Things are getting out of hand !
- I recently started #AMBAP: A Modest Bitslice Architecture Proposal : this is a sort of framework where I can examine and compare different technologies, with the goal of performing one function (ALU+registers). This gives us a list of gates to design : AND, OR, XOR, MUX, latch, buffer...
One bitslice can be implemented with different types/references of transistors and their performance is compared easily.
- I'll get new tools soon : a 200MHz DDS and a 4×300MHz scope. Just in case ;-)
- I made a little inventory of the available (hoarded ?) germanium transistors: (the silicon ones are there ) Superseded by log 4. Inventory #2 ?
|KF167||NPN||?||250 ?||Tesla ?|
The G106T and AF137 are pretty much the same (same manufacturer, same characteristics...) and just a tiny bit slower than the AF138.
AF200 is quite faster but the power rating I have found feels inaccurate. The package is a classic-looking metal can, much smaller than the TO-5 of the AF178 rated at 75mW. In comparison, the slower AF13x are in the funny-looking "long can" TO-18 package.
Anyway, I have two sorts of transistors :
- 1600 medium-gain but slow PNP (hFE >60, Ft < 50MHz)
- 760 fast but lower gain PNP (hFE>20, Ft > 100MHz).
In the context of a bitslice, the fast transistors would be used for the adder's carry chain, while the slower would do the rest. Since they have a higher gain, they could be tuned to consume less current and save some energy (which will translate into less drift during operation ?)
Anyway, I can already imagine implementing one bitslice with each one of these references and see how the Ft (transition frequency) translates into raw operating speed.
Oh wait, today it seems I can get a ridiculous amount of AF240...
2020 : Jaromir sent me his stock of eastern germanium and this is getting crazy :-D
However the inventory is not easy...