Pre-7400-series logic ICs (was Re: Weird 7410)

From: Ethan Dicks <>
Date: Wed Mar 6 15:08:54 2002

--- William Donzelli <> wrote:
> > I was just reading a bit on TTL while looking for something else.
> > In 1965 a 7400 gate was $20 and Candy bars 5 cents.
> Probably not 7400 series (earliest 7400 series I have are from late
> 1968).

I _think_ I have some 7400-series chips from 1967, but no earlier. They'd
be in a PDP-8/L if, in fact, I am remembering correctly.

> There were a number of logic families that were out in the mid-1960s.

Indeed... I am looking for some (and not expecting to find any) to
build a replica of a DW08, DEC's pre-TTL TTY interface made from W-series
and R-series logic. The W706 and W707 boards use a Motorola logic family
with 3 digits, not 4. The schematic for the W707 transmitter shows...

  1 x MC799P "Dual Power Buffer" ('P' for Plastic package, 0C - 70C rated)
  8 x MC724P "Dual J-K Flip- Flop"
  5 x MC724P "Quad Input Gate" (NAND)
  5 x MC789P "Hex Inverter"

GND is on pin 4, Vcc is shown to be +3.6 VDC on pin 11. The schematic also
suggests that they are 14-pin ICs, but no way of telling if they are DIP or
some other packaging (but the mention of a plastic package is a hint).

I have to say that I have been previously unaware of any logic family that
used +3.6V for Vcc. Anyone have any info from 35 years ago?

> Yes, in 1965 I can believe $20 per chip!
> And then, ten years later, 19 cents per chip...

Thank you, Gordon Moore.


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Received on Wed Mar 06 2002 - 15:08:54 GMT

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