This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

SN65HVD1040: suggest circuit and component

Part Number: SN65HVD1040

Hi sir

This is the client's circuit diagram for FSP

Do you have any suggest reference circuit diagram for SN65HVD1040  ?






  • Jeff,

    Specifically referring to the diagram in the datasheet, the following values are recommended:

    R1 - 1k
    R2 - 1k
    R3 - 10k
    R4 - not needed, but 1k is fine
    R5 - 60
    R6 - 60

    C1 - 10-50pF
    C2 - 4.7 - 10uF
    C3 - 0.1uF
    C4 - 0.01uF
    C5 - 10-200pF
    C6 - 4.7 - 100nF
    C7 - 10-200pF

    R1, R2, and R3 are all current-limiting resistors in case some kind of high-voltage spike occurs on those pins, they are not needed for the device to function correctly.

    C1 and C4 are filter capacitances for the digital signals.

    C2 and C3 are filter capacitors for the device power supply.

    R4 isn't needed and typically I've seen this pin shorted to the midpoint of the termination resistors (R5 and R6).

    R5 and R6 are the termination resistors for the SPLIT configuration, and these should be 60 ohms to add up to 120 ohms in series.

    C5 and C7 are filter capacitors for the CAN bus, and I've seen these range from 10pF to 200pF. It really depends on how many nodes are expected on the CAN bus. If too much is added as filter capacitance at each node, the CAN bus signals will degrade enough to not pass through the transceiver to the controller correctly.

    C6 is the filter capacitor for the SPLIT termination. The range for this is 4.7nF to 100nF.

    Referring to the customer's schematic, I would change R78 and R79 to 60 ohms, and R57 and R75 to 1k ohms. R78 and R79 will work at 51 ohms, but typically CAN cable characteristic impedance is 120 ohms, and the customer will want to match impedance as closely as possible to avoid signal reflections on the bus.

    Can the values of C77, C73, C70, C63, and C64 be confirmed?