A 0.7 v, ultra-wideband common gate lna with feedback body bias topology for wireless applications

Abstract

An ultra-wideband (UWB) low noise amplifier (LNA) for 3.3–13.0 GHz wireless applications using 90 nm CMOS is proposed in this paper. The proposed LNA uses an improved common-gate (CG) topology utilizing feedback body biasing (FBB), which improves noise figure (NF) by a considerable amount. Parallel-series tuned LC network was used between the common-gate first stage and the cascoded common-source (CS) stage to achieve the maximum signal flow from CG to CS stage. Improved CS topology with a series inductor at the drain terminal in the second stage connected and cascoded CS third stage provides high power gain (S21 ) and bandwidth enhancement throughout the complete UWB. A common-drain buffer stage at the output provides high output reflection coefficient (S22 ). It achieves an average power gain (S21 ) of 14.7 ± 0.5 dB with a noise figure (NF) of 3.0–3.7 dB. It has an input reflection coefficient (S11 ) less than −11.7 dB for 3.3–13.0 GHz frequency and output reflection coefficient (S22 ) of less than −10.6 dB with a very high reversion isolation (S12 ) of less than −72.4 dB. It consumes only 5.2 mW from a 0.7 V power supply.