MODELING OF SUBSTRATE NOISE IMPACT ON A SINGLE-ENDED CASCODE LNA IN A LIGHTLY DOPED SUBSTRATE

Substrate noise generated by digital circuits on mixed-signal ICs can disturb the sensitive analog/RF circuits, such as Low Noise Amplifier (LNA), sharing the same substrate. This paper investigates the adverse impact of the substrate noise on a high frequency cascode LNA laid out on a lightly doped substrate. By studying the major noise coupling mechanisms, a new and efficient modeling method is proposed to predict, prior to processing, the LNA performance degradation due to the substrate noise. Our simulations prove that the model can estimate the magnitude of the spurious signals appearing at the output spectrum of the 5 GHz LNA, within an acceptable error of 13%.