A Highly Sensitive Magnetic Hall Sensor with a Low Noise Integrated CCIA Interface Circuit

This paper presents a highly sensitive Hall sensor with a high-performance instrument amplifier interface circuit fabricated in a 0.18 mu m CMOS process. The Hall sensor is optimized with an equivalent model that achieves a high sensitivity of approximately 25.82 mV/VT under a magnetic field intensity of 60 mT. The instrument amplifier employs a capacitance-coupled instrument amplifier (CCIA), consisting of a chopper for noise reduction, a positive feedback loop for input impedance boosting, and a ripple reduction loop to suppress chopping ripple. Experimental results demonstrate that the CCIA achieves a gain error of less than 0.1% with a noise floor of 223 mu V/root Hz @ 4 Hz. The integrated testing system is suitable for tactile sensing, biological applications, and micro compasses.