Fw: Deck of IBM PLAYING CARDS GOES FOR $325

Chuck Guzis cclist at sydex.com
Sun Dec 18 02:22:58 CST 2005


On 12/17/2005 at 10:37 PM woodelf wrote:

sites.
>I  downloaded some motorola application notes from bitsavers.
>Wow they sure had a  lot of  different types of  TTL. I wonder how only 
>the 74xx became the only TTL used today?

I think the short answer is "second sources"--you had at least 4 big
players, TI, National, Moto and Fairchild all producing 7400-series logic.
Some of the earlier TTL (Moto 400/500-series) had mid-line (pins 4 and10)
power supplies, which turned out to be not as convienient for PCB layout.
And, although it's largely forgotten, 7400 TTL shares a fair number of
pinouts with the older DTL circuits.

By the time LSTTL was out, everyone had pretty much standardized on the
74xx line.

My guess, anyway.

Cheers,
Chuck





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