Replacement for a DEC 7474 Chip

ben bfranchuk at jetnet.ab.ca
Tue May 17 01:35:05 CDT 2022


On 2022-05-16 1:50 p.m., Eric Smith via cctalk wrote:
> On 2022-May-15, at 3:53 PM, Eric Smith wrote:
>> I specifically said 74x74. Early TTL flipflops were very crude by
> comparison.
> 
> On Mon, May 16, 2022 at 11:28 AM Brent Hilpert via cctalk <
> cctalk at classiccmp.org> wrote:
> 
>> pre-TTL != early TTL
>>
> 
> No, but 7470, 7472, 7473, and 74948  were _very_ early and were also very
> crude, as were their later L and H variants. 7474 was slightly later, and
> less crude.
> 
> It should also be noted that the 7400 series was NOT the first commerical
> TTL integrated circuits. The earlier TTL flip-flops were even more crude,
> but I imagine the engineers that used them were nevertheless delighted at
> the advance over RTL and DTL.

Did DEC not use a few Non TTL chips to reduce I/O loading on the bufferd 
lines?
Ben.



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