Design of a New Low-Voltage Low-Power Operational Transconductance Amplifier for OTA-C Filter Applications

This study proposes a novel fully differential operational transconductance amplifier (FD-OTA) based on fully differential inverters. To reduce power consumption and improve performance at low voltages, the proposed amplifier uses two techniques; i.e., bias in the subthreshold region and body-driven technique. The circuit simulations are performed using the HSPICE software in 180 nm CMOS fabrication. The proposed amplifier consumes only 0.4 µW at supply voltages of ±0.3 V. Moreover, this amplifier has a single output gain of 73 dB and a differential output gain of 79 dB. The output swing of this amplifier is 0.4 Vp-p and the unity-gain frequency of the circuit is about 3.6 MHz for a 1pF load capacitance. The input-noise is equal to 211 nV/√Hz at a frequency of 1 kHz and the slew rate (SR) is equal to 550 V/µs. The proposed OTA circuit is suitable for biomedical applications with high gain, low voltage, low input-referred noise, real-time response, and 1 kHz frequency bandwidth.