723 IC origins / was Re: Hardware Hobbyists vs. Emulator Jockeys

[Brent Hilpert]

Brent Hilpert wrote:
> 
> blstuart at bellsouth.net wrote:
> > >>
> > >> I just checked what I have.  My 1977 Voltage Regulator
> > >> Handbook doesn't list it at all.
> > >>
> > >> My 1980 Linear Databook
> > >> includes a couple of switchers among the typical applications.
> > >> That would suggest such a data sheet would have to be
> > >> around 1978 or 79.
> > >
> > > The earliest example I have at hand for the 723 is the manufacturer's schematic
> > > for the Wang 520 calculator. The power supply page with two 723's on it (used
> > > just in linear mode), is dated early 1971. Perhaps the earlier handbook was
> > > from a manufacturer that didn't 2nd-source it.
> >
> > It was a National book, but I can believe that it could
> > well be incomplete.  That's why I equivocated and said
> > it suggested a time frame.  The existence of it in these
> > earlier systems clearly moves the lower bound.
> 
> Funny that it wouldn't even be mentioned, perhaps the chip was old enough by
> that time that it got left out of a current-techniques handbook (as opposed to
> a databook) in favor of newer stuff.

Come to think of it, the 723 probably originated with Fairchild, as Fairchild's
linear stuff were 700-series numbers (702,709,710,741,...).
National may well have been a 2nd-source for it.