TCAN1051G-Q1: CAN bus common mode choke

For 3.3V CAN, is the TCAN337DR is the equivalent of we want to use the Silent pin.

For the TCAN1051, max voltage on can bus is +/-15V, with absolute 18V.
I assume that means we need TVS diode to clamp max voltage of less than +/- 15 to be safe.

Is there TCAN transceiver of higher rating?

We try to convert 3.3V can bus to 5V can bus.
==can5--tx/rx--can3.3==

I'm not sure this would work. It might cause latch up issue.

The latchup issue I am thinking of :

An Rx of zero on the first transceiver will transmit a zero on the second transceiver which is expected .The Rx on the second transceiver however, will go low which will cause a Tx of zero on the first receiver, causing the Rx on the first receiver to go low.

I misread about voltage on AN1051GVDRQ1. It should be +/-58V fault tolerance or +/- 70V for H version so I'm ok with that.

The only concern I have is the latchup issue in the voltage conversion case.

Hi Khoi,

You are right that TCAN337 would be the functionally-equivalent 3.3-V alternative to TCAN1051. Note that the designs between these two are different, though, and so parameters like fault voltage tolerance will differ as well (I believe you noticed this already).

Your concern about a dominant level locking up a system that connects the TX/RX lines of two CAN transceivers together is valid. May I ask why you are trying to convert between 5-V CAN and 3.3-V CAN? Both TCAN1051 and TCAN337 would be able to interoperate with standard ISO 11898 high-speed CAN buses without requiring conversion.

If the conversion is necessary (e.g., due to EMC concerns, etc.), then external logic circuits could be used to control the individual transceivers' TX/RX lines appropriately to avoid lock-up. An example implementation is given here:

www.ti.com/.../TIDA-01487

Note that this specific design introduces isolation as well, but if that is not needed for your application it could be removed.

Regards,
Max

Currently we have a 3.3V can bus coming out of the device.
But we will need to convert to 5V can bus to connect to vehicle.
Maybe I need arbitration logic like the example.

OK, I read through the arbitration logic. Thanks for pointing it out.
We have to change the design so now we just need to tri-state the CAN_H/L Bus during power on reset time.