• State TI Thinks Resolved
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 42 views
  • Users 0 members are here
Support feedback
Options
Options
Related

Original question:

TCA6408A: Interface timing requirements

TCAL6408: I2C Interface Timing

Eric Yang
Prodigy 30 points
Part Number: TCAL6408


As we know the I2C rise/falling timing requirement as below. We tried to chnage our serial resistors over 100Ohm from 0Ohm but the rise/falling time didn't have change. Would like to confirm the rising/falling time to quick (15.7ns) have any impact and concern? Should we waive this fail item?

 

  • 0
    TI__Guru 54678 points

    Hi Eric,

    This is a spec in the I2C standard that is not well defined. 

    I have not seen issues with fall times faster than the minimum. One worry is overshoots past GND when the drive strength is too strong, that's why I believe a minimum fall time was added. 

    From a data perspective, I have not seen customers affected from faster fall times, i.e. no digital bit errors from fast fall times. Bit errors tend to occur because of violations of setup and hold timings. 

    If you have the ability to control drive strength on your open-drain driver from the controller, it wouldn't hurt to reduce the strength. Otherwise, I have not seen customers have issues with our device from going outside this spec. 

    Regards,

    Tyler