Suppression method of low-frequency noise for two-dimensional integrated magnetic sensor

A new correlated double sampling method for two-dimensional magnetic sensors was proposed. In this method, output from a magnetic sensor is controlled by adjusting the drain bias of a MOSFET used as a Hall element. The two-dimensional integrated magnetic sensor used for the demonstration of correlated double sampling was composed of a 64 × 64 array of Hall sensors and fabricated by a 0.18 µm CMOS standard process. The size of a Hall element was 2.7 × 2.7 µm2. The dimensions of one pixel in which a Hall element was embedded were 7 × 7 µm2. The magnitude of residual noise after correlated double sampling with drain bias control was 0.81 mVp-p. This value is 16% of the original low-frequency noise. From the experimental results, the proposed correlated double sampling method is found to be suitable for low-frequency noise suppression in the two-dimensional magnetic sensors.