Methodology to Predict EME Effects in CAN Bus Systems Using VHDL-AMS

The electromagnetic emissions (EME) of integrated circuits (ICs) are of increasing importance in the selection of automotive components. Although the IC is treated as the main cause for these emissions, the electrical environment, i.e., the application of an IC including the minimal circuitry on the application board and its layout, as well as the global connection terminals (i.e., supply pins and bus signals) representing the load of an IC are crucial in determining the emission behavior of the entire system. This paper provides application engineers information about different aspects related to the EME of a controller area network (CAN) bus system and how emissions are generated and transformed within the application environment. It presents a methodology to investigate and predict the effects by using Very High-Speed IC Hardware Description Language-Analog Mixed Signal (VHDL-AMS). The description focuses on the interaction between the CAN transceivers and the twisted pair transmission line connecting them. Both common mode and differential mode as well as mode conversion aspects are considered. It highlights the fact that EMEs from a CAN bus system highly depend on the application environment.