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TPD12S016: Question about LS_OE, CT_HPD and SCL_A/SDA_A pulled up supply

Expert 8760 points
Part Number: TPD12S016

Hi team,

My customer has following questions.
Please let me know the answers.

①Is there a signal input sequence between CT_HPD and LS_OE?
  If there is a signal input sequence, please let me know the order and time value.

②Do CT_HPD and LS_OE have rise/fall time specifications?
  If they have, please let me know the values.

③I want to know a wait time from the time LS_OE and CT_HPD become high to the time I2C
  communication is permitted.

④SCL_A and SDA_A pulled up to VccA in the datasheet Functional Block Diagram.
  But I think SCL_A and SDA_A are pulled up to 3.3V(internal). Because SCL_A and SDA_A have
  a certain delay from the time the power supply of the VCCA is turned on until they are pulled up.
  Is this correct?

Best regards,
Fumio Nakano

  • Fumio,

    Here are my answers to your question:

    1. There is no relation between CT_HPD and LS_OE, so no sequencing is requried.

    2. CT_HPD controls the gate of a load switch as part of the level shifter, so there is nor rise fall time requirement and LS_OE also is an enable for the level shifters. There is not timing or transition requirement as long as the signals have settled before data is transmitted across any of the data inferfaces.

    3. The longest nominal delay for a signal controlled by LS_OE will be 28uS. It would seem reasonable to me to wait 100uS to give the load switch and level-shifters time to settle before data is passed.

    4. The pull up is connected to the VCCA rail for those pins, so there is no relationship to the internal 3.3V power rail.

    Please let me know if I can answer any further questions.

    Regards,
    Chuck
  • Hello Chuck-san,

    I appreciate for your prompt reply.
    Your answer was very helpful.
    Thank you so much!!

    Best regards,
    Fumio Nakano
  • Fumi San,

    I am happy I could help.  If you need more help, please reply back. If your question is answered, please click  Verify Answer 

     

    Regards,

    Chuck