[sdiy] mached transistors

[Scott Bernardi]

Actually in the LM3046 all the transistors are matched,  it's just that two of
them are connected as a differential pair (emitters tied together).

Theo wrote:

> Only the pairs have to be matched, the closer the better.
> For a ladder its enough to have the top and bottom pairs matched.
> But matching all pairs does give slight a improvement.
> Using LM3046 ICs is also an alternative,
> each IC contains one matched pair and 3 separate transistors.
>
> Theo
>
> From: Terje Winther <terje.winther at notam02.no>
>
> > Hello,
> > I am measuring some transistors to get "mached transistors" needed for
> some
> > VCFs (moog-ladders) and VCAs.
> > How close do they have to be to be called "matched"?
> > totally equal? 1% apart? 2% 3-5%?
> > Also, for the moog-ladder filters; do they have to be matched between the
> > ladder "staps", or is it enough to have the two transitors of each "step"
> > to be matched?
> >
> >
> > tw.  :)
> >
> >

--
Scott Bernardi
sbernardi at attbi.com