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SN65HVD230: Maximum CANH and CANL bypass capacitance for filters?

Part Number: SN65HVD230

Hi there, what is the maximum (or recommended) bypass cap values that CANH and CANL can withstand? (From CANH and CANL to GND). These capacitors are being used in conjunction with a downstream choke as a EMI filter for noise. I don't see a specification for it in the datasheet (or any other limiting factor). Can an FAE give me insight to the sizing requirements for C1/C2? They are currently a few nF:


  • Hi Oscar,

    Typical values for bus filtering capacitors are between 10pF and 150pF depending on the size of the network. Systems with more nodes should use smaller capacitor values to avoid overloading the bus with capacitance. Bus capacitors can be placed on the connector-side of the CMC to filter high frequency noise from the bus and slow transient edges. Placing capacitors on the transceiver-side of the CMC can cause excess ringing in some cases due to the more complex LRC relationship, but some designers prefer this arrangement to suppress any inductive kickback on the transceiver pins.

    Note that these are system-level recommendations and not requirements for the transceiver itself. Let me know if you have any other questions.

    Eric Schott