(updated 20161230)
(updated 20170106)
(updated 20170326)
supersedes log 1. Inventory?
So I got the 4-channels 200MHz DDS, the 4×300MHz scope, as well as a 2×200MHz DSO, and a new supply of AF240S.
Ref | hFE | Ft (MHz) | I (mA) | U (V) | P (mW) | Fab | Qty |
G106T | 60 | 35 | 25 | 60 | Telefunken | 300 | |
AF137 | 60 | 35 | 25 | 60 | Telefunken | 300 | |
AF138 | 60...100 | 40 | 25 | 60 | Telefunken | 1000 | |
AF178 | >20 | 180 | 10 | 25 | 75 | Philips | 100 |
AF200 | >30 | 200 | 10 | 25 | 225 (??) | Siemens | 600 |
AF240 | 25 | 500 | 10 | 15 | 60 | Siemens | 10000 |
AF439 | >10 | 400 | 10 | 15 | Philips | 540? |
I can now choose between 3 classes of Ge transistors :
- 1600 medium-gain but slow PNP G106T, AF137, AF138 (hFE >60, Ft < 50MHz)
- 700 faster but lower gain PNP AF178, AF200 (hFE>20, Ft > 100MHz).
- 10000 very fast, low voltage, low gain PNP AF240S
The slow transistors can be used for I/O ports. For example keyboard input, LED drivers, GPIO, serial I/O... Probably using saturated logic as well, whereas the AF240 will use ECL.
I wonder if I can make 25MHz synchronous counters. That would enable me to work with a VGA display, reusing some tricks implemented by @Ted Yapo for #PIC Graphics Demo.
No idea about how to implement some memory, though. I don't want to suffer the magnetic/core memory hell... I will certainly cheat and use modern CMOS ASRAM :-)
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