Hey Russell,

Never heard of these guys until a mfgr's rep recently told me about them.  
Perhaps one of their products might fit your needs...  www.semtech.com .

Cheers,
-Neil.



On Tuesday 31 May 2005 05:37 am, Russell McMahon scribbled:
> I'm probably about to offer the manufacturer both TL499 and CD40106
> based design and let them choose the one which works out cheapest
> overall. I'll publish versions of them both with a pointer here as
> they may be useful to others. The CD40106 (hex Schmitt inverter) has a
> nasty parts count but the IC is the dearest single part at about
> $US0.15 or less.  The TL499 design uses far less parts but the IC is
> several times dearer. Both give good quiescent current and OK overall
> performance. The CD40106 is probably more efficient due to the full
> CMOS oscillator. Potentially VERY low quiescent  with great care. I
> have also tried various discrete and IC approaches but all are either
> too high quiescent or too dear or too flaky under questionable startup
> conditions or samples not available to me here right now.
>
> > The problem with the low cost SMPS controllers is the
> > quiescent current. This was true 5 years ago and is less
> > true now. MC34063 is a quite an old product anyway.
>
> Very old. Excellent for higher power levels where leading edge
> effciency is not an issue. Driver stage is not at all nice inside with
> its darlington driver BUT using it to drive a FET removes the
> saturation issue and transforms it. Driving a FET was not something
> the makers ever envisaged "way back then".
>
> > The problem with those nice SMPS controllers from
> > Intersil/Maxim/AD/Linear/TI is the relative high cost.
>
> Typically 5 times as much as a MC34063 :-(.
>
> > OnSemi/Fairchild/National/IR may produce some cheaper
> > product. There are some new players from Asia whose
> > product are less know to the public though.
>
> These I'd be interested in but I need samples here NOW and they also
> need to be available in Taiwan soonish.
> Next time round maybe.
>
>
>                 RM


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