19 Jun
2009
19 Jun
'09
1:42 a.m.
----------------------------------------
Date: Thu, 18 Jun 2009 18:27:18 -0700
From: hilpert at cs.ubc.ca
To: General at invalid.domain
Subject: 723 IC origins / was Re: Hardware Hobbyists vs. Emulator Jockeys
blstuart at bellsouth.net wrote:
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.
Hi
I used one in the control for one of the voltages
in a mass spectrometer in 1976. It was an old part
even then as I bought it at a surplus shop.
Dwight
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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.