FAQ: Can I use a CAN2.0A/CAN2.0B transceiver to transmit CANFD frames with an FDCAN peripheral on STM32?
No. This is only possible if the communication bitrate does not exceed 1 Mb/s.
A CAN2.0A/B transceiver cannot pass through bitrates > 1 Mb/s and transmitting higher bitrates could lead to communication errors due to distortions in bits.
Find below an example from the SN65HVD23x transceiver datasheet.
This CAN transceiver is designed for data rates up to 1 Mb/s.