Cascaded third-order tunable low-pass filter using low voltage low power OTA

A low voltage low power tunable Operational Trans-conductance Amplifier (OTA) is presented in this paper. The OTA is tuned via a control voltage. The OTA power consumption is 0.15mW at 1V supply voltage. A digitally controlled Master/Slave tuning scheme is applied to generate the OTA control voltage. The trans-conductance gain of the OTA is varied from 9.3μA/V to 35.29μA/V. The proposed OTA is used to realize a cascaded third-order low-pass filter. The filter cutoff frequency is tuned from 4.75MHz to 12.79MHz. The circuit is realized using 90nm CMOS technology model from MOSIS under 1V single ended supply. Simulations using ADS are presented.