Measuring and modeling the effects of substrate noise on the LNA for a CMOS GPS receiver

The influence of substrate noise coupling on the performance of a low-noise amplifier (LNA) for a CMOS GPS receiver has been investigated both analytically and experimentally. A frequency-domain approach has been used to model both noise injection into the substrate from digital circuitry integrated on the same chip and the mechanisms by which that noise can affect analog circuit behavior. The results of this study reveal that substrate noise can modulate the LNA input signal as well as couple directly to the amplifier's output.