Circuit Techniques for Reducing the Effects of Op-Amp Imperfections: Autozeroing, Correlated Double - Proceedings of the IEEE

In linear IC's fabricated in a low-voltage CMOS technology, the reduction of the dynamic range due to the dc offset and low,frequency noise of the ampli$ers becomes increasingly significant. Also, the achievable aniplijier gain is often quite low in such a technology, since cascoding may not be a practical circuit option due to the resulting reduction of the output signal swing. In this paper, some old and some new circuit techniques will be described for the compensation of the amplifier most important nonideal effects including the noise (mainly thermal and l l f noise), the input-referred dc offset voltage, as well as the finite gain resulting in a nonideal virtual ground at the input.