[time-nuts] TAPR TICC boxed (input protection)

Charles Steinmetz csteinmetz at yandex.com
Sat Apr 8 15:26:00 EDT 2017


David wrote:

> So gold doping does work with PNP devices.  Previously when I brought
> it up, I was told gold doping only applied to NPN devices leading to
> my confusion.

Since I posted, I dug through my books and found a few more references 
on point:

A couple of textbooks say commercial PNP fast switches are (were) Pt 
doped.

Motorola and National Semiconductor say they use(d) gold doping for fast 
PNP switches.  Section 6 of National's 1978 Discrete Databook ("Process 
Characteristics") lists 10 gold-doped processes (6 NPN and 4 PNP) and no 
Pt-doped processes.

Raytheon's Transistor Dice Catalog indicates that the company used gold 
doping for NPN switches (Processes CJ and CK) and Pt doping for PNP 
switches (Processes GJ, GK, and GR).

Raytheon sourced small-signal, high-speed PNP switches 2N2409, 2N2894, 
2N3640, 2N4208, 2N5771, and 2N5910 from its platinum-doped Process GR. 
National sourced these parts from its gold-doped Processes 64 and 65.

Best regards,

Charles




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