Highly linear CMOS subthreshold four-quadrant multiplier for Teager Energy Operator based Sleep Spindle detectors

This paper presents a subthreshold four-quadrant multiplier targeted for Teager Energy Operator (TEO) based Sleep Spindle detecting circuits. The proposed highly linear multiplier operates on balanced input-differential output signals at a 1.2 V supply. The multiplier is tested using 90 nm CMOS process of the BSIM3v3.3 model in Cadence Virtuoso. The simulation results prove an input dynamic range of ±240 μV with negligible non-linear deviations and zero offset. The Total Harmonic Distortion (THD) is shown to be less than 5% under 40 μV AC at 11 Hz. The third-order Input Intercept Point (IIP3) is at −22.6849 dB m. The bandwidth of the multiplier is 14.4544 MHz with stand-by power 82.14 nW. The stability of the proposed circuit was also tested using the same technology in LTSpice XVII for PVT variations.