This paper reports a monolithic device integrating a CMOS analog front-end and an array of 192 MR sensors for biomolecular recognition detection. Innovative CMOS building blocks (i.e. current source, multiplexers and pre-amplifier) were designed targeting a negligible noise when compared with the MR sensors noise and a low power consumption. The CMOS front-end was fabricated using AMS 0.35 μm technology and the magnetoresistive sensors were post-fabricated on top of the CMOS chip. Due to its low noise (16 nV/√Hz), the full system was able to detect magnetic nanoparticles with a SNR degradation of only 1.4 dB (circuit imposed). Furthermore, the unprecedented low power consumption (6.5 mW) and small dimensions (7.59 mm2) of the presented solution guarantees the portability of the detection system allowing its usage at the point-of-care.

This paper describes how magnetoresistive materials can be optimized and integrated in magnetic field sensor devices. Giant magnetoresistive (GMR) and tunnel magnetoresistive (TMR) can provide advantageous solutions for a wide range of applications, of which some are described here. Considerations on field sensitivities, intrinsic noise mechanisms, biasing, and integration schemes are presented.

This paper presents a recently developed handheld biochip-based microsystem. The microsystem is based on a magneto-resistive array biochip composed of a number of sensing sites with magnetic tunneling junctions (MTJ) and diodes. To drive the MTJ, different techniques are addressed with different types of signals. Filtering strategies are also presented, which allow the recovery of bio signals from the noise without increasing too much nor the time required to access all the sensors, nor the power consumption of the board. In conclusion, experiments with the system in a setup to detect actual bio signals are presented with encouraging results.