uA726 replacement

[Paul Schreiber]

>
>In fact, the much venerated CEM 3340 VCO chip used this heated substrate
trick
>with great success.  Warm-up time was < 30 sec, much better than (dare I
say it)
>tubes

This is an incorrect statement.

The 3340 does NOT heat the chip up. Rather, it *senses* the die temperature
and feeds a second-order correction current into the integrator.

The exponential converter is 70% of the temperature dependence. You also
have other
factors, such as the temperature coefficient of the integration capacitor.

The MOTM-300 Ultra VCO has *5* seperate temperature servo loops, does NOT
use a heater,
and can track within 0.05HZ over 6 octaves and within 0.2Hz over 10.

Paul Schreiber
Synthesis Technology
www.synthtech.com/motm