LM566CN VCO

[Paul Schreiber]

For decent VCO (actually, a VFC: voltage to frequency converter) see the Analog
Devices AD654 www.analog.com

I use these over a 5Khz to 150Khz range to measure temperature (day job). Very easy to use.
Square/pulse out. Perfect for those EPROM clocking schemes. Very linear (0.05%). Cheap,
about $6ea.

Paul Schreiber
Synthesis Technology


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From: 	Scott Gravenhorst[SMTP:chordman at flash.net]
Sent: 	Tuesday, June 30, 1998 10:38 PM
To: 	synth-diy at mailhost.bpa.nl
Subject: 	Re: LM566CN VCO

On Tue, 30 Jun 1998 22:44:11 +0200, Rene Schmitz <uzs159 at uni-bonn.de>
wrote:

>At 23:05 29.06.1998 GMT, you wrote:
>>Well, the spec claims only 10 to 1 freq range.  That's only a little
>>more than 3 octaves.  Unless someone knows of a way to extend this,
>>that seems kind of lame for music.
>It seems that the 566 can be current controlled as well, and in this 
>case the sweep range is more like 1 to 100, I have a schematic for a 
>BBD phaser at hand where this is used. They hold the voltage input at
>some fixed level, and inject the current at pin 6. Hm, sounds as if one 
>could add a simple expo converter and have linear and exponential FM.

I went back to my National book and I see no mention of a change in
it's useful linear range for current control.  Where did you come by
the spec of 1 to 100?  If it is true, it would make an easy to build
VCO, but only if it is linear over that range.  Is it possible that it
will work over that range, but that it might not be linear enough for
music?  If I had one of these, I'd try it now, but I'd rather not buy
any unless I know I can make a VCO that's at least as linear over a
range equivalent to the FatMan's.

-- Scott Gravenhorst
-- FatMan Site: www.teklab.com/~chordman