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CC2674R10: I/O Input Specification

Stuart Baker
Genius 10630 points
Part Number: CC2674R10
Other Parts Discussed in Thread: SN74AVC2T244

Tool/software:

I'm working with a customer who is using the SN74AVC2T244 as a level translator between another MCU and the CC2674 device. We are finding that the drive strength of the level translator is quite high, and this is causing ringing at the input of the CC2674. The overshoot is around 4.11V and the undershoot is around -1.41V. The VDDS I/O rail used for the CC2674 is nominally 3.3V.

This technically violates our datasheet specs, but only persists for ~7ns. We are wondering if this should be a concern that would prematurely wear out the CC2674 device. The obvious solution would be to add some small series resistance near the level translator, but the customer is trying to avoid an unnecessary board spin if possible due to a very tight production timeline. Please see the attached scope images:

Thanks,

Stuart

  • +1
    TI__Expert 6520 points

    Hi Stuart,

    No, the customer should not operate the device beyond the absolute maximum rating. The absolute maximum represents the value at which the part can tolerate, but not operate at. As noted in the data sheet (footnote 1 of the absolute maximum rating table):

    Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

    Thanks,

    Jake

  • 0 in reply to Jake Pulliam
    TI__Genius 10630 points

    To conclude this thread, a discussion was had offline. The main conclusion is that TI has no reliability and test data beyond the absolute maximums in the datasheet. The device may operate successfully under the customer's specific conditions initially, and at 3.3V nominal and ~25C, as the customer has already shown in a small population of devices. However, it is not known at what point the stresses would result in catastrophic failure, especially across a large number of devices and larger temperature range.

    The official position of TI remains to add series termination at the driver side (level translator) such that the Absolute Maximum Ratings are never exceeded.

    Thanks,

    Stuart