Is there such a thing as a variant of the 4000 series CMOS logic chips which has TTL compatible inputs?
Something like the 74HCT but for 4000 series.
The reason I ask is that I am looking to switch a number of 12V low current signals from a 3.3V or 5V source (the grids and anodes of a VFD, while the filament is running from a 5V square wave), and 4000 series running at 12V would be ideal for that (e.g., the 4069). However, in all the variants of the 4000 series I have found, the \$V_{IH}\$ scales with the supply voltage (as is normal with CMOS logic), which at 12V puts it way outside the range of a 5V logic signal, let alone a 3.3V one.
Alternatively, can you suggest a different family of chips? It wants ideally to be usable by novices, since it's going to form part of a tutorial.