Usually the NAND. Tam
Usually the NAND. Tam
IIRC it's typically the NAND.
-- Cats, coffee, chocolate...vices to live by
What generally has less propagation time. ? A 2 input AND or a 2 input NAND gate for a given series?
I might have to dig up the datasheets for this... If anybody knows offhand, let me know..
D from BC
That used to be easy to answer. Gates were made of inverting elements (common emitter/drain transistor), and were unbuffered, so the inverting functions were faster (7400 vs. 7408, CD4011 vs. CD4081). However, it soon became common to buffer the inputs and/or outputs, sometimes even with 2 stages. There's no longer any general answer. A 74LVC08 is faster than a 74LVC00.
Anybody who tells you that he knows offhand, should not be trusted :)
LOL and almost a coffee spew..
Yep. Pre- and Post-Buffering are now commonly used to "standardize" propagation times.
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et |
Wow...I didn't know about the internal buffering spoiling the trend for NAND to have a shorter tp. I was rooting for NAND to be faster due to fewer transistors due to the already intrinsic inverting circuits to make the NAND topology.
Things change... I suppose it's always best to not skip out on checking the datasheets.
Thanks for responses everybody. D from BC
FWIW, that's pretty much what I was going to say. :-)
Cheers! Rich
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