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SN74LVC07A: Failure rate of this IC is too high

Parag Thakkar
Prodigy 20 points
Part Number: SN74LVC07A

Hi

We are using SN74LVC07A in many of our applications as buffers as well as voltage shifter from 3.3 to 5V. However we are facing a lot of failures in these ICs and as such are not able to understand the reasons. For e.g. we are using this IC as buffer for matrix keypad with voltage of 3.3V. In many cases one of the lines go bad i.e. output remains at same level even though input is changing.  Can you please help as in why these IC can fail?lv_issue.pdf

  • 0
    Guru 243080 points

    The most common cause of damage is that the absolute maximum ratings were exceeded. I'd guess that you got ESD from the keys.

  • 0 in reply to Clemens Ladisch
    TI__Genius 16725 points

    Hi,

    There can many reason a part will fail if used outside the recommended datasheet specs. You will have to provide me with more information on our use case for me to understand what spec is being violated causing this failure. As clemens has mentioned, ESD can be a reason for your part to fail. Our parts are only spec'd for ESD protection during manufacturing. So I would recommend adding external ESD protection to your devices.

    Thanks!

    -Karan

  • 0 in reply to Karan Kotadia
    Prodigy 20 points

    Hi

    What kind of information in required please let me know. My use case as that I am using this as a voltage shifter from 3.3V to 5V or vice versa and as a buffer. As for ESD, I don,t think that is the reason for the failure as no metal part is exposed for ESD. 

  • 0 in reply to Parag Thakkar
    TI__Genius 16725 points

    Hi Parag,

    What size pullups are you using? What kind of load are lines driving? What frequency are you operating the device at?

    When you say device fails by the output not changing even with input changing, is the output constantly a low or in high impedance?

    You said your input signal is from a matrix keypad, has it been properly debounced? What are the rise and fall times of the signals on the input?

    I see 3 devices on the small schematic you sent. Is a specific single device out of the 3 failing? Or is it randomly one of them?

    I would recommend you start an FA with TI. You will have to send in some damaged samples to test. They will check if the ESD cells have been damaged and we would know our answer for ESD.

    Thanks!

    -Karan