Sense amplifier including multiple conduction state field effect transistor

Abstract

An integrated circuit is provided which includes a sensing circuit. In the sensing circuit, a pair of conductors including a first conductor and a second conductor are adapted to conduct a first differential signal having a small voltage difference and a second differential signal having a rail-to-rail voltage difference. A sense amplifier is coupled to the pair of conductors, the sense amplifier being operable to amplify the first differential signal into the second differential signal. The sensing circuit further includes a multiple conduction state field effect transistor or 'multi-state FET' which has a source, a drain, and a gate operable to control conduction between the source and the drain. The multi-state FET has a first threshold voltage and a second threshold voltage which is effective at the same time as the first threshold voltage such that the multi-state FET is operable by the gate voltage to switch between an essentially nonconductive state, a first conductive state when a gate-source voltage applied between a gate and a source of the FET is between the first threshold voltage and the second threshold voltage, and a second conductive state when the gate voltage exceeds the second threshold voltage. The multi-state FET is used to perform an operation included in amplifying the first signal into the second signal by the sense amplifier.