八路接触地面监控电路 OCTAL GROUND CONTACT MONITORING CIRCUIT
DESCRIPTION
The L9703isa bipolar monolithic integratedcir cuit for monitoring the status of up to eight contacts connected to GND.
It contains eight contact senseinputs and eight microcomputer compatible three-state outputs.
. OPERATING DC SUPPLY VOLTAGE RANGE 5V TO 25V
. SUPPLY OVERVOLTAGEPULSE UP TO 40V
. VERY LOW STANDBY QUIESCENT CURRENT 0.2mA
. INTERNAL CLAMPING DIODES AT CONTACT INPUTS TO VS AND GND
. INPUT PULSE CURRENT CAPABILITY UP TO + 50mA ; – 75mA
. NOMINAL CONTACT CURRENT OF 10mA DEFINED BY EXTERNAL CONTACT SERIES RESISTORS RI N1–8
. CONTACT STATUS MONITORING BY COMPARING THE RESISTANCE AT CONTACT SENSEINPUTS WITHTHE INTERNAL REFERENCE RESISTOR VALUE
. HIGHIMMUNITY DUE TO RESISTANCE COMPARISON WITH HYSTERESIS
