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

[blstuart at bellsouth.net]

> 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.

Could be.  It's one of the thinnest of the National books
I have, and it was distributed through Radio Shack.  So
it might well be a "greatest hits" compilation.  It does
include the [123]09, [123]17, 120, [123]23, [123]25,
[123]26, [123]27, [123]40, 341, 342, [123]45, 78XX,
78LXX, 79XX.

BLS