The ASI4U is a next-generation CMOS integrated circuit for AS-i networks. This low-level field bus AS i (Actuator Sensor Interface) was designed for easy, safe, and cost-effective interconnection of sensors, actuators, and switches. It transports both power and data over the same two-wire unshielded cable.

The ASI4U is used as part of a master or slave node and functions as an interface to the physical bus. It provides the power supply, physical data transfer, and communication protocol handling. The ASI4U is fully compliant with the AS-Interface Complete Specification V3.0. It is function and pin compatible with the A²SI IC.

All configuration data are stored in an internal EEPROM that can be easily programmed by a stationary or handheld programming device. The special AS-i safety option assures short response times for security-related events.


  • Compliant with AS-Interface Complete Specification V3.0
  • Universal application: slaves, masters, repeaters, and bus-monitors
  • Floating AS-i transmitter and receiver for highly symmetrical high-power applications
  • On-chip electronic inductor with current drive capability of 55 mA
  • Two configurable LED outputs to support all AS Interface Complete Specification V3.0 status indication modes
  • Several data pre-processing functions, including configurable data input filters and bit-selective data inverting
  • Additional addressing channel for easy wireless module setup
  • Support of 8 and 16 MHz crystals by automatic frequency detection
  • Special AS-i safety option
  • Clock watchdog for high system security




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