The datasheet says the MCP2561/MCP2562 is suitable for 12V and 24V systems except that everywhere I look in the datasheet it says VDD needs to be between 4.5 to 5V. How can CANH be greater than VDD or CANL be lower than VSS?? How would these internal MOSFETs work (shown on page 2 of datasheet) ?

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Looking at CANH and CANL also got me wondering what are CANH and CANL referenced to? For example if I want to have a 12V CANbus, how do I get those lines to 12V - how are they pulled up/down?

  • \$\begingroup\$ Does the CAN spec allow/require continued functioning, even if only one of the outputs is properly biased? \$\endgroup\$ – analogsystemsrf May 31 '19 at 3:37

I believe the suitability for 12/24V systems refers to the high DC voltage tolerance on the CAN lines, it is +/-58V absolute maximum for this part, meaning it will survive missing signal grounds better, when different CAN nodes get different voltage potentials. There's still plenty of quacks in the 24V market who design CAN systems without a signal ground.

But the part also has high ESD immunity, 14kV contact discharge, and automotive circuit stress test qualification etc.

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