Does anyone have any experience of simulating noise performance with SPICE?
I'm playing around (in Tina-TI) with an old discrete audio preamp design that was originally intended for use with a pickup coil (moving-coil). If I ask for the input-referenced noise, it gives me this
That looks quite plausible, with the 1/f noise in place and a sensible level for the white noise (1 or 2 nV/rtHz - higher than a very good bipolar low-noise op-amp, but still quite respectable). One thing I'm unsure of is the low corner frequency. An OP27 would be around 2.5Hz, and that's very, very good, so a third of a Hertz looks too good to be true, although this design does use a medium-power transistor in a common-base arrangement at the input, which is obviously something the chip people can't do.
Would it be reasonable to expect transistors to have sensible noise figures in their models?
