The CAN Physical-layer implementation is not defined by the Bosch CAN specification. However, it is defined in the ISO11898-2 standard. Here is an example of a Physical-layer tranceiver that connects to the bus: the Renesas HA13721 application specific standard product (ASSAP), which is a CAN transciever IC designed specifically for in-vehicle use. The HA13721 tranceiver is a standards-compliant high-speed design with Active and Standby operating modes. It features over temperature and over-current detection to help protect the system, provides good EMI performance, and has 3.3V-compatible Txd and mode input pins.