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

over 2 years ago

0 Emrys Maier over 2 years ago

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 user4691663 over 2 years ago 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 Rami Mooti1 over 2 years ago in reply to user4691663

TI__Mastermind 23853 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

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