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DM8148 I2C rise/fall time, does this assume 10%/90% V swing?

Brad Caldwell
Genius 12595 points

In DM8148 datasheet revised Sep 2012

 Table 8-44 Timing requirements for I2C Input Timings

 #9, #10, #11 & #12 : Rise and fall times

 Is this assuming a10-90% voltage swing for transition time?

 

  • 0
    TI__Guru*** 125430 points

    It's relative to Vih,min and Vil,max.  Those are the numbers dictated by the I2C specification itself, and that's also how they're referenced in the standard.

    This is also noted in Section 8.1.1 of the data manual, i.e. we state that all rise/fall parameters are related to Vih,min and Vil,max.  There are a few cases that are different such as MMC which is why for that specification we explicitly state that we're referring to the 10%-90% transition time.

  • 0 in reply to Brad Griffis
    TI__Genius 12595 points

    Thanks Brad, that makes sense.  To complete this forum post for others who may come across it, here are the values for the DM8148 so in this case it's really 30% to 70% for rise time