4000 series logic with TTL inputs?

Question

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.

Answer 1

In the end I opted for ULN2003 chips with 10K pullup resistors. Only tiny currents (nA or even less) are needed for the anodes and grids, so 10K is perfectly fine. As it turned out I really needed around 30V rather than the 12V I was planning to get good brightness from the VDF when multiplexing 1:9, so the ULN2003 was perfect for the job.

Kudos to @oldfart for reminding me of the existence of them.

Answer 2

You can use the hex inverter with Schmitt-trigger inputs 40106 in combination with a level shifting network at the inputs.
The level shifting network should shift the input signal up so both levels go above/below switching levels of the Schmitt trigger. It could be done with a voltage divider (connected to Vdd and the input signal) or with a resistor-diode combination.

At least for the 5V signal it should be doable (typical hysteresis is 2.3V @Vdd=10V and 3.5V @Vdd=15V).

Answer 3

" 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 VIH 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."

I don't know what you referring to (VFD? varible frequency drive and vacuum tube elements?). But typically to control something like this is a standard transistor circuit. So the ULN200x,ULQ200x series is what you looking for as device (a multichannel current switch). Ive used them in many things, from switching lamps, to driving little stepper motors.