CAN Transceiver help

Discussion in 'General Electronics Chat' started by arduinoECU, Apr 24, 2014.

  1. arduinoECU

    Thread Starter New Member

    Apr 24, 2014
    Hi everyone:

    I am currently reading about how the Physical layer and bus of a CAN (Controller Area Network) is implemented. I have encounter some circuit symbols which I do not understand. I am attaching the pictures what I am looking at.

    I am looking at those traingles (are they amplifiers?) and the circles (are they inverters?).

    I understand that a triangle followed by a circle is a NOT gate. Because all the signals in CAN bus is digital, I would expect a NOT gate.
  2. w2aew


    Jan 3, 2012
    The symbols are buffers or line drivers that have a single-ended input and differential output.
  3. Papabravo


    Feb 24, 2006
    The CAN Physical layer is implemented as a quasi-differential signal with RESPECT TO A COMMON GROUND. I'm not yelling, but rather trying to emphasize that CAN is not a true differential signaling method which would be independent of the ground level at the two ends of the cable.

    You also need to understand that that any CAN device on the cable can override the recessive level on the cable by transmitting a dominant level. Given the length of a cable and the transmit dominant level and the receiver threshold and the position of the sample point you should be able to establish the maximum useable baud rate. This is NOT simple stuff and requires considerable thought and understanding to do an optimal system. Tell me what you are attempting and I will help you.