Ok,
Both Roy and John A, have effectively suggested series HC Diodes or Low C
Varicaps.
John A has found some data for an older Motorola HC diode the MBD502 that
shows figures for Vf and VBr that are roughly similar in a roughly similar
package. Roy also suggests the possibility of a low capacitance varicap, I
suppose the way to tell would be to measure the capacitance verses reverse
voltage characteristic. If it was something like a MBD502 then the
capacitance would be pretty much constant at a low value, if it is a varicap
it could also have a low ish value but should be varying a bit. Any ideas on
a simple way to do this, I assume my classic multimeter cap range wouldn't
like a DC voltage and a diode across it, and the other simple way I can
think of of known L and a GDO seems a bit messy to measure possibly sub 1pf
values?

By the way just in case anyone else is interested the place I got these from
still says on their web site that they have some 82000 more which they are
selling for $AUS0.0055 each for 1000 minimum which comes to AUS$5.50 for the
1000 see item 31118 at www.rockby.com.au .

Paul VK3DIP



"Roy Lewallen" wrote in message
...
I doubt that it's two series zeners, since it's no trick to make a single
zener with that breakdown voltage.

The only application I know of for series connected diodes with that sort
of breakdown voltage is for high dynamic range mixers. But the pairs I've
seen in a single package have a third pin at the junction so you can also
use them for other applications.

I wonder if it might be a low-C varactor. The very low C ones might
possibly consist of two diodes in series -- the manufacturers don't give
any clues since they don't publish any data on the forward bias
characteristics. The breakdown voltage of low C varactors is in that
ballpark, and the packaging is consistent with that possibility.

Roy Lewallen, W7EL