9 Dec
2007
9 Dec
'07
5:36 a.m.
On Saturday 08 December 2007 18:00, Brent Hilpert wrote:
"Roy J. Tellason" wrote:
Hm, I had no idea that stuff was around that early on. My first encounter
with those parts was around 1970, and I still have that particular databook,
which had the standard parts and the H and L variants.
On Saturday 08 December 2007 02:03, Brent Hilpert
wrote:
I wish I could, but without the ref ...
For what I do recall, the suggestion in the article was that this was the
first use or choice of 5V for the logic supply, although I can't remember
whether the 5V was a choice of whim from which other design parameters
followed, or whether the 5V was an engineered outcome.
Even though I found it an interesting anecdote however, there were, or
would still be (IMHO) a couple of historical links necessary to show that
there was a causal connection/influence to the 5V supply standard of the
later DTL & TTL integrated circuit families.
The earliest reference for real ICs I have is a TI product catalog from
1965. The first products mentioned are the "NEW! Series 54 TTL"
(SN5400,5410,5420..5470) (4.5 to 5.5V of course). The commercial 74xx
versions apparently followed a little later. Another anecdote I ran across a few years ago in
the IEEE AotHoC (which
I wish had kept a ref to), was of an IBM engineer working on one of the
first transistorised designs in the mid-50s (ECL IIRC), telling the
story of how he chose 5 Volts for the logic supply.
I've wondered often how the various supply voltages I run into get
chosen...
Care to elaborate on that a bit? Five other digital IC families are mentioned:
- Series 53 Modified DTL (SN53x) (different from 'standard' DTL) (3 to
4V) - Series 51 RCTL (SN51x) (3 to 6V)
- Series 51R (severe environment versions of 51)
- Minuteman Series DTL (SN337A..) (produced for the Minuteman II missile)
(+6V & -3V)
- Low-power RTL (SN7xx..) (would become one of the 'standard' RTL
families) (3V)
A Fairchild catalog from 1966 presents standard 900-series DTL and some
9000 series TTL with 5V supplies.
I've never heard of most of those, though I think I do have some mention of
those 9xx/9xxxx numbers in my parts pages. I also have some more tech info
on hand here that I've downloaded but haven't plowed through yet or installed
into the charts...
.. and I may be repeating myself on the list, or this
may be more
well-known than I realise, but another somewhat novel point that is
apparent from the TI catalog is that the "SN" prefix on Texas Instruments
ICs is short for "Semiconductor Network", an alternative phrase before
"Integrated Circuit" became the more accepted phrase.
Well *I* never heard about that one before, and I've wondered for some time
what the heck it stood for. :-)
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-
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