[sdiy] uA726 transistor array

[René Schmitz]

Hi everyone!

>Jörgen Bergfors reported to me in a private email-session that he noted that
>the LM311 comparator where a source of thermally induced frequency shift. This
>is logical since the comparator is used to detect the phase-ramp against some
>stable level. The comparator core is another diffrential transistor-pair, so
>we should not be supprised.

Can someone quantify this effect? (The last few hundred ppm are the hardest ;-)

IMO having two comparators and thresholds (i.e. precision schmitt trigger) 
is better anyway, the drift will cancel.

>I've been thinking about MAT-04's too. What I really would like to see is a
>MAT-02 (which is a MAT-04 but with pair-wise wireing of transistors to better
>handle temperature gradients, a chip-trick being a bit hard to do otherwise)
>but with a handfull of extra transistors so that a distributed heater and
>multiple senses can be applied. 

Hmm, and just two hours ago I wondered if one could parallel the transistors in
a MAT04 to get lower rBE....

Cheers,
 René


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uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159