[sdiy] Expo VCOs: some thoughts

[Neil Johnson]

Hi Tim,

> I've been thinking about volt/octave VCO performance. My customer wants a
> triangle core VCO with excellent tracking. And of course he wants it for
> $0.25, but that's another story. I started looking at expo VCO design from
> the standpoint of tracking. Typically there are two pieces to an expo VCO:
> the expo converter and the VCO core, and they can be looked at separately.
> I'm going to tackle the core side because that is where the problems are
> with triangle cores.

Define "excellent" in numbers.
Is the $0.25 per VCO?  And how hard is that requirement?
What technology is your customer able to use?  PTH or SMT?  SOIC or ballgrid?
If SMT, single or double-sided component population?
Does your customer really need a _V_CO?  Could they use a
digitally-controlled oscillator?
Does it really need to be a triangle?  And how good?  What is the end use?
Could the target application allow retunes during normal operation?

And so on...

Neil
-- 
http://www.njohnson.co.uk