Low-voltage CMOS analog bootstrapped switch for sample-and-hold circuit: design and chip characterization

This paper presents the design and characterization of a sample-and-hold circuit based on a novel implementation of the bootstrapped low-voltage analog CMOS switch. The heart of this circuit is a new low-voltage and low-stress CMOS clock voltage doubler. Through the use of a dummy switch, the charge injection induced by the bootstrapped switch is greatly reduced, resulting in improved sample-and-hold accuracy. Experimental results in a 0.18 μm digital CMOS process show that a resolution greater than 10 bits can be obtained with a 1.0 V supply voltage. Circuit operation is also possible for supply voltages close to the transistor threshold (e.g., 0.65 V).