CMOS oversampling ΔΣ magnetic to digital converters

Abstract

In this paper, a CMOS oversampling delta sigma (AX) magnetic to digital converter (MDC) is proposed. In the MDC, the magnetic operational amplifier (MOP) combines with the switched capacitor (SC) AX modulator, and converts the external magnetic field into digital form. Simulation and measurement results indicate that the average digital output versus the applied magnetic field is quite linear. The prototype circuit was fabricated in a 0.5um CMOS DPDM process. The circuit operates at a 5V supply voltage and the sampling rate of 2.5MHz. The maximum signal range of the converter is at least +10OuiT and the resolution can reach as small as ImT. The gain error within f100niT is less than 3%. The conversion gain is 1.327mv/mT and the power consumption is 49.3mW.