Extremely Low-Power Fifth-Order Low-Pass Butterworth Filter

A fifth-order Butterworth low-pass filter using multiple-input operational transconductance amplifiers (OTAs) is proposed in this paper. It is expressed that the number of OTAs that used for realizing fifth-order low-pass filter can be reduced using multiple-input OTA and results to decrease the power consumption and the active area. N-input OTA can be obtained using multiple-input bulk-driven quasi-floating gate technique. Subthreshold technique is used to achieve extremely low power consumption which can be applied to biomedical systems. The proposed topology is simulated using 0.18 μm standard CMOS process. Simulation results show that the proposed filter has a bandwidth located within 250 Hz, a power consumption of 41 nW and a dynamic range of 61 dB.