Bill Sloman said:
Popcorn noise comes from an extra random carrier traversing the base
region, usually seen in "super-beta" devices with push-ahead emitters,
thus an ultra-narrow base region.
So I'd tend to lump it in with shot noise.
So how come the old 709's and 741's were notorious for pop-corn noise?
They pre-dated super-beta transistors by a few years, and some 741
parts were still demonstrating the problem in 1988.
Back in 1970, one of my co-workers was actually using the super-beta
LM308 as a low noise front end in a sonar system, where pop-corn noise
might have been embarassing.
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I used a lot of LM308's back then to do active filters at 1/30Hz and
1/7Hz in a
system where any popcorn noise would have been _very_ obvious. I never
saw any signs of that kind of noise with that part.
As to how to minimise it, change manufacturers.
Regards
Ian