max rise time SN74HC74

Ulrich Bertl

Intellectual 1460 points

Other Parts Discussed in Thread: SN74HC74, SN74LVC1G17, SN74LVC1G14

Is it possible to use the SN74HC74 with 3ms risetime and 3ms falltime at the Clock pin

over 8 years ago

0 Clemens Ladisch over 8 years ago

Guru 316760 points

That would exceed the allowed input transition time by only 600000 %. And on the clock input, any oscillations (see Implications of Slow or Floating CMOS Inputs (SCBA004)) would be especially bad.

You have to add a buffer with a Schmitt-trigger input.

0 ShreyasRao over 8 years ago in reply to Clemens Ladisch

TI__Guru 62080 points

Yes , completely agree with Clemens on the suggestion of Schmitt trigger input device to be used in case of slow inputs.
Please try SN74LVC1G14/SN74LVC1G17.

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max rise time SN74HC74