Measuring and modeling the effects of substrate noise on the LNA for a CMOS GPS receiver
The influence of substrate noise generated in a digital circuit on the low-noise amplifier (LNA) of a CMOS GPS receiver has been experimentally characterized and theoretically analyzed. A frequency domain approach is used to model noise injection into the substrate from the digital circuitry and the mechanisms by which that noise can affect analog circuit behavior. The results reveal that substrate noise can modulate the LNA input signals as well as directly couple to the LNA output.