[sdiy] Temperature stable lin-exp converter with a CA3086or CA3046

[Gene Stopp]

Yes - that was my experience!! I wasn't really an advocate of the "don't buy
it" approach because I got it to work with the divider method...

I'm trying to remember if I put a scope on it - I seem to remember that
oscillation due to inductance was the first thing I thought of, and looked
and didn't see any, and just moved on... could have been probe capacitance
but at the time I didn't pursue it.

Best Regards,

- Gene


-----Original Message-----
From: Tom May [mailto:tom at tommay.net]
Sent: Wednesday, May 29, 2002 10:56 AM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Temperature stable lin-exp converter with a CA3086or
CA3046


Ian Fritz <ijfritz at earthlink.net> writes:

> >Certainly for op-amps, inductors in the feedback path is bad news (unless
> >you specifically design for it) as it can lead to loop instability, such
> >as overshoot.
> 
> Unless the resistor is wound non-inductively. I can't imagine why this
> would not be done. Has anyone actually seen this inductive effect?
> I've had no problems with the old Q81's, but it is certainly something
> to look at when ordering a tempco.

I was pretty sure somebody here had problems with inductance a while
back.  Turns out it was Christopher List in 1996:

http://www.buchi.de/sdiy/ShowPost.ASP?2494
http://www.buchi.de/sdiy/ShowPost.ASP?2542

Tom.