PNP Matched Pairs

[Grant Richter]

They are nice transistors. I am going to use the THAT160 in
a dual state variable I am working on. The bulk resistance is
rather high, 2 ohms, compare to 1.5 ohm for a LS358 and 0.3 ohm
for a SSM2220. For a VCO you want that Rbe figure as low as possible.
The 1.5 ohm figure of a LS358 will put the oscillator almost a
semitone flat at three octaves above middle C.

Now you can compensate for that with a resistor in front of the
timing cap. But the SSM2220 shouldn't need compensation at
all.

These should work just fine for filters and such with relaxed
requirements. The THAT160 is equivalent to two matched 2N3904
and two 2N3906 transistors in one package. A perfect fit for the
Electronotes state variable designs.

----------
> From: Paul Maddox <space_banana at hotmail.com>
> To: steve.ridley at bbc.co.uk
> Cc: synth-diy at mailhost.bpa.nl
> Subject: RE: PNP Matched Pairs
> Date: Monday, July 12, 1999 2:55 AM
> 
> Steve,
> 
> >
> >Has anyone tried the That Corporation transistor arrays.  They do
> >4 x NPN, 4 PNP, 2 NPN + 2 PNP and 4 NPN + 4 PNP arrays,
> >all 25v, 10mA, matched to 500uV. See...
> >
> >	http://kiosk.std.com/Newbury/thatcorp/icprod.htm
> >
> 
> 
> Nope, never even h=eard of them (didnt they used to make audio tape?)
> 
> Anyone know if these are ok for Log convertors...
> they seem ok to me, but Im not too hot with transistor characteristics.
> 
> Paul
> 
> 
> 
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