[sdiy] 2n2920 Matched NPN transistor

[Oren Leavitt]

Bryce Lanham wrote:
> Hi,
> 
> I was digging through a box of parts and found a small bag of 2N2920
> matched NPN pairs. Given their age, are they closely matched enough
> for use in an expo convertor? Anyone ever use these things and know
> how well they track?
> 
> Thanks,
> Bryce Lanham

Hi Bryce,

I have used 2N2920 NPN pairs and 2N3810 PNP pairs in the past in filter 
and VCO expo converters, current mirrors, etc.
These seem to work as well as the CA3046/83/86 arrays.
As listed in an old TI transistor/diode data book, the Vbe match on the 
2N2920 is spec'd at 3mV (1.5mV for 2N2920A) at 100uA.

- Oren