Delete comment from: Ken Shirriff's blog
Back in the 1980s, most of the chips in ceramic packages were Mil-Spec. Manufacturers had to commit to producing the product for an extended period of time. The largest market even then was commercial chips in plastic packages, so some of the rationale for not using certain chips was due to availability from the manufacturer in the right package, tested in the right way. Also, these chips had a wider temperature range than commercial devices, that sometimes caused problems.
Now, most chips are totally digital, but then even digital chips often had analog circuitry inside. Also, CMOS didn't go mainstream until the later 1980s, many of the microprocessors in the 1980s were NMOS, which used effectively a resistor for pull-up instead of a transistor.
Jan 17, 2020, 6:05:11 PM