Replacement for a DEC 7474 Chip

Chuck Guzis cclist at sydex.com
Sun May 15 10:11:42 CDT 2022


On 5/15/22 01:16, Eric Smith via cctalk wrote:

> I don't think that worked on any TTL (or CMOS) 74x74 flip flops, except
> maybe by accident if you shorted the output enough to draw Vcc down (or
> ground up) enough to disrupt the FF, and then you have other problems.

Checking my old Moto databook, the old FFs appear to be capable of
having the outputs jammed.   At first glance, both the 7472 and 7473 FFs
had unbuffered outputs.   Most early latches, likewise.

Of course, the very early TTL was density-constrained, so FFs like the
MC512/MC563 are of course without buffered outputs.

--Chuck



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