TCAN332G: Application questions about TCAN332GD

Hi Max,

As these are pretty general questions, I'll briefly address each of your questions and link to a few resources that will expand further. 

Are CANH and CANL differential signals? What's the typical/characteristic impedance of CANH and CANL?
Yes, CANH and CANL are differential and will be actively driven to different polarities during dominant periods (logic 0). However, unlike other differential signal standards, the recessive leve (logic 1) is passively driven and is characterized by CANH and CANL resting at the same common voltage level (typically Vcc/2).
Typical characteristic impedance for a CAN bus is 120-ohms.


For more information about the CAN physical standard, see the link below. 
Controller Area Network Physical Layer Requirements

For system-level termination design, termination resistors should ideally be valued the same as the cable's characteristic impedance (120-ohms) and placed at the two end-points of the system (two nodes which are furthest apart). Termination can be included on the cable itself or on the board which holds the CAN transceiver, such as shown in the figure below. If such a structure is not possible in the customer's design, let me know and I can help identify possible solutions.

Customer need to use 1 pc TCAN332 for 1 pair of CANH/CANL correct？
Only one transceiver is necessary for each CAN node. The transceiver will drive CANH and CANL according to the state of the TXD pin and will receive the state of the bus on the RXD pin. Note that whenever TXD is driven dominant (low), the bus will be driven dominant and cause RXD to also display dominant. Each node will require its own CAN transceiver to interface with the bus. This is also depicted on Figure 30 above. Let me know if I've misunderstood your question here.

Would you please suggest about ESD/EMC design for a CAN bus? 
The ESD protection included on the TCAN EVM is a good starting point for this. The EVM includes a TVS diode (D2) placed close to the board connectors and bus capacitors (C2, C7, typically valued between 10pF and 150pF) to smooth any transient edges. TVS diodes should be selected to have a clamping voltage above the operational voltage range of the signal it's protecting, but a lower clamping voltage than the absolute maximum voltage that can be sustained by the protected  For more information on ESD protection designs and a deeper look into higher-level surge protection, see the following Reference Design.
IEC 61000 ESD, EFT, and Surge Bus Protection for CAN Reference Design

I hope this information helps. Please let me know if you have any specific questions or would like clarification on anything from these sources.

Regards,
Eric Schott