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TXS0104E: timing issue

Shu-Cheng LIN
Guru 11785 points
Part Number: TXS0104E
Other Parts Discussed in Thread: TLC59116, TAS5760M, PCA9306

Hi Sirs,

We have a timing issue about the rise time is too fast.(measuring: 8ns, spec: 20ns~300ns)

  1. Could you provide the latest spec of TI TLC59116IPWR for I2C timing?
  2. Could the one-short circuits be turn off for the TXS0104?
  3. Is there any side effect when the rise time is too fast to cause over spec?

 

l   The block diagram is shown as below:

Thanks!!

  • 0
    Guru 317320 points
    The TLC59116's timing requirements are just copied from the I²C specification.
    In practice, faster edges will work fine as long as there is not any ringing that would make the voltage dip below 70% again.

    The TXS's edge accelerators cannot be disabled.

    If you want to slow down the edges, increase the 47 Ω and/or 100 pF values.
  • 0 in reply to Clemens Ladisch
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    Actually we have use 47ohm and 100pF RC delay circuit already, because one-short pull-up driving too strongm, there will effect rise time always smaller than 20ns. (Tr: 8ns)

    l If we use Cap 220pF, The wareform will be Charging triangle wave( Tr: ~17ns, still smaller than 20ns)

    l If use too large Cap value, there couldn't to right high level value.

    We saw there have another IC "TAS5760M", the Tr and Tf as long as<300ns is OK.

    We would like to know does TI have definition same I2C spec between TAS5760M and TLC59116IPWR?

    Because if yes, the TLC59116IPWR spec is <300ns, we think this test result is reasonable

  • 0 in reply to Shu-Cheng LIN
    Guru 11785 points
    Hi Sirs,
    Sorry for pushed,
    If have any confuse on this please kindly let us know. Thanks!!
  • 0 in reply to Shu-Cheng LIN
    TI__Guru* 97046 points
    I'm not really sure what you're trying to do. You shouldn't add capacitors to the TXS -- it works very well with I2C the way it is. TI also offers I2C specific devices (such as PCA9306) if you are wanting to get something specifically made for I2C.
  • 0 in reply to Emrys Maier
    Guru 11785 points

    Hi Sirs,

    Thanks for your reply.

    Please let me summary our question.

    1, Looks, TI TLC59116IPWR rise time must meet 20ns< Measurement value <300ns. right?
    2. TLC59116IPWR rise time can same as TAS5760M (<300ns)？
    3. Continue Q2, If different rise time between TLC59116IPWR and TAS5760M, why? because I2C IF electric circuit design have different?

    Thanks!!

  • 0 in reply to Shu-Cheng LIN
    TI__Guru* 97046 points

    Hi Shu-Cheng,
    I think your question is directly related to the TLC59116 and not the translator -- I have opened a thread on the other forum to ask, located here: https://e2e.ti.com/support/power_management/led_driver/f/192/t/649763