Low-frequency voltage mode sensing of magnetoelectric sensor in package

An in-package voltage-sensing integrated magnetometer for low frequency neural recording at room temperature is presented. The detection system consists of a voltage mode CMOS amplifier with an active biasing circuit and a Metglas/Polyvinylidene fluoride (PVDF)-based magnetoelectric (ME) unimorph sensor measuring 10 × 3 × 0.025 mm in volume, representing the smallest ME sensor volume reported to date. Over the frequency range of interest (0.5 Hz–1 kHz), both theories and experiments are in excellent agreement and the fabricated magnetometer exhibits a frequency independent signal-to-noise ratio (SNR) at the system level. The magnetometer achieves a SNR of 3000 and detects a minimum detectable field of 30 nano-Tesla waveform. This system in package provides a feasibility demonstration of integration of ME sensors directly with NMOS readout electronics aimed at tiny magnetic field detection for bio-imaging applications.