The original 805x part number began with 'i'. The programmable parts, initially, weren't i805x, they were i875x. By the late '80's they put the 'P' in front of their plastic parts. Presumably, they put the 'D' in front of their ceramic parts, but I can't prove that with any of my inventory. I avoided Intel-designed parts as much as I could.

You're certainly right about the P and the D, but they were AFTER the part number in the Intel 805x series. They were second-sourced by AMD and by Signetics, and the latter was acquired by Philips in the very late '80's. I don't believe Signetics produced reprogrammable parts, i.e. 875x's at all. In fact, I don't believe I've ever seen a ceramic windowed Signetics 8748 either, though they made the plastic-packaged parts en-masse.

If you don't read the specific manufacturer's datasheet, applicable to the specific component, when using 4000-series CMOS, you're likely to get what you deserve. There were numerous parts made by one manufacturer and not by any other, and there were also multiple component series, e.g. the 'B' series and the earlier unbuffered CMOS parts, and, later, the NSC 74C-series, some of which were simply equivalent to 4000B-series, and others not. Later on, there were 74HC- and 74HCT-series parts with 4000- and 4500-series names, e.g. 74HCT4053, and the like.

It all makes for interesting reading. Perhaps that's one reason why so many people quit using "family" logic and switched to programmable logic. With the evolution of cheap CPLD's, it became economically advantageous, too. Fewer parts, hence, fewer datasheets, smaller inventory, fewer holes in the PCB, if you like that technology, smaller board area, faster switching speeds ...

RE