MEMS-based all-digital frequency synthesis for ultralow-power radio for WBAN and WSN applications

This paper explores the use of MEMS devices such as bulk acoustic wave (BAW) and low frequency silicon resonators, in combination with digital circuits and techniques, to reach miniaturization and low power dissipation in a 2.4 GHz transceiver targeting wireless body area networks (WBAN) and wireless sensor networks (WSN) applications. Precise phase locking of the BAW digitally controlled oscillator (DCO) to the low- frequency temperature compensated oscillator is demonstrated. Additional cancellation within the ADPLL of the deterministic jitter induced by the bi-frequency mode on the 32 kHz clock is proven, with a residual modulation on the DCO command word corresponding to ±0.5 ppm relative frequency deviation. The RF resulting after frequency up-conversion of the system IF signal with the DCO shows an excellent phase noise of - 136.6 dBc/Hz at 1 MHz offset frequency, for a total synthesizer current consumption of 7.52 mA under 1.6 V supply. In addition, 1 Mb/s GFSK Bluetooth and Bluetooth Low Energy modulations have been successfully validated in transmission.