I would like to change a 5V CAN transceiver on my board into a 3V3 CAN transceiver. Nevertheless as I am clearly not a specialist of the CAN protocol, I am afraid of doing a big mistake ! I think it will clearly make the communication less robust if I reduce the power supply to 3V3. The rate of error of communication will increase. In 5V I have already some errors.

Here are the two differents datasheet (If you know a better 3V3 CAN transceiver, I would be happy to hear it) :

3V3 transceiver : https://www.ti.com/lit/ds/symlink/sn65hvd232.pdf?ts=1591434105120&ref_url=https://www.ti.com/product/SN65HVD232

5V tranceiver : https://www.onsemi.com/pub/Collateral/AMIS-30660-D.PDF

Well what I see is the differential voltage and the common voltage between CANL and CANH is lower with a 3V3 tranceiver during the dominant and the recessive...

Transceiver 3V3 : enter image description here

Transceiver 5V :
enter image description here

Actually, according to the datasheet, the differential voltage is not really affected ? ! And the voltage refered to the ground is a bit affected but no much as I thoough... What do you think about the difference in robustness between the two transceiver ? What are the other elements to pay attention ?

Thank you very much and have a nice day !

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    \$\begingroup\$ If there are errors present on your existing bus, something is badly designed and needs to be fixed. You should resolve those errors before doing anything else. The usual suspects are missing signal ground, incorrect or missing termination or bad stub lengths. \$\endgroup\$ – Lundin Jun 8 at 11:05
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    \$\begingroup\$ As for SN65HVD232, I've been using it for many years and it works fine together with standard CAN. TI has a good application note/study somewhere explaining how it works even though the supply is 3V3, recommended reading. \$\endgroup\$ – Lundin Jun 8 at 11:07
  • \$\begingroup\$ Ok thank you very much for your comment :) \$\endgroup\$ – Jess Jun 8 at 14:57

The CAN specification requires that the differential voltage in the dominant state (with a load of two 120 Ω termination resistors) is nominally 2 V, at least 1.5 V, and at most 3 V. So the transceiver is not allowed to pull the signals completely to the rails.

The common-mode voltage of the output must be somewhere between 1.5 V and 3.5 V. The receivers must be able to handle ±12 V.

Both transceivers meet these specifications, and are equally robust. If you are getting errors, then something else is wrong. (But that would be a different question.)

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  • \$\begingroup\$ That's interesting really interesting ! I do not understand why the receiver should able to handle +- 12V if the common voltage is 3V5 and the differential voltage is 3V ? \$\endgroup\$ – Jess Jun 6 at 17:11
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    \$\begingroup\$ The receiver might not have the same ground. \$\endgroup\$ – CL. Jun 6 at 17:51
  • \$\begingroup\$ Thank you :)))) \$\endgroup\$ – Jess Jun 7 at 12:10

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