Design of current reuse based Differential Merged LNA-Mixer (DMLNAM) and two-stage Dual Band LNA with two gain modes in 65nm technology

Abstract

In the radio frequency (RF) front-end, LNA with good noise figure without degrading performance a very important component to be developed. This paper presents design of two topologies of current reuse based Low Noise Amplifier (LNA) with low noise figure. LNA1 describe the fully integrated narrow band Differential Merged LNA-Mixer (DMLNAM) with two current reuse paths and LNA2 describes fully integrated Two stage Dual Band Low Noise Amplifier (DB-LNA) for 1.8GHz and 2.4GHz with two gain modes (high gain mode, low gain mode) in 65nm technology. The proposed DMLNAM(LNA1) employ first current reuse path to achieve low power, high gain and low noise figure and second current reuse path for narrow band load tuning and gm stage of Mixer is stacked on the top of CMOS LNA. In the proposed Two stage DB-LNA(LNA2), first stage employs a varactor for dual band input matching with self-biasing technique, current reuse structure to achieve high gain, low noise figure and low power consumption. Second stage employs current splitting technique to switch between two gain modes. Differential Merged LNA-Mixer features gain of 26.64dB with noise figure of 1.61dB@10MHz, 1.62dB@1MHz and 1.77dB@100KHz. In high gain mode (SW1=0V) of Two-stage Dual band LNA(LNA2) with two gain modes have a gain of 21.1dB, 19.61dB with a noise figure of 1.739dB, 2.22dB at 1.8GHz and 2.4GHz respectively. In low gain mode (SW1=1.2V), the Two stage DB-LNA features a gain of 12.15dB and 10.6dB and a noise figure of 2.36dB and 3.51dB at 1.8GHz and 2.4GHz respectively. The DMLNAM (LNA1) and Two stage DB-LNA circuit consumes 16.5mW@1.5V and 11mW@1.2V respectively.