[sdiy] CMOS chip questions

[David G. Dixon]

> > Dave Manley: If we are on the same pancake with that Sun rotating
> > around, just use 74HC(T).
> >
> >
> Hi Samppa,
> 
> I think I'll drop acid and then try and re-read your suggestion!  On the
> pancake that I'm on, 74HC(T) has a max input voltage of around 5.5v with
> VCC max=7V.  Connecting CD40xx with +15V Voh is probably not the best
> idea.
> 
> Now on the other hand, if you're proposing that there's no need to use
> CD40xx at all, and just design in 74HC then that's a different waffle
> completely.

I think we covered this ground a couple of days ago, re: putting 78L05 on a
15V board to power any 5V chips as needed.  Of course, if you've already got
TTL on the board, then presumably you're already constrained to 5V on the
digital end of things, which is where this whole discussion started
anyway...