A low power fully differential RF receiver front-end for 2.4GHz wireless sensor networks

In this paper, a novel merged LNA-mixer denoted as LNMA is proposed. The proposed LNMA consisting of a folded cascode LNA using improved derivative superposition technique and folded double-balanced subthreshold mixer using capacitor cross-coupled common-gate transconductor and it is integrated with on-chip LC voltage controlled oscillator (LC-VCO). In LNMA, a diode and power clamp based on-chip ESD protection circuit is used to tolerate ESD current of human-body-model specifications. To evaluate its performance, it is implemented in 0.18-mu m MMRF CMOS process with 1-V supply, studied through post layout simulation and compared the results with other reported works. It achieves higher conversion gain of 27dB, lower noise figure of 9.5dB, lower input return loss (S11) of -20dB, higher third-order input intercept point (IIP3) of -16dBm and higher IIP2 of +29.9dBm compared to the works reported in the literature. The on-chip oscillator has the lower phase noise of -114dBc/Hz. The proposed LNMA and the LC-VCO achieves the power consumptions of 1.6 and 1.72mW, respectively at 1-V power supply.