A 0.6 V, 2nd order low-pass Gm-C filter using CMOS inverter-based tunable OTA with 1.114 GHz cut-off frequency in 90nm CMOS technology

A low-pass active filter (Gm-C) with 1.114 GHz cut-off frequency at 0.6 V supply voltage is presented wherein the basic element of this filter is a CMOS inverter. A low-voltage high-frequency operational transconductance amplifier (OTA) is designed and simulated using CMOS inverters. The common mode feedforward and common mode feedback circuits were incorporated with tuning circuits to tune the DC gain and bandwidth and consequently, enhance the linearity. The circuit is designed and simulated in 90nm CMOS technology. The differential DC gain, bandwidth (-3 dB cut-off frequency) and the unity gain frequency of the OTA are 14 dB, 381 MHz and 3.48 GHz, respectively. The filter consumes 1.55mW to achieve a figure-of-merit of 1.5 GHz/mW. It is a promising candidate for low-power broadband communication applications.