I. Introduction
Switched capacitor circuits have dominated instrumentation readout circuits for over three decades. During this time, the advancement of MEMS technology required integrated circuits capable of amplifying and converting all kinds of low level signals. Such MEMS sensors combined with instrumentation amplifiers and switched capacitor ADCs have enabled the inclusion of sensing capabilities in portable devices (e.g. cellular phones and wearables), see Fig. 1(a). A vast knowledge base has been built around this combination in or CMOS technologies at supply voltages above 1.2 V. However, as technology nodes and supply voltages scale down, switched capacitor circuits become increasingly problematic. This is because the switch overdrive voltage is very low and poor opamp DC gain in modern nanometer CMOS processes. This imposes limits on the resolution and power consumption of switched capacitor oversampled data converters.