An amplifier device includes an amplifier circuit, a feedback circuit, and a filter circuit. The amplifier circuit is configured to receive an input signal and a filtered signal, and to output a firstoutput signal and a second output signal at a first output terminal and a second output terminal respectively. The first output signal and the second output signal are a pair of differential signals.The feedback circuit is configured to set direct current (DC) voltage levels of the first output signal and the second output signal to be at a predetermined voltage. The filter circuit is used for low-pass filter of the first input signal or low-pass filter of the pair of differential signals so as to generate the filtered signal, and is used for outputting the filtered signal to the amplifier circuit.