A 107 pJ/b TX 260 pJ/b RX Ultralow-Power MEMS-Based Transceiver With Wake-Up in ISM-Bands for IoT Applications

Abstract

This article presents an ultralow-power (ULP) microelectromechanical system (MEMS)-based phase-tracking frequency shift keying (FSK) transceiver (TRX) with an embed- ded envelop detector-based on–off keying (OOK) wake-up receiver (WuRX). The system supports a shared antenna interface of FSK-matched filter for TRX and a matching network for the FSK receiver (RX) and OOK WuRX. To consume less power, the transmitter employs an adaptive fast switching (AFS) technique for FSK/OOK modulator and uses a high-Q MEMS resonator to get frequency stability. In addition, for better interference filtering, the MEMS-based modulator is shared to provide LO in FSK RX as it owns inherent sidelobe suppression. To support higher blocker/interference rejection with relatively low power, MEMS-based FSK-matched filter plus matching network with current-reuse LNA is co-designed to provide additional passive gain. Fabricated in 65-nm CMOS process, the transmitter (TX) generates FSK signals of −11.2 dBm output power at ISM- 915 MHz and the data rate is up to 6 Mb/s. At 1 MHz offset, the measured phase noise (PN) is −140.2 and −139.3 dBc/Hz at 926.3 and 932.4 MHz, respectively. By sharing the modulator, the RX exhibits −36.2 dB in-band signal-to-interference ratio (SIR), −77.5 dBm sensitivity at bit error rate (BER) of 10 −3 working under 2 Mb/s data rate. The TX, FSK RX, and WuRX consume Manuscript received 22 March 2022; revised 1 August 2022 and 20 September 2022; accepted 21 September 2022. Date of pub