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3.3 V Implementation of Isolated CAN FD Repeater Reference Design

Matt Child
Prodigy 100 points
Part Number: TIDA-01487
Other Parts Discussed in Thread: ISO7721, SN74HC32, SN74HC04

I wish to implement the CAN isolating part of the TIDA-01487 reference design (CAN1, Bus Arbitration Logic, Isolation, CAN2), but I am using a 3.3 V architecture.  From looking at the datasheets I believe the SN74HC04, AN74HC08, SN74HC32 and ISO7721 parts have recommended operating conditions which allow 3.3 V operation, however the CAN transcievers do not as they are 5 V supplied.

I have selected the SN65HVD231QD CAN transciever as a replacement for CAN1 and CAN2, which I believe will work fine - but is there something I have missed which will prevent these from working in this design?  My bus will be operating as 1 Mbps.

I am also interested if there is any information on what applications this reference design has previously been applied to?  My application is particularly affected by radiation and reliability requirements and as such being able to demonstrate previous design usage provides reassurance to the design.

Thanks

  • 0
    TI__Guru 74282 points

    Matt,

    Whether it's a 3.3V or 5V CAN transceiver, this repeater design will still work. The arbitration logic isn't based on voltage level, but just timing between the transceivers, so they will still work with 3.3V transceivers.

    From my experience, customers who request this don't usually use the isolation portion, they just need a design that gives them the ability to "extend" their CAN bus by using the repeater concept with the arbitration logic. Recently we've had several customers in the medical technology field reach out about this design, as well as some in PLC controllers. I'll reach out to the team who created this design to see if they have any other applications this has been used in.

    Please let me know if you have any other questions.

    Regards,

  • 0 in reply to Eric Hackett
    TI__Guru 74282 points

    Matt,

    I spoke with the team that created this board, and they let me know most of their requests come from factory automation, industrial transport, and automotive as well. 

    Regrds,