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TCAN1042-Q1: Measure the CANH by buffer

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Part Number: TCAN1042-Q1

Hi Team.

My customer now use TCAN1042 but they also want to measure CANH signal by a AMP? 

May I ask if customer add a Voltage Follower to measue the CANH on the CAN BUS, will it influence the CAN BUS data transfer?

  • Hi Amelie,

    In general this will not break communication, but you should be careful to consider the loading that the amplifier circuit introduces (i.e., due to its effective input impedance).  Leakage current into the amplifier circuit should be minimized as much as possible.

    Even with relatively low leakage, you may notice that the CANH/CANL voltage during recessive periods becomes skewed slightly higher or lower.  This is because the recessive level is only weakly biased by each receiver on the network.  CAN networks can tolerate these kinds of voltage shifts without losing communication, but when the recessive level is no longer centered between the CANH/CANL dominant voltages it could lead to higher emissions.  I'm not sure whether or not that is a key concern for this application, but I wanted to mention it just in case.

    Regards,
    Max

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