Design Of A Sigma-Delta DAC In Magnetometer

MEMS(Micro Electromechanical System) with the characteristics of high integration, high reliability and low cost inherent, has been continuously developed, since its emergence. Due to the deepening digital process, MEMS sensor IC digital performance also allowed in theory has been greatly improved. Sensor magnetometer MEMS fields, the system architecture of its digital structure must be used for the high-precision sigma-delta DAC. Therefore, the design of a suitable magnetometer sensor digital structure sigma-delta DAC, has a great significance on both theory and application.The subject comes from Harbin Institute of Technology MEMS Center. This can be studied as a sigma-delta DAC digital magnetic sensor formed an important part of the future but also to improve improvements to applications that require micromechanical gyroscope sensor circuit.This paper introduces the whole sigma-delta DAC works and the structure and composition of each module, and later on the principle of each module basic exposition. The main principle of the digital interpolation filter, a digital modulator principle as well as the analog part are briefly described. After that, this paper design sigma-delta DAC digital interpolation filter, sigma-delta digital modulator, DWA module, the lower DAC and analog low-pass filter.Then a sigma-delta DAC digital-analog hybrid simulation is completed. The simulation waveform obtained Fourier spectrum analysis system harmonic component is about-100 d B, the output signal to noise ratio of 99.8d B, more than 16 significant digits.Finally, the layout design of digital part and analog part are completed respectively.