A single-stage buffer apparatus includes a first transistor, a second transistor, and a high pass filter network. The first transistor is configured to receive an input signal from a microphone. The second transistor is configured to operate as a cascode transistor. The high pass filter network is coupled to the first transistor and the second transistor. The second transistor electrically decouples the first transistor from an output of the single-stage buffer apparatus. A gate terminal of the second transistor is driven by the high-pass filter network, and the high-pass filter network is driven by the first transistor.