MOS-only biquads with extended operating frequency range

In this paper, a MOS-only multifunction filter which simultaneously realizes second-order lowpass and bandpass functions is presented. It is shown that the filter offers very useful advantages, such as low occupied chip area and suitability for high-frequency operation. Although the operation frequency range of the filter is found to be limited, a circuit design technique is proposed to remedy this issue. The validity of the theoretical discussions is verified by Spectre simulation results.