[sdiy] 4069 VCO to get started? My reply

[harrybissell]

Nicolai Czempin wrote:  <snipp'd and diced...>

>
> Let me explain briefly why I won't be using the 4069-based design for
> now....
>
>  the mere fact that it is a CMOS-gates-based design makes it a step up from
> the
> basic analog stuff...
>
> Now, it may seem that I'm contradicting myself, by using op-amp-based
> designs. Perfectly correct, and I *will* want to build a VCO using
> discrete components. I guess I'm drawing an arbitrary line at the
> analogue vs. digital border for now....
>
> That's why I called the circuit "impure" BTW (tongue-in-cheek, of
> course), in case you hadn't realized.
>

Actually, you should consider the "4069 hex inverter" to be as an
analog array of six PMOS/NMOS pairs of transistors fabricated on
a single (monolythic) substrate. Check out the data sheet, that is
EXACTLY what you are getting.

Yes.. some unenlightened folks would call that a "digital" function...
but we analog designers know better   :^P

The 4007, 4049, and the 4069UB are all basically transistor arrays.
A very large portion of the "classic" synthesizer designs uses these
parts as analog components. RCA even included some of these in their
ANALOG data books (of yore...)

What could be more 'pure' ???

H^) harry