[sdiy] CEM3374 vco temp sensor

[James Patchell]

I never used the 3374, but I think the idea was to take the temp sensor 
output and use that for the reference for the D/A converter that will be 
controlling the pitch.  The D/A will essentially provide the multiplication 
function.  You could also use the voltage to control the gain of an OTA 
much like I have done on one of my VCO's

http://www.oldcrows.net/~patchell/synthmodules/100-1007.pdf

I use an LM13700 or LM13600 to make a very linear two quadrant multiplier.

At 03:54 AM 10/17/2003 +0200, Karl Dalen wrote:
>The CEM3374 dual VCO have a temp sensor, i asume
>it uses bandgap design but how does that achieve the
>+3500ppm scaling, does it perhaps use a 3340 multiplier?
>
>Its no doubt that it works splendid but how sure
>could one be that the temp drift are equal on both
>VCO's?
>
>It also say that a +/-90mv covers a 10 octave range
>wouldent that put quite some precision requirements
>on the OP amps in the DAC reference feedback path
>in terms of V offset drift with TC?!
>
>Are there any +3300/3500 silicon temp sensor availabe
>on the market? Perhaps it would be more linear then a
>NTC, No? Just speculating a bit!
>
>KD
>
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         -Jim
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