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 Specifica-tion V3.0
  • Universal application: slaves, masters, repeaters, and bus-monitorsFloating 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


Title language Type Format File Size Date
Datasheets & Errata
star ASI4U Datasheet Datasheet PDF 1.06 MB
AS-Interface Evaluation Tools Feature Sheet Datasheet - Short-form PDF 174 KB
ASI4U Short-form Datasheet Datasheet - Short-form PDF 185 KB
User Guides & Manuals
Renesas CAD Altium Libraries for AID Products Rev 20210820 Guide 7Z 1.21 MB
AS-Interface Programmer V2.0 USB User Manual Manual - Development Tools PDF 1.50 MB
ASI4U Application Note - EEPROM Programming Manual - Development Tools PDF 248 KB
Application Notes & White Papers
AS-Interface Application Note - ASI4U and SAP5 Master Mode Application Note PDF 644 KB
PCN# : A1810-01 Change of Assembly Location on Select Devices Product Change Notice PDF 24 KB
AS-I Family Application Note - Electrical Inductor Schematic PDF 107 KB
ASI4U Release Note for Revision E Technical Brief PDF 342 KB


Title language Type Format File Size Date
AS-I Programmer Software Rev. 2.51 Software & Tools - Software ZIP 12.39 MB

memoryBoards & Kits

Part Number Title Type Company
ASI-PROG-KIT ASI Programmer Kit USB Development Renesas
ASI4UKIT Evaluation Board for ASI4U Evaluation Renesas