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ISO1050: ISOLATED CAN

Dibin C T
Prodigy 40 points
Part Number: ISO1050

what is the use of Bus Bias(vcc/2) in the CAN_H and CAN_L Pins.
Is it necessary to connect CAN bus to VCC/2. How to connect this bus for normal operations?

  • 0
    TI__Mastermind 29595 points

    Hello Dibin,

    Thank you for reaching out. CAN is a differential protocol. The CANH and CANL signals are inverse of each other. The CANL signal goes from 0V to +2.5V and CANH goes from +2.5V to 5V. When the bus is driven to a "dominant" state (logic '1'), CAN L is 0V and CANH is 5V. In the "recessive" state (logic '0') both lines will be +2.5V (Vcc/2). This is a behavior that is the result of the CAN transceiver's design.

    There is no need to connect the CAN Bus pins to Vcc/2. The Bus Bias is part of the CAN physical layer standard. See the below screen shot.

    Please see Introduction to the Controller Area Network (CAN) (Rev. B) for more information.

    Let me know if this answers your question or if I have misunderstood. 

    Best,
    Andrew