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TCA9543A: FAST mode timing spec check

Will Wang47
Expert 8080 points
Part Number: TCA9543A


Hi team,

Customer is using TCA9543A in their product, and they get one question about the fast mode I2C input rise time and fall time. Now their test shows that the rise/fall time is ~8ns, which is smaller than the requirement, could you help check if this will be OK? And what will happen if they didn't meet the 20ns min spec requirement? Thanks.

Thanks and Best Regards,

Will

  • 0
    TI__Prodigy 380 points

    Hello Will,
    The table in the datasheet is meant to reflect the I2C standard and is only a system level specification not a device specification. The TCA9543A does not take into consideration the fall time, however fast fall times can sometimes contribute to undershoots which can cause device failure. Can you verify if the customer is not seeing undershoots?

    Regards,

    Rosemary 

  • 0 in reply to Rosemary Sanchez
    TI__Expert 8080 points

    Hi Rosemary,

    Thanks for your feedback. Customer didn't see any overshoot, the fall time is ~16ns, does this acceptable for TCA9543A? Any potential quesion?

    Thanks and Best Regards,

    Will

  • 0 in reply to Will Wang47
    TI__Prodigy 380 points

    Hi Will,

    No problem! In regards to your question, the fall time the customer is seeing is acceptable since the TCA9543A doesn't take into consideration the fall time. As long as the customer is not seeing any undershoots there shouldn't be any problems. Please let me know if this answers your question. 

    Regards, 

    Rosemary