TCAN4551-Q1: Can you specify the crystal frequency range needed to achieve 8 Mbps?

Hi Praveena,

CAN and CAN FD bit timing is set by assigning an integer number of "Time Quantum" per bit period in two 2 "phases" where the sample point is the location between phase 1 and phase 2. 

The "minimum time quantum" is equal to a single clock cycle of the crystal, but a prescaler divider can be applied to use multiple clock cycles for a single time quantum when the bit rate is slow and the clock frequency is fast.

The minimum number of time quantum per bit period is 5, and therefore a 8Mbps bit rate would require a minimum clock frequency of 40MHz (8 x 5 = 40).

Ideally you would want more time quantum than the minimum to improve the bit sampling and reduce the possibility of bit errors and 80MHz is commonly used in 8Mbps applications, but the maximum clock frequency the TCAN4551-Q1 supports is 40MHz, so you only have 40MHz as an option.

Regards,

Jonathan