A CMOS circuit for precise reading of matrix addressed magnetoresistive biosensors

This paper presents a CMOS circuit for precise reading of matrix addressed magnetoresistive biosensors. The reading precision depends on the resistance non-linearity of the MOS switches used to address each biosensor. We present a linearization technique of the switch “ON” resistance by using feedback to force the switch drop-voltage to be equal to an independent voltage source. This technique has been confirmed by simulation and experimental results, showing a significant improve in the Total Harmonic Distortion and in DC behaviour, with respect to switches without linearization. The test circuit was designed and fabricated in AMS 0.35 μm 3.3 V technology.