Abstract: A comparator circuit has a pre-charging and early reset output stage. The comparator circuit includes: a first pre-charging transistor and a second pre-charging transistor. A gate of the first pre-charging transistor is connected to a pre-charging signal, and a gate of the second pre-charging transistor is connected to a main clock signal, wherein the pre-charging signal is enabled earlier than the main clock signal. At a pre-charging phase, there is a small electric current, and a comparator slowly amplifies an input small signal to reduce noise; and the electric current is increased after a certain time delay, such that on the basis of pre-charging, the comparator rapidly completes a pre-amplification phase and then enters a regeneration phase.

Abstract: The present invention discloses a circuit for improving linearity and channel compensation of PAM4 receiver analog front end, comprising a first stage and a second stage, the first stage comprising first to twentieth transistors, a first resistor, a pair of second resistors, a pair of first capacitors, and a pair of second capacitors. In the first stage circuit, the ninth and tenth transistors are directly coupled to the ground, eliminating the electrical connection to the bias current source. The Input terminals of the ninth and tenth transistors are coupled to the output signals of the preceding nineteenth and twentieth transistors, so that the ninth and tenth transistors serve as both input pairs and current source transistors. The overall current is limited by the thirteenth and fourteenth transistors, which results in a lower power supply voltage for the first stage consisting of the ninth through fourteenth transistors.