A new ultra low-power, universal OTA-C filter in subthreshold region using bulk-drive technique

In this paper, a new ultra low-power universal OTA-C filter which can properly operate in all modes of operation (voltage, current, trans-resistance and trans-conductance) is presented. However, in order to reduce the power consumption effectively, the proposed circuit uses subthreshold transistors which are biased at I-a = 50 nA, I-b = 150 nA. Furthermore, using the bulk-drive technique leads to a reduced power consumption as well as the supply voltage of +/- 0.3 V. Moreover, the grounded capacitors are used to effectively reduce the parasitic effects. However, the result of sensitivity analysis shows that the proposed circuit has a very low sensitivity to the values of active and passive circuit elements such as: trans-conductance (g(m)) and capacitance (C) values. Furthermore, the proposed circuit uses the minimum number of active elements to effectively reduce the power consumption as well as the chip area. Finally, the proposed filter is designed and simulated in HSPICE using 0.18 mu m CMOS technology parameters, while HSPICE simulation results have very close agreement with theoretical results obtained from MATLAB, which justifies the design accuracy and low-power performance of the proposed universal filter.