CEM3340 stability

Wim Verheyen catwim at innet.be
Mon Mar 24 19:51:47 CET 1997

Hi all,

>However, I am not so fond of the on-chip multiplier in the 3340. For
>some reason, many 3340's are still more temperature sensitive ...

I've used CEM3340's in my Aemit modular and they are rock-stable.
I have an engineering memorandum from Synton Holland that explains how to
increase the long-term stability of the CEM3340. It's in Dutch, but here is
what it boils down to :

Use a negative supply of -5V on pin 3 directly, and leave out the 820 ohm
resistor (REE in the original Curtis datasheet).
I used a small 79L05 stabilizer to derive -5V from the -15V supply.
In the dual VCO design for the Aemit, I took no risks and used a separate
79L05 for each VCO on the PCB.

If you want all the details I can translate the whole memo in English, but
chances are the original memo was in English anyway (haven't seen it though).

I've asked this before, here goes again : is it possible to get this list
in digest form ? I'm getting ennoyed with all these separate mails.

 Wim Verheyen
 catwim at innet.be
 belkurz or kurzbel on undernet irc

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