Hi Glenn,
As to U241, the internal gates are just used as inverters by tying the inputs together, so NAND or NOR makes no difference here. Each is a drop-in replacement for the other in this case; no PCB layout changes required. I can't think of a good electrical reason to prefer one part to the other in mid-production -- they differ negligibly in prop delay, for example. Perhaps it was just what they could get at the time, or get at a good price, perhaps.
-- Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
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On 5/1/2024 9:54 AM, Glenn Little wrote:
Another question is U241.
It is listed as 74S00 or 74S02 depending on serial number range.
Why would this part be changed?
