A 1.3 mW, 12-bit lock-in amplifier based readout circuit dedicated to photo-acoustic gas sensing

This paper discloses the implementation of a 12-bit Lock-In Amplifier (LIA) based readout circuit dedicated to Photo Acoustic gas sensors. The LIA is fully integrated as it embeds the low pass filter, the clock generation circuit as well as a 12-bit ADC. It has been implemented in a 0.35 μm CMOS technology. Its power consumption is 1.3 mW under a 3.3 V supply voltage, while achieving a 10 nV/sqrt(Hz) input referred noise. The measured readout circuit linearity is 1.7%.