[sdiy] SMT noise generation?

David G Dixon dixon at mail.ubc.ca
Mon Aug 13 18:59:48 CEST 2012

>      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?

Sounds like one of those "suck it and see" scenarios to me.  You could
always line up a few in parallel...

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