Effect of power supply imbalance on NF of CMOS low noise amplifier for UHF RFID applications

In this paper, noise figure (NF) degradation of CMOS low noise amplifier (LNA) for UHF RFID application, which is caused by power/ground noise (P/G noise) from power supply imbalance is analyzed. Then, a modified NF formula to estimate the effect of P/G noise from power supply imbalance is proposed. Because the power supply imbalance is caused by package (PKG) and on-chip power/ground distribution network (PDN) structure, PKG and on-chip PDN are modeled. Also, the equivalent circuit of LNA is modeled to simulate the proposed NF formula. The proposed NF formula is verified with measurement of single-tone and clock P/G noise. It shows 50m, 800MHz single-tone P/G noise at PKG PWR/GND port degrades about 120dB of NF at 800MHz.