A 3.6mW 90 nm CMOS 2.4 GHz receiver front-end design for IEEE 802.15.4 WSNs

In this paper a low-power design of an integrated RF receiver for Wireless Sensor Networks (WSNs) in 90 nm CMOS technology is proposed. The receiver is IEEE 802.15.4 physical specifications compliant. It is designed to operate in ISM band at 2.45 GHz center frequency. Target devices for this kind of transceiver are low-cost battery powered smart embedded devices and sensors. The receiver is designed to reduce the count of external components in the final system, integrating on silicon the balun for single-ended to differential conversion. The receiver is composed of an inductorless Low Noise Amplifier (LNA), a buffer stage, I and Q passive mixers and Variable Gain Amplifiers (VGAs) that also act as second order filters. A novel integration of balun into the LNA is described. The system is designed to have direct conversion from RF to 6 MHz low-IF. Voltage supply is 1.2 V with a current consumption of 3 mA including necessary biasing networks, and the total power consumption is 3.6 mW. The complete voltage gain is more than 41.5 dB with a Noise Figure (NF) of 12.6 dB. The receiver layout exhibits an area of only 0.12 mm². Simulations are provided, including mismatch scenarios.