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Original question:

SN65HVDA1040A: possibility of latch-up and hang-up

SN65HVDA1040A-Q1: CAN driver Latch-up issue

Arvind Munde
Prodigy 100 points
Part Number: SN65HVDA1040A-Q1

Hii, 

I am facing CAN driver Latch-up issue(Same like: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/522680/sn65hvda1040a-possibility-of-latch-up-and-hang-up) but in my design I have used SMAJ24CA TVS diode for ESD & Transient protection and ESD specification on CANH and CANL are 8kV and 16kV.  

So let me know TVS diode which will protect CAN driver from Latch-up and damage for 8kV and 16kV ESD.

Also let me know minimum CAN driver clamping voltage during ESD event without external TVS diode.

  • 0
    TI__Genius 15345 points

    Hi Arvind,

    We specify the ESD ratings of all our pins in the datasheet: 

    CANH and CANL are pins 7 and 6. So without any external protection the CANH and CANL pins can survive the specified ESD events above. Anything outside that range can permanently damage the device.

    We actually have a great app note on how to design TVS diodes in your system. This app note also goes over ESD protection on a CAN bus, I highly recommend reading through it.

    Now when it comes to the ESD ratings of your diode I think you are a little confused. This is a great FAQ that goes over ESD fundamentals and specifically the clamping voltage of a diode. In short, the IEC 61000-4-2 rating of a diode will only tell you what the diode itself can survive from an ESD event, it doesn't go over the details of what the downstream devices will have to face if there is an ESD event. You have to look at the clamping voltage of the diode and make sure that the CAN device can withstand that voltage. The FAQ I have linked above goes over this concept in detail.

    The SN65HVDA1040A-Q1 has a maximum bus fault protection of -27V to 40V. So as long as your protection diode can clamp the voltage below the maximum bus fault voltage you won't do permanent damage to the device.

    Best,

    Chris