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ISO1050: absolute maximum rating of differential voltage on BUS pin

Part Number: ISO1050
Other Parts Discussed in Thread: ISO1042

Hello,

Could you let me know the absolute maximum rating of differential voltage on BUS pin for ISO1050?

When we connect 24V to CANL, it will damage ISO1050. However, the maximum voltage range of CANH/L is -27V to 40V.

Thanks

Dongbao

  • Hi Dongbau,

    The abs max for differential voltage is not specified for the ISO1050 unfortunately - we only have single -ended pin ratings to ground in the datasheet.    Please note that differential voltages higher than 3V (per the CAN standard) are unusual. We do have high common-mode voltages supported  (-12 to +12V in normal operation).

    Back to your specific question, can you please share more details or a schematic/block diagram for this? Some of the questions we are interested in are as follows:

    1) How are you applying this stress to CANL, is it w.r.t GND2  ?

    2)  If an External voltage source is used, what is the current limit?

    3) what is CANH connected to when CANL is being stressed? is it floating or connected to CANL through a differential resistor?

    4)Is the chip powered-on? If so, what is the TXD pin doing at this time?

    Sorry for the multiple questions, but these are important to provide a correct answer since there can be multiple variables involved ( current limits, thermals etc).

    if you can provide these details please, then our team will follow-up on this next week. 

    Thank you,

    Abhi

  • Hi Dongbau,

    Hope you got the clarification you needed from the post above.

    BTW, we have just released the latest Isolated CAN, the ISO1042 - which can support +/- 70V .
    All the conditions stated above in my previous post still applies, except the limit is here.

    Do check out the new ISO1042 here: www.ti.com/.../ISO1042


    By the way, It's been a few weeks since we heard from you, so I'd like to retire this thread and mark my previous reply as "TI thinks resolved "for completeness. Of course we will still be here if you need further questions for follow-up! you can do so by clicking the "ask a related question" button or "ask a new question" button.

    Best regards,
    Abhi
  • Hi Abhi,

    Thanks for your feedback and sorry for the later reply.
    1. Yes, 24V is w.r.t GND2.
    2. Current limit is 1.5A
    3. CANH is connected to CANL through differential resistor.
    4. Yes, ISO1050 is powered on.

    Dongbao