• State Answer Suggested
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 33 subscribers
  • Views 116 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

TCA9535: undershoot tolerance

Fanbin Meng
Expert 4880 points
Part Number: TCA9535

Hi Team,

Huaqin server team is evaluating our TCA9535, when they configue the IO as the input, They found that the undershoot could reach -2.5V and the undershoot would last for 65ns.

Unfortunately they haven't reserve serial resistor to slow the slew rate down.

Could you help confirm if it is safe for our IC and is there any risk for the reliability.

I would keep this E2E forum posted to our customer.

  • 0
    Guru 243180 points

    This is OK only if the clamp current is below 20 mA.

    According to the IBIS model, that current will be reached at about −3 V in the typcial case, but at −1.49 V in the worst case.

  • 0
    TI__Mastermind 49040 points

    Hi Fabian,

    I can check with our design team to see what their thoughts would be (emailed but the main contact is out of office until the 27th) but from a datasheet point of view, this is definitely outside the absolute max ratings we spec so from a TI perspective we can't recommend to the customer to keep it as is.

    It would be better to limit the current like Clemen's pointed out or place clamping/schotty diodes on the line to clamp the voltage to be within the allowable spec.

    -Bobby