TCAN1051GV-Q1: How to set the termination resistor network in multiple TCAN1051-Q1

Hello,

Typically you would use two termination resistances on the bus, one for each end of the network. Since the termination resistances combine in parallel, using more than two per network may result in an overall bus resistance that is too low.

Regards,

Max

Hi Max,

Do you mean adding two set of termination resistors on the bus, one close to the connector and one close to the end of their board? How about the resistance? should they double the resistance to make overall resistance 120ohm?

Can you provide a drawing for better understanding? 

Thank you.

Best Regards,

Wei-Hao

Hi Wei-Hao,

In a CAN network, termination should be placed at the end-nodes which are the greatest cable length away. The termination value of 120-ohms is used to match the cable impedance to reduce signal reflections. Using two 120-ohm termination resistors in the system will present a 60-ohm equivalent load to the transceivers. If more than two of these resistors are added, the equivalent load will become larger and the transceiver may be unable to drive a valid Dominant level on the bus. If termination resistors are not included at the end-nodes, signal reflections may cause distortion in the signal and corrupt the data on the bus. 

For more information on Line Terminations in a CAN network, please refer to this application report on Controller Area Network Physical Layer Requirements

Let me know if you have any more questions.
Regards,
Eric

Hi Eric,

Thanks for your explanation, Does that mean we should add two 240ohm termination resistors to make equivalent load to be 120ohm? or adding only 1 set is preferable for stable operation?

Best Regards,

Wei-Hao

Hi Eric,

Got it, it is much clear now. Really appreciated your detailed explanation.

Best Regards,

Wei-Hao