[sdiy] Analog division

[Harry Bissell]

I've done the divider with the LM13600, CA3080, and the CA3280.

I would not recommend anything other than the CA3280, which sadly 
is not only obsolete, but plagued with counterfit parts as well.
(and expensive now..)

To get stability with the CA3280, I needed to use a small cap across
the opamp from output to inverting input. So small, in fact, I used
a "gimmick" capacitor to fine tune the response :^)

(reference not added for amusement of younger DIY'ers who may not
have ever heard of such a thing. Next week we will discuss "Muntzing")

The AD633 might not be a bad choice, really.

I'm thinking of the SSM2164 as well... it looks like it could go 
in an opamp feedback loop.


----- Original Message -----
From: Paul Perry <pfperry at melbpc.org.au>
To: synth-diy at dropmix.xs4all.nl
Sent: Fri, 16 Jul 2010 18:49:38 -0400 (EDT)
Subject: Re: [sdiy] Analog division

You can make a cheap multiplier from an OTA - such as half a LM13600 - 
good to within a couple of %. Maybe you could put that inside the loop,
the LM13600 operates up to a pretty high frequency.

If you are using it to control amplitude, it should be close enough.
Less than an order of magnitude worse than the AD633 - which 
doesn't look all THAT bad in singles. Now when you buy a hundred,
that really hurts!

paul perry Melbourne Australia
_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy

-- 
Harry Bissell & Nora Abdullah 4eva