why the ripple power shownon input of 74ACT04

David Zhang16358

Expert 1860 points

I have connected the 74ACT04 as attached picture.

why the ripple power shown on the 5V input of 74ACT04 ?

When disconnect 74ACT04 from others, the 5V is stable.

Thanks.

over 14 years ago

0 Chris Cockrill over 14 years ago

TI__Mastermind 46480 points

is your bypass cap right on the Vcc pin?

Are the input lines that are tied together equal lengths. If not you could be having bus contention for a short amout of time.

Using a lower power part with slower edges would probably fix the problem. Something like the HCT04 SN74HCT04. However I supect you tied these togather to get more output drive

0 David Zhang16358 over 14 years ago in reply to Chris Cockrill

Expert 1860 points

Yes, I tied these tied these togather to get more output drive.

My bypass cap is right on VCC pin.

0 David Zhang16358 over 14 years ago in reply to David Zhang16358

Expert 1860 points

I think the ripple voltage shown on Vcc is from the output signal which affect the near +5V VIA.

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why the ripple power shownon input of 74ACT04