RobG wrote on Mar 24th, 2012, 8:18am:I wondered about that when I looked into something that would counter IS variations many years ago. Do you use the pinched resistor to determine the current in the BJT? Doesn't the Nwell also have similar correlation?
...
My guess is that if you talk about the physical sizing of the resistor you're probably not far off with N-well only resistor. I guess the difference is in the actual concentration level in the N-well. With the P+ implants of the emitter you probably change the concentration of the N-well too, which you cover when you take the pinched resistor model.
For me it's also a while ago that I've seen those devices. I just checked some of the (MOS) processes I use currently, but no pinched resistor in there.
Nice topic btw