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Original question:

TVS1801: ESD protect on CANH、CANL

TCAN332G: ESD/SURGE Protection for part with CANH/CANL voltage limit of 14V to -14V

hw wong
Prodigy 20 points
Part Number: TCAN332G
Other Parts Discussed in Thread: TCAN332, SN65HVD232, TCAN1042-Q1

Related to question asked by Shu-Cheng LIN on TCAN332 ESD/Surge protection (quoted below)

the TVS recommended for most CAN/CAN FD transceivers have Vbreakdown of 24-36V. This works for most transceivers as their CANH and CANL have Vmax/min of 40V/-40V.

For a CAN/CAN FD transceiver with CANH and CANL Vmax/min of 14V/-14V like the TCAN332, what is the recommended TVS protection device?

(I am sure the part recommended should be a "bi-directional" part but another pertinent issue is which part also have a Vbreakdown (breakdown voltage) that is NOT so high that by the time it starts working,

the TCAN332 would have been spoilt.

Mr. Lin's original query quoted below for everyone's easy reference:

TCAN332 specification 8.1 mentions that the maximum can withstand -14~+14V, then should I choose 14V two-way TVS?

  • 0
    TI__Guru 62910 points

    Hello,

    What level of transient immunity are you trying to achieve?  I ask because TCAN332 supports IEC 61000-4-2 ESD up to 12 kV (contact discharge) without use of any external protection circuits, and it would be a challenge to find a TVS diode that would have a working voltage range that supports +/- 12 V (the full common mode voltage range specified by the CAN physical layer) but a peak clamping voltage under stress less than 14 V.  If the application can work over a narrower voltage range (like 0 to 5 V, assuming all the nodes on the network share a solid ground connection), then it would be slightly easier but still difficult.  So, for higher transient immunity levels (>12 kV IEC ESD) it may be best to use a different transceiver like SN65HVD232 (if operation up to just 1 Mbps is acceptable) or TCAN1042-Q1 (if operation with VCC = 5 V is acceptable).

    Regards,
    Max

  • 0 in reply to Max Robertson
    Prodigy 20 points

    Hi Max,

    Thanks for the very prompt response. I understand the situation much more after your response.

    I actually posted because I was also wondering how I could find such a TVS diode myself but thought that it might be needed in as it is mentioned in the "TCAN33x dual-site industrial CAN evaluation module (EVM)" User Guide. See relevant section of the user guide below

  • 0 in reply to hw wong
    TI__Guru 62910 points

    Hello,

    Thanks for pointing that out - I understand the confusion.  Most applications do not require higher levels of immunity and so would not require a TVS; however, some may and so we wanted to make sure the PCB supported that as an option.  (Also, although this EVM is marketed for the TCAN33x family specifically it is designed to be used for any CAN transceiver device in 8-pin SOIC or SOT package.)

    Max