L9705 Datasheet, PDF (1/8 Pages) STMicroelectronics – DOUBLE QUAD CONTACT INTERFACE CIRCUIT

L9705
DOUBLE QUAD CONTACT INTERFACE CIRCUIT
ADVANCE DATA
OPERATING DC SUPPLY VOLTAGE RANGE
5V TO 25V
SUPPLY OVERVOLTAGE PULSE UP TO 40V
VERY LOW STAND-BY QUIESCENT CUR-
RENT, MAX 50µA
INTERNAL CLAMPING DIODES AT CONTACT
INPUTS TO Vs AND gnd WITH PULSE CUR-
RENT CAPABILITY UP TO +50mA, -75mA
CHIP ENABLE FUNCTION AND TRISTATE
OUTPUTS FOR PARALLEL BUS CONNECTION
NOMINAL CONTACT CURRENTS OF 10mA
DEFINED WITH EXTERNAL CONTACT SE-
RIES RESISTORS RIN1-8
CONTACT STATUS MONITORING BY
MEANS OF COMPARING THE RESISTANCE
AT CONTACT SENSE INPUTS WITH THE IN-
TERNAL REFERENCE RESISTOR VALUE
RESISTANCE COMPARING WITH HYSTER-
ESIS FOR HIGH NOISE IMMUNITY AND IM-
MUNITY TO GROUND AND BATTERY PO-
TENTIAL DIFFERENCES
DIP 20
SO20L
ORDERING NUMBERS : L9705
DESCRIPTION
The L9705 is a bipolar monolithic integrated cir-
cuit for monitoring the status of up to four con-
tacts connected to GND and up to four contacts
connected to the battery. The contact sense input
supply the contact current and perform the con-
tact resistance comparison function.
At the output the contact status is translated into
a logical LOW level (contact closed) or logical
HIGh level (contact open).
BLOCK DIAGRAM
January 1992
1/8
This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.