DESCRIPTION
The L9705 is a bipolar monolithic integrated circuit for monitoring the status of up to four contacts connected to GND and up to four contacts connected to the battery. The contact sense input supply the contact current and perform the contact resistance comparison function.
At the output the contact status is translated into a logical LOW level (contact closed) or logical HIGh level (contact open).

■ OPERATING DC SUPPLY VOLTAGE RANGE 5V TO 25V
■ SUPPLY OVERVOLTAGE PULSE UP TO 40V
■ VERY LOW STAND-BY QUIESCENT CURRENT, MAX 50µA
■ INTERNAL CLAMPING DIODES AT CONTACT INPUTS TO Vs AND gnd
   WITH PULSE CURRENT CAPABILITY UP TO +50mA, -75mA
■ CHIP ENABLE FUNCTION AND TRISTATE OUTPUTS FOR PARALLEL BUS CONNECTION
■ NOMINAL CONTACT CURRENTS OF 10mA DEFINED WITH EXTERNAL CONTACT
   SERIES RESISTORS RIN1-8
■ CONTACT STATUS MONITORING BY MEANS OF COMPARING THE RESISTANCE
   AT CONTACT SENSE INPUTS WITH THE INTERNAL REFERENCE RESISTOR VALUE
■ RESISTANCE COMPARING WITH HYSTERESIS FOR HIGH NOISE IMMUNITY AND
   IMMUNITY TO GROUND AND BATTERY POTENTIAL DIFFERENCES