Residual charge on a switched capacitor [MOS type]

A simple semiempirical model is presented to estimate the residual charge (feedthrough error) on a switched MOS capacitor. The model ignores the complexities of changing channel resistance during the turnoff transient, treating the channel as a simple on/off switch. In spite of this simplification, the results agree with computer simulations over a wide range of parameters. The model is easily extended to more complex situations found in typical switched-capacitor circuits.