A CMOS Magnetic Hall Sensor Using a Switched Biasing Amplifier

Abstract

A compact CMOS magnetic Hall sensor that includes both a Hall plate and readout circuit is proposed. In order to achieve a low-noise and low-power operation, the sensor employs a switched biasing amplifier with a chopper. The prototype has been implemented and fabricated in a high-voltage 0.18 mu m CMOS process and occupies 0.624 mm(2). Owing to the switched biasing amplifier, the input-referred noise is reduced from 41 mu T root Hz to 25 mu T root Hz. The entire sensor consumes 4.5 mW with a 3.3 V supply voltage.