER : L4620
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.
Theabovefeaturesmake 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.
December 1999
1/9