Integrated Circuit for Super-Regenerative Low-Frequency Amplification

An improved topology for the baseband super-regenerative sampling amplifier is proposed and analyzed, which employs a series-capacitors output load to realize positive feedback. As in the conventional circuit, the gain of the amplifier is continuously variable by controlling the length of the capacitor charging phase. It is shown that decreasing feedback enhances the linearity of the circuit while trading off with a lower sampling speed. Entirely removing the feedback yields the integrating amplifier circuit. This is a practical implementation in terms of linearity, power, noise, and gain in low-frequency applications, including biomedical signal amplification. The analysis is verified by measured results from an integrated circuit prototype in 180-nm CMOS technology.