On Mon, 25 Mar 2013 14:56:25 -0700, Hal Murray <[email protected]> wrote:
> >[email protected] said: >> S/LS logic was introduced in the mid 70's, F/AS/ALS around 1980, HC was >> early 80's. By the third 7400 generation (F/AS/ALS) the problem was well >> known with parameters available and the logic fairly hard to it. > >The problem is well understood in the right circles, but we wouldn't be >having this much of a discussion if it really was widely understood. > >The parameters are not readily available. I've never seen them in data >sheets. Sometimes you can find them in app-notes, but those are usually just >typicals. I don't remember seeing any worst-case test results. Peter Alfke >from Xilinx did a lot of good work in this area. Besides the rare application note, I have seen metastability data in ECL datasheets and in datasheets from other logic families when the part was specifically described as hardened against metastability. It would be fun to build a test fixture to characterize metastability in some popular logic families from various manufacturers. I lack the right kind of oscilloscope to do it the easy way but maybe there is a more sophisticated way. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
