[sdiy] VCO reset time

[JH.]

> Yes, the René Schmitz 4069UB VCO is an example of a core that uses no
> opamps at all.  Do you think the ALD1103 series you've previously
> mentioned might be better?  That's quite a good VCO for such lowly and
> inexpensive beginnings as a 4069UB.  Did you have other structures in
> mind besides the dual complementary MOSFET inverter?  I was thinking that
> generally the MOSFET technique would be good due to low leakage.
>
> I suspect that the ALD part might be quite superior because it's on
> resistance (for cap discharge) is typ. 180 ohms compared to approx 5000
> ohms for the 4069UB (calculated from data sheet approx 3 ma source drain
> current at 15 volts at around room temperature).  Or is this way off?


A simple FET source follower will do. No need to build an active integrator.
Drawback: expo converter will not work into a virtual GND node anymore.
(Does this matter?)

JH.