Multipath Wide-Bandwidth CMOS Magnetic Sensors

This paper proposes a multipath multisensor architecture for CMOS magnetic sensors, which effectively extends their bandwidth without compromising either their offset or resolution. Two designs utilizing the proposed architecture were fabricated in a 0.18- mu m standard CMOS process. In the first, the combination of spinning-current Hall sensors and nonspun Hall sensors achieves an offset of 40 mu T and a resolution of 272 mu T-rms in a bandwidth of 400 kHz, which is 40 times more than previous low-offset CMOS Hall sensors. In the second, the combination of spinning-current Hall sensors and pickup coils achieves the same offset, with a resolution of 210 mu T-rms in a further extended bandwidth of 3 MHz, which is the widest bandwidth ever reported for a CMOS magnetic sensor.