The Switched-Capacitor Integrator [A Circuit for All Seasons]

In the 1970s, CMOS technology was finding its way into analog design through switched-capacitor circuits. The availability of simple switches and highimpedance nodes in CMOS afforded more efficient sampling and holding of signals than in bipolar technologies. The switched-capacitor integrator was a versatile function developed in that era as a building block for filters, but it later found usage in such systems as DR modulators as well. In this article, we study the operation and properties of this circuit.