An 18 nW −47/−40 dBm Sensitivity 3/100 kbps MEMS-Assisted CMOS Wake-Up Receiver

Abstract

This work demonstrates a low-power wake-up receiver utilizing a MEMS resonant device followed by CMOS demodulator and rectifying trigger circuits. The MEMS device is a Lamb wave piezoelectric-based acoustic resonator utilizing a thin film of lithium niobate (LN) which possess the largest reported electromechanical coupling factors (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ). This parameter, in conjunction with the high Q, is of paramount importance in providing for passive voltage amplification and filtering of the input signal. The CMOS demodulator is a 9-stage differential cross-coupled passive rectifier circuit designed with a differential output. It demodulates the signal from the MEMS resonator with the same gain as that could be achieved by a single-ended rectifier, but with half the charging time for double the single-ended bitrate. The rectifier's output is AC-coupled and fed to a two-stage differential voltage amplifier. Finally, an active latch rectifier is used to trigger a wake-up signal. The wake-up receiver is tested with an on-off keying modulated signal with carrier frequency around 400 MHz achieving a bit rate up to 100 kbps. This newly proposed system exhibits a sensitivity of -47 dBm at 3 kbps while consuming a total power of 18 nW.