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TMDS361B - Propagation delay time, low to high (tPLH2) shorter than minimum value

Kawai
Guru 19785 points
Other Parts Discussed in Thread: TMDS361B

Hi Team,

Our customer is evaluating TMDS361B. On their board, they have shorter tPLH2 than the datasheet specification of 204ns (MIN).

[Q1]
What do you think is the reason why tPLH2 is < 204ns(MIN) ?

[Q2]
What happens if tPLH2 specification could not be met, outside the range of 204ns to 459ns ?

Thanks in advance.

Best Regards,

Kawai

  • 0
    TI__Mastermind 23815 points

    Hi Kawai-san,

    I think the reason for this shorter time may be differences in production yield variance or even materials.

    Having values outside of range are not critical, when Tphl or Tplh aproaches zero, it means the signal is propagating similar to no having TMDS361B.

    Having large values for Tphl or Tplh would translate to longer times to make connection.

    Having output signal fall times out of range may be a problem.

    Having propagation delays times between SCL and SDA may lead to problems too. I case you have problems with this times please check setup and hold time ranges.

    Regads

  • 0 in reply to Moises Garcia
    Guru 19785 points
    Hi Moises-san,

    Thank you for your comment.

    So can you say that even if tPLH2 is out of spec (< 204ns), customer could continue using this design without any problem ?

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Mastermind 23815 points
    Hi Kawai-san,

    Yes, they can continue designing without any problem, if they have any other timing parameter out of range please contact us again.

    Regards
  • 0 in reply to Moises Garcia
    Guru 19785 points
    Hi Moises-san,

    Thank you !!
    Please let me ask you again when we need your help.

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    Guru 19785 points
    Hello Moises-san,

    Please allow me to confirm one thing about this spec.

    The customer measurement is out of the datasheet spec. If this is from production yield variance or materials, I believe this device is a failure part, isn't it ?

    How should we/customer think about this result ??

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Mastermind 23815 points
    Hi Kawai-san,

    Production yield variance may be one of the reasons, but because of I²C protocol this small time may come from a small capacitance in that pin.
    If it comes from yield production, I wouldn't say it is a defective part because it doesn't malfunction, it just have a value outside of expected range, perhaps having a greater time outside of range may lead to a malfunction. However this small would indicate the current in such pin is higher than expected having a very little more power consumption.

    You may think of it as a defective part because it is out of range, I would say it is just not expected but better.

    Regards
  • 0 in reply to Moises Garcia
    Guru 19785 points
    Hi Moises-san,

    Thank you for your detailed explanation.

    Best Regards,
    Kawai