ISO1050: ISO1050DUBR CAN noise question

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Replies: 1

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Part Number: ISO1050

Hi Support team

my customer encounters the problem of CAN noise. The waveform of the CAN from the communication line will be much worse than the board end. I would like to ask what kind of wire is generally used for CAN communication? Is there any problem with the following circuit diagram?

I would like to ask the general judgment of the quality of CAN noise. Generally speaking, it refers to the measurement of CANH-CANL, CANH-CANS, CANL-CANS?

application circuit

1 Reply

  • Hi Red,

    Thank you for posting to E2E! In CAN communication, the standard cable used has a characteristic impedance of 120Ω.

    Waveforms of CANH-CANS and CANL-CANS may be helpful for understanding where the noise originates although communication occurs over the CANH-CANL differential signal. Are there errors in data transmissions? Are the CANH and CANL waveforms above measured each with respect to CANS?

    Please share a connection diagram of the CAN bus this node is connected to. If there are numerous nodes on the bus, each does not need to have a termination resistance.

    Please also encourage our customer to use ISO1042 in this design over ISO1050. It is a new isolated-CAN device with higher isolation ratings, higher speeds, larger common mode range, and higher CANH and CANL standoff voltages of +/- 70V which may allow removal of the TVS protection diodes on this bus.


    Respectfully,
    Manuel Chavez