Re: gEDA-user: ngspice shot noise

[Karel Kulhavy <clock@xxxxxxxxxxxxx>]

On Wed, Sep 28, 2005 at 08:17:24AM -0400, Dan McMahill wrote:
> Karel Kulhavy wrote:
> >Hello
> >
> >Does ngspice noise model also work for operation of BJT with extremely
> >small collector current?
> >
> >I got an idea to make low-noise amplifier by taking some 25GHz
> >transistor and powering it with so small collector current that its
> >transition frequency would drop down to 300MHz and then using it in
> >Ronja preamplifier instead of 2N3904. As second or even first stage
> >of the preamp.
> 
> Why use an RF transistor?  The only reason I'd see for this is if 
> thermal noise due to base resistance were your limiting factor.

Because only RF transistor has transition frequency of 25GHz.

CL<