A CMOS Single-Chip Electronic Compass with Microcontroller

A CMOS single-chip electronic compass with a 16b DSP for heading calculation is presented. A Hall-based 3-axis magnetic-field sensor and analog amplifiers, with a gain of up to 20,000, drive a 12b ADC. A 0.35mum low-voltage CMOS process is used with an added metal layer working as a magnetic-field concentrator with a gain of about 6 to 10. The chip works with a 2.2 to 3.6V supply and draws 5mA in normal mode. The heading resolution is better than 0.5deg and the accuracy is better than plusmn2deg