Ian says:
>Could someone please enlarge on the procedure of matching diodes, using
>simple multimeters, etc.?
I don't believe that there is a simple one.
You can match for forward voltage drop at full current; there, you should
get a match to better than 10, and probably better than 5 mV. But you really
need to measure the piv at say, 10 microamps and up to 2 kV or more.
Capacitance matching needs to be done at rated piv, but the real difficulty
will be reverse recovery time. However, I suspect that there will be a
correlation between piv, capacity and recovery time for devices from the
same diffusion batch. This is because devices from the same diffusion batch
will tend to have the same doping profile. (Notice I say 'tend' - you can
get variations across a wafer, let alone wafer to wafer) These sorts of
diodes aren't made by ion implantation, which gives very precise control
(well, as much as anything in semiconductor manufacture is precise!) of
doping profile
73
Peter G3RZP
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