Interpolating sense amplifier circuits and methods of operating the same

Abstract

A circuit includes a first pre-amp circuit that provides a first pre-amp current and a second pre-amp circuit that provides a second pre-amp current. A first threshold circuit is configured to generate a first output signal responsive to a difference between a variable current and the first pre-amp current. A second threshold circuit is configured to generate a second output signal responsive to a difference between the variable current and the second pre-amp current. One of the branches of a differential interpolation circuit includes a first transistor that is connected in a current mirror configuration with the first pre-amp circuit. The first transistor has a width/length ratio equal to the product nk, where n<1. A second transistor is connected in a current mirror configuration with the second pre-amp circuit. The second transistor has a width/length ratio equal to the product mk, where m<1 and n+m is about 1. The interpolation circuit is configured to generate a third output signal responsive to a difference between the variable current and an interpolated reference current given by n*(first pre-amp current)+m*(second pre-amp current).