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On 30 Nov 2005 14:32:29 -0800, wrote:

Jim Thompson wrote:
On Sat, 26 Nov 2005 21:41:06 +0100, Winfried Salomon
wrote:

Hello Jorgen,

Jorgen Lund-Nielsen wrote:

[.....]
2N2369 for fast pulses.

btw, do you know a standard complementary pnp-transistor for the 2N2369,
such like 2N3905 but with higher ft and less feedback capacitance? It
seems that the manufactorers have almost no data on their internet pages.

mfg. Winfried

A 2N2369 is a gold-doped NPN, gold-doped to kill storage time and
improve recovery from saturation. I don't recall any PNP device with
gold-doping... or the equivalent.

...Jim Thompson

National Semi's (now Fairchild) 2n5771 was a gold-doped PNP.
ft=850MHz. For avalanche mode one might try the lower-Vce-rated
PN3640 (12v), or PN3639 (6v).

I might even have notes on this. I tested/compared various BJTs in
avalanche mode some years ago, trying to find the "best." ISTR picking
the 2n2369, both because it was fast, and because it avalanched
reliably where other types wouldn't.

James Arthur

Hi, James,

Interestingly, the best avalanchers aren't usually super-fast
transistors, but old klunky things. The Zetex avalanche transistors
have lowish Ft's and are made in Russia, maybe on an old process.

John