Dual-channel bootstrapped switch for high-speed high-resolution sampling

A novel low-voltage CMOS bootstrapped switch has been designed. In this switch, a PMOS-type bootstrapped circuit combining with an NMOS-type one forms a dual-channel sampling switch that transmits the input signals to the output. Because of this parallel structure, the variation of on-resistance, owing to the variation of the gate overdrive and the threshold voltage, is greatly reduced, exhibiting gain in the sample-and-hold accuracy and linearity. The design was realised in an SMIC 0.18 µm CMOS process and its greatly improved dynamic performance was measured.