Suppression of Digital Noise Coupling on LNA in 0.13-μm RFCMOS Technology by Global Guard Rings

Digital noise coupling on the noise-sensitive RF and analog circuits through substrate continues to grow as a critical issue as the on-chip integration of digital and RF/analog becomes increasingly popular with the advent of SoC approach. In this work, the effect of digital noise coupling on a 5.8-GHz LNA in 0.13 mum RFCMOS technology was investigated in terms of the noise figure. The noise figure degradation was compared for various magnitudes and clock frequencies of the digital signal applied. Further, the suppression of the noise coupling on the LNA by the global guard ring was demonstrated and compared for various guard ring bias schemes.