[sdiy] SMT noise generation?

Magnus Danielson magnus at rubidium.dyndns.org
Mon Aug 13 19:49:52 CEST 2012

On 08/13/2012 06:53 PM, Joe Grisso wrote:
> Hello all,
>       I've got an analog noise generator design I'm fleshing out, and
> hit a bit of a wall. I'm reaching out to do a sanity check since my
> discrete engineering expertise is a wee bit rusty. The simple question
> goes: If I have a TO-92 BC547 and replace it with a SOT-23 BC847,
> since they are the same part and have the same parameters, would that
> mean they would generate the same amount of noise? Part of me says yes
> because all the other parameters (Hfe, Vce, Ic, etc) line up, but
> another part of me says that since it's in a smaller package and may
> use less material to achieve those properties that there would be less
> noise. Could anyone clear this up for me?

Less plastic around the same die.

For these "generic" transistors, detail in the die can vary over time, 
but packaging like this isn't making the large difference.


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