An amplifier includes a differential input stage, a hysteresis stage, coupled to the differential input stage, a cascode stage coupled to the hysteresis stage, a feedback stage coupled to an output of the cascode stage and configured to provide a feedback signal to the hysteresis stage, and an output stage coupled to the output of the cascode stage. The output stage includes a hysteresis inverter coupled between the output of the cascode stage and the amplifier output.

An amplifier includes a differential input stage, a hysteresis stage, coupled to the differential input stage, a cascode stage coupled to the hysteresis stage, a feedback stage coupled to an output of the cascode stage and configured to provide a feedback signal to the hysteresis stage, and an output stage coupled to the output of the cascode stage. The output stage includes a hysteresis inverter coupled between the output of the cascode stage and the amplifier output.

An amplifier includes a transconductance amplification module, a feedforward transconductance module, and a gain control module. An input control terminal pair of the transconductance amplification module is connected to an input signal pair, and the transconductance amplification module is configured to convert the input signal pair into an output current pair and output the output current pair. A first feedforward control terminal pair included in the feedforward transconductance module is connected to the input signal pair and outputs a feedforward current pair. The gain control module includes a first differential pair and a second differential pair. The first differential pair is configured to perform compensations for a positive-phase output current and a negative-phase output current of the output current pair respectively. The second differential pair is configured to perform compensations for the positive-phase output current and the negative-phase output current in the output current pair respectively.