[sdiy] VCO reset time

[Scott Gravenhorst]

"JH." <jhaible at debitel.net> wrote:
>> Right, one thing to keep in mind is the maximum slew rate your opamps 
>> can handle. 
>
>Good point!
>
>Why use an opamp here at all?
>

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?

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