CEM3374

[Rich Nelson]

Paul Perry wrote:
> 

> Jeff, if you look at the CEM data sheets you see that the output from
> pin 10  (which is +2.5v at +3300 ppm) is intended to be added onto the
> reference voltage from which the control voltage is derived.... this was done
> to simplify use of the chip in microprocessor controlled devices
> 

> 
> paul perry melbourne australia

Paul...

I believe that this voltage is actually available not be to added onto a
control voltage, but rather to
control the gain of an analog multipier in the CV path, or as the
referece voltage to a DAC in digitally controlled synths.

This adds a bit more circuitry. I personally find it simpler to use the
old method of putting a tempco in the feedback loop of the CV summer. 
But it is a shame to do this and "waste" that correction voltage which
is both a bit more accurate than using a tempco, and is derived directly
from the temperature of the IC die.

And you are correct that the linear CV can be fed into the reference
voltage point of the exponential converter.  Again... standard "old
fashioned" VCO practice.

rich
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