Re: [EE} Protecting CAN bus

On Sat, Jun 28, 2025 at 6:37 PM Sean Breheny <[email protected]> wrote:
>
> There are specialized TVS diodes meant for use with CAN. One I've used
> before is the PESD1CAN,215 from Nexperian. They have lower than typical
> capacitance to avoid affecting the signal.
>
> I would put these TVSes on each node.
>
> Do you have termination resistors at each end of the cable?
>
> I assume that you have a "ground" reference wire in the cable as well to
> make sure that the common mode voltage at each node isn't too large?
>
> I would say that any time you have wires of significant length entering
> your house there should be lightning protection directly to a ground rod
> right before the point of entry to the house. This should probably be gas
> discharge tubes to be able to handle much greater current than TVSes. You
> would think that the risk would be non-existent since the wires are running
> close to the ground but that's not true. A lightning strike anywhere near
> those wires could cause momentary potential differences of thousands of
> volts between those lines and the local ground.
>
> Sean
>

I would second this.

GDT based Lightening barrier in the entry point.

CAN Bus protection TVS in each nodes.

Some references.
https://www.bourns.com/docs/technical-documents/technical-library/chip-diodes/application-notes/bourns_esd1712_canbus_application_brief.pdf
https://www.ti.com/lit/an/slvafc1/slvafc1.pdf


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Xiaofan

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