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SN74LV244A: Please tell me about the case where the undershoot is below -0.5V.

user4691663
Prodigy 40 points
Part Number: SN74LV244A

Hello.

Please tell me about the case where the undershoot is below -0.5V.
Not found on the datasheet.

If the input waveform is -0.5V or less, are there any relaxation conditions according to the time regulation?

For example
If the input voltage below -0.5V is 20ns or less, up to -1.0V is acceptable.
Such

Regurd,

 Hirofumi Yamaguchi

  • 0
    TI__Guru* 96591 points

    Hello Yamaguchi-san,

    The datasheet is clear on this:

    You may exceed -0.5V so long as the current does not exceed the rated maximum. There is no time limitation.

  • 0 in reply to Emrys Maier
    Prodigy 40 points

    Hello Emrys Maier,

    thank you for your answer. I have an additional question below.
    We are currently measuring the waveform with an oscilloscope.

    (1) Undershoot of input pin
    　If the input current is 20mA or less, the undershoot will be -1.0V. Will this lead to component failure?

    (2) Allowable voltage value for undershoot of input pin
    　What V can undershoot be allowed when the input current is 20mA or less?

    Regards,

    　Yamaguchi

  • +1 in reply to user4691663
    TI__Mastermind 23373 points

    Yamaguchi-san,

    As Emrys's response indicated above, the datasheet is pretty clear, you can exceed the rating as long as the current is limited below the spec listed. -1V should be fine if you don't exceed the max spec. If you're concerned about it, a series resistor on the output can limit the overshoot/undershoot and the current.

    Thanks,
    Rami