High sensitivity, low power, silicon magnetic field detector

A CMOS magnetic field sensitive oscillator is presented. The device is aimed at a very low power application, where small size is essential. When subjected to a 10 Gauss magnetic field, it registers a 3 Hz change in frequency, which is readily detectable and above the noise floor, while drawing only 100 nA from a 2 V supply. This represents a factor of thirty improvement in sensitivity over previously reported devices and the highest sensitivity/power ratio reported to date for a silicon magnetic field sensor.<<ETX>>