iCoupler? Isolation in CAN Bus Applications:The Controller Area Network (CAN) bus, a robust protocol designed for industrial applications, was originally developed for use in cars. It specifies a maximum cable length of 40 meters and up to 30 nodes. The flexibility and advantages of this specification have resulted in increased use in a wide range of applications.
Because the CAN bus system is typically used to connect multiple systems and is often run over very long distances, isolation between the bus and each system connection is critical. Isolation provides protection from overvoltage transients between the CAN bus cable network and the systems connected to it. Isolation also eliminates ground loops in the network, reduces signal distortion and errors, and provides protection from voltage/ground mismatches.
The intention of this application note is to give the user a brief overview of the CAN bus protocol, focusing on the system physical layer, as well as an understanding of why isolation is so important to the system. This application note also details how to implement isolation in a CAN bus system using Analog Devices’ iCoupler products.