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[FAQ] My MCU uses 3.3V as the logic supply, do I need a 3.3V CAN transceiver?

Genius 15640 points

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Unless you are working with a 3.3V CAN bus, you do not need a 3.3V CAN transceiver. There is a difference between 3.3V CAN transceivers and CAN transceivers with the ability to accept 3.3V logic levels. 3.3V CAN transceivers use a 3.3V VCC supply voltage and are typically used in industrial applications. The CAN bus is referenced to 3.3V and thus the recessive and dominant voltages are different compared to a more typical 5V CAN transceiver. MCUs are only connected to the logic pins of a CAN transceiver, such as TXD, RXD,  and STB; they do not interface with the actual CAN bus. So, if your MCU uses a 3.3V logic supply, TI has CAN transceivers that can reference its logic pins to a 3.3V supply while still working on a 5V CAN bus. Our TCAN1042V and TCAN1051V are prime examples of these transceivers. Pin 5 is the VIO pin, and apply 3.3V to this pin on these transceivers will allow the RXD, TXD, and STB/S pins to use 3.3V logic levels. 

Eric Hackett

Texas Instruments | INT-TRX| Applications Engineer