[sdiy] SSM2220 Sources

[patchell]

    Probably easier to get MAT-03's

Nick Liebrecht wrote:

> Hi,
>
> Does anyone out there know where I can get some SSM2220s matched PNP
> transistor pairs?  I can't seem to find them here in the USA.  I don't need
> many.  Is anyone willing to sell me two or three?
>
> What are the parameters that I need to look at for use in exponential
> converters?  Are there any suggestions for substitutes?

    Bulk Emmitter Resistance, Rbe, is one...and Delta Vbe are probably two of
the more important....it is actually rather surpising just how bad they can be
sometimes...I get pretty good performance from a CA3046 (this is an NPN array)
over 8 octaves.

    Also, take a look at these:http://www.thatcorp.com/datashts/300data.pdf

    I have used their earlier arrays...very nice.

>
>
> Any assistance would be appreciated.
>
> Thanks,
> Nick Liebrecht

--
 -Jim
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