Low Power Low Pass Operational Transconductance Amplifier based RC Active Filter

In this paper, Clocked Transconductor topology is employed in the design of an OTA-based Low Pass RC Active Filter. The filter is designed and validated in Cadence virtuoso using 0.18 µm GPDK at the supply voltage of 1 V. The filter employs two differential amplifiers, two current mirrors and one common-source MOSFET, one resistor, and one capacitor with a single-ended input supply. This Filter provides a Low Pass response with a transconductance of 791.47 pS, a cut-off frequency of 68.223 Hz, low input noise of 11.38 µV/√Hz, low output noise of 53.09 µV/√Hz, very low power consumption of 189.527 pW with low THD of 0.344%. The attractive feature of the filter includes (i) a Cut-off frequency below 70 Hz, (ii) the Ability to operate with a single input supply, (iii) the ability to amplify the input signal by 3.5 times, and (iii) Low power consumption in pW range. With an area of 189.9 µm
²
having dimensions of 13.885 µm × 13.680 µm, 4% variation in cut-off frequency and an 8% variation in power consumption are seen as compared to pre-layout simulation results which validate the proposed designs. A comparative study of the state-of-the-art OTA filter designs with the proposed filter is also provided which shows that this filter circuit outperforms all other similar types of filters in terms of cut-off frequency, power consumption, noise, and supply voltage and could be utilized in the realization of a portable biomedical analog front-end interface