Low-power 2.4-GHz transceiver with passive RX front-end and 400-mV supply

An ultra low power 2.4-G-Hz transceiver targeting wireless sensor network applications is presented. The receiver front-end is fully passive, utilizing an integrated resonant matching network to achieve voltage gain and interface directly to a passive mixer. The receiver achieves a 7-dB noise figure and -7.5-dBm IIP3 while consuming 330 mu W from a 400-mV supply. The binary FSK transmitter delivers 300 mu W to a balanced 50-Omega load with 30% overall efficiency and 45% power amplifier (PA) efficiency. Performance of the receiver topology is analyzed and simple expressions for the gain and noise figure of both the passive mixer and matching network are derived. An analysis of passive mixer input impedance reveals the potential to reject interferers at the mixer input with characteristics similar to an extremely high-Q parallel LC filter centered at the switching frequency.