A comparator includes a second-stage circuit, a first input circuit, a second input circuit, a first cross-coupled circuit and a second cross-coupled circuit. The first input circuit is configured to generate a first data terminal voltage and a first reference terminal voltage. The first cross-coupled circuit is configured to perform mutual positive feedback on the first data terminal voltage and the first reference terminal voltage to generate a first differential signal. The second input circuit is configured to generate a second data terminal voltage and a second reference terminal voltage. The second cross-coupled circuit is configured to perform mutual positive feedback on the second data terminal voltage and the second reference terminal voltage to generate a second differential signal. The second-stage circuit is configured to amplify and latch the first differential signal or the second differential signal in a regeneration phase to output a comparison signal.