17 May
2001
17 May
'01
3:43 a.m.
On Tue, 15 May 2001 22:38:46 GMT Pete Turnbull
<pete(a)dunnington.u-net.com> wrote:
According to Webopaedia and at least one history
website, Texas released
the first SSI TTL chips in 1965 and LSTTL in 1970.
I've checked my "System 74 Designer's Manual", and it's
dated 1973. It includes some reliability figures based on
chips manufactured in 1969, though.
But an oddity did show up: the chip pinouts sometimes
differ between ordinary 74 TTL and the 74H version. A 7401
has a completely different pinout from a 74H01, for
instance. And a 7454 has one less input than a 74H54 (it's
an AND-OR-INVERT chip). I hadn't spotted that before.
--
John Honniball
Email: John.Honniball(a)uwe.ac.uk
University of the West of England