[sdiy] Best CA3280 projects?

[Dan Snazelle]

Az.

Sent from my iPhone

On Jun 30, 2012, at 11:41 AM, Ian Fritz <ijfritz at comcast.net> wrote:

> At 05:55 AM 6/30/2012, Tom Bugs wrote:
>> Makes me wonder...
>> 
>> Would it be possible to make a very compact sub-board discrete CA3280 clone?
>> 
>> Anyone done any work on such areas?
> 
> Yes, I posted about this about 4-5 years ago, so you could probably find it it the arrchives.
> 
> I was shooting for performance comparable to the CA3280.  I eventually got there, but it wasn't easy.  Matching of the transistors is crucial.  The only thing that worked well enough was some of the  MATs -- Vbe matching to better than 50 uV.  Good matching is needed for both the current mirror and for the linearization diodes, if you want to include those.  The whole deal was very expensive.
> 
> Once again, matching for a balanced circuit is much more critical than for a VCO front end, where matching is only for temperature compensation, not electrical performance.
> 
> Ian 
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