• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 12 subscribers
  • Views 380 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

ISO3080: R output state is Lo constant

ISO3080: About the state of R out when VCC1 power up

Hiroaki Yuyama TED
Expert 1660 points
Part Number: ISO3080

Dear, support team.

We continue to support our customers with the issue of Rout constant LO on ISO3080 power up.
https://e2e.ti.com/support/isolation-group/isolation/f/isolation-forum/1135169/iso3080-r-output-state-is-lo-constant


When VCC1 is slow ramping up, can R out follow the input if I disable RE and enable it after the supply voltage rises?

Best Regards,
Hiroaki Yuyama

  • 0
    TI__Guru 55735 points

    Hi Yuyama-san,

    Thanks for reaching out.

    Yes, R output is going to output the state of the bus when RE\ is enabled and VCC1 is in normal operating range. When VCC1 is slowly ramping up, R will start working when VCC1 reaches device operating supply range.

    Let me know if this answers your question, thanks.


    Regards,
    Koteshwar Rao

  • 0 in reply to Koteshwar Rao
    Expert 1660 points

    Hi Rao-san
    Thank you for your reply.

    With ISO3080, when VCC2 starts up and VCC1 slowly ramps up to reach the operating voltage range, does the R output not follow the input and become fixed at LO?

    If the R output is constant LO, the R output will be constant LO from power-up of the power supply.
    Yellow = VCC1 3.3V
    Green = VCC2 5.0V
    Purple = R output
    e2e.ti.com/.../iso3080-r-output-state-is-lo-constant

    I asked you if the RE pin should be LO or open to avoid the R output of the ISO3080 going LO constant.

    Best Regards,
    Hiroaki Yuyama

  • 0 in reply to Hiroaki Yuyama TED
    TI__Guru 55735 points

    Hi Yuyama-san,

    Thank you for additional inputs.

    The explanation I provided earlier for a typical working sample. I understand now that your question is specifically in reference to the sample that had failed. If you see any further failed samples, we recommend that you do not continue to use those samples and instead return those samples to TI for further analysis.

    We do not expect you to see any further samples to have the behavior that you have observed on the failed samples. Hence, you shouldn't see any further issues. Let me know if you have any further questions, thanks.


    Regards,
    Koteshwar Rao