The Bootstrapped Switch [A Circuit for All Seasons]

Field-effect transistors (FETs) have been used as switches, particularly for analog signals, since the 1950s. In the early days of analog sampling, it was discovered that such devices exhibit an input-dependent on-resistance, thereby introducing distortion. This issue can be resolved by ?bootstrapping,? a circuit technique that minimizes the switch on-resistance variation in the presence of large input and output voltage swings. In this article, we study the bootstrapped switch topology and appreciate its role in nanometer designs.