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Beta degradation quantified?

P

Phil Hobbs

Jan 1, 1970
0
John said:
I've heard of that. The real limit is that the average switching event
zots out far less than one average photon, so only sampling-scope type
data can be collected, and that very slowly. Are you using an mcp or
something behind the spectrometer?

John
Generally it's done by scanning, using a single-point detector such as a
superconducting bolometer or PMT. I'm not a PICA expert, people just
send me their summer students. ;)

Cheers,

Phil Hobbs
 
F

Fred Bloggs

Jan 1, 1970
0
Jim said:
[snip]

[snip]

Yep, I remember Ki Dong Kang. We were observing unexplained
alternator regulator failures.

...Jim Thompson

Since we know that hFE degradation is accompanied by a similar increase
in IEBO, this probably means that transistors designed for inverse
operation such as in chopper applications , like the MPS-A16/-A17, are
impervious to the effect due to VEB stress shy of avalanche. ON no
longer makes those, but they do have the MSD1328 with a VEBO of 12V, and
it seems a bit more rugged too, available in small quantity from Mouser
at low cost.
 
D

David DiGiacomo

Jan 1, 1970
0
There ARE diodes protecting the inputs of an SN7400.

I guess Jim wasn't paying attention when he wrote that. Later 7400 series
designs have clamp diodes to ground. However, Spehro was asking about
clamp diodes to Vcc to keep the emitter inputs from breaking down. They
can't be used because 7400 series parts have a maximum input spec of 5.5V
regardless of Vcc.

However, I don't think gold doped parts such as 7400s suffer from much
degradation. Maybe someone could test this with a 2N2369.
 
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