A 1 GHz linearized CMOS track-and-hold circuit

A simple solution for linearization of the MOS sampling switch is proposed. It improves the SFDR of a T/H circuit and is suitable for high-speed applications. Sampling at a constant gate-source voltage minimizes sampling errors due to variable MOS sampling switch ON-conductance and channel charge injection, and also eliminates input-dependent sampling instant variation. The proposed linearized T/H circuit is fabricated in a 0.35-/spl mu/m CMOS process. Test measurements show the sampling of a 1 GHz signal.