Re: [sdiy] VCO and expo converter question

[Roman]

Well, it's simple CMOS inverter, 2 transistors designed to work fully closed or open, where nobody cares for their cutoff voltage, leakage and temperature dependence. I simply wouldn't call it a stable analog component. I'd expect big temperature drifts, and poor EMI immunity.
However, I have no experience using 4069 in analog way, I only have strong feeling this is way out of "precision" league.

So you say 4069 VCO core works as good as opamp one?

Roman

---- Wiadomość Oryginalna ----
Od: René Schmitz <uzs159 at uni-bonn.de>
Do: Roman <modular at go2.pl>
Kopia do: ryan <destrukto at gmx.net>, synth-diy at dropmix.xs4all.nl
Data: Mon, 24 Nov 2003 11:21:28 +0100
Temat: Re: [sdiy] VCO and expo converter question

>> transistor pair (in human language precision=expensive), then why
>> bother using 4069 as integrator and schmit trigger. CMOS can't give
>> you the stability that your new expo converter provides. I'd change
>> it into standard opamp integrator and comparator. But anyway it's
>> only my sick opinion. 
>
>What makes you think that it wouldn't be stable?
>
>Cheers,
>  René
>