SN74LVC2G08 Issue

kuya

Other Parts Discussed in Thread: SN74LVC2G08, CD74AC534

I have another question for you. I use Texas Instruments SN74LVC2G08. My application is reverse from "Ioff Supports Partial-Power-Down Mode Operation". VCC power is on, all inputs are in "high" steady state (output is low).
Now, VCC is still on, however, inputs to SN74LVC2G08 are power down. Is there any chance that I would get a glitch at SN74LVC2G08 output?

over 15 years ago

0 Chris Cockrill over 15 years ago

TI__Mastermind 46480 points

Hi Kuya

You should never float inputs on logic devices. You should use a pullup or pulldown resistors to prevent the inputs from floating.

0 kuya over 15 years ago in reply to Chris Cockrill

Prodigy 135 points

Chris,

Thanks for the previous answer, but the customer has one more question.

I would like to calculate the probability that the 8 outputs of CD74AC534 would power up as [ Q7:Q0 ] = 10101010.

Should I assume that each individual output will have 50% evenly chance to come up as 0 or 1? Much appreciated if you could advice me on this.

0 Chris Cockrill over 15 years ago in reply to kuya

TI__Mastermind 46480 points

All the outputs would most likely come up in the same state. There is no way to predict this but I would guess there is no way they woud come up 10101010.

You might be able to delay the clock by an RC time constand and get the part to clock in what is needed at powere up.

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SN74LVC2G08 Issue