Silicon Digital Pressure Sensor using Ring Oscillator and Mixer

摘要

A digital pressure sensor using ring oscillator and mixer is presented. The sensitive unit of this pressure sensor is MOS ring oscillators with frequency output. Mixer is used as interior signal processor in order to improve characteristics of the output signal. The pressure sensor has many perfect characteristics such as high sensitivity, low temperature coefficient and simple fabrication process. The frequency character of MOS ring oscillator and its relationship with pressure are described. The MOS ring oscillator, mixer circuits and physical structures of this pressure sensor are designed. The device was fabricated by standard IC process mixed with MEMS process. The sensitivity of fabricated devices is 1.52 kHz/kPa.