Alt-BEAM Archive
Message #02151
To: Steven Bolt sbolt@xs4all.nl, beam beam@corp.sgi.com
From: Sean Rigter rigter@cafe.net
Date: Fri, 09 Apr 1999 07:24:35 -0700
Subject: [alt-beam] Re: Better design was Better 74HC design
Hi Steven,
I agree 100% : I interpreted your earlier post as a "general"
recommendation of HC over AC. Perhaps "when HC and not AC" is
appropriate?
best regards
wilf
Steven Bolt wrote:
>
> On Thu, 8 Apr 1999, Wilf Rigter wrote:
>
> > Issues like "Why AC and not ALS" or "Why 74C and not 74HC" would be fun but
> > rather than "championing" a logic family, I prefer to concentrate on solving
> > problems with novel design solutions including your own excellent analog
> > sampling method and so many other of your contributions.
>
> Hmmm... I see that I should have worded it differently, or maybe
> should have used even less words.
>
> People are still using 74LS, 74HCT and any other 74XXX where 74HC
> is specified. "Can I use ..." and "Why not use..." are the
> questions I answer most often. TI points out a difference between
> families which are often thought to be equivalent even by
> `advanced' BEAMers, and does it in an easy to understand way. It
> seemed worth the minor effort of posting.
>
> Of course there are valid reasons for using 74AC, or a sensible mix
> of two or more families. So when someone thinks he/she needs the
> higher sink/source capability of 74AC, he/she may consider "Yes,
> but in this part of my circuit, that means (solar) power going to
> waste - no, wait a minute, Wilf said Icc is *much* lower at 2V.
> Maybe I should look around for relevant data or do a test, like he
> did."
>
> Anyway, I didn't intend to simplify. In fact, I usually try to
> show the importance of making one's analysis as complete as
> possible. If the posting you refer to gave a different impression,
> that's regrettable.
>
> Best,
>
> Steve
>
> ----------------------------------------------------------------------
> # sbolt@xs4all.nl # Steven Bolt # popular science monthly KIJK #
> ----------------------------------------------------------------------
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