• State
  • Locked Locked
  • Replies 3 replies
  • Subscribers 33 subscribers
  • Views 431 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65987D: I2C fall time

CK Ho
Expert 1780 points
Part Number: TPS65987D

Dear sir,

Our customer is using TPS65987D and wants to ask a question.

In TPS65987D datasheet, the I2C output fall time minimum is 12ns (fast mode).

But what they measured is about 2-3ns. It is out of spec for them.

They want to know if there is any impact or side effect if the I2C fall time too fast?

  • 0
    TI__Expert 4455 points
    Hi CK,

    Customer may want to check the capacitance on the line or trace layout.

    While I2C is a low speed interface, I need to warn that it is still out of spec and there is a chance that fall time in this range (2ns) can lead to transmission line or signal integrity issues in the system.

    Regards,
    Scott
  • 0 in reply to Scott T
    Expert 1780 points

    Dear Scott,

    Sorry, I want to confirm that what does the "I2C output fall time" mean in our datasheet??

    Is it the output spec for master or input spec for slave??

  • 0 in reply to CK Ho
    TI__Expert 4455 points
    Hi,

    I do agree that this is specified as an output value for a given range of bus capacitance and pull up voltage. I would double check bus capacitance, pull up resistor and any series resistance.

    Regards,
    Scott