A CMOS OTA and Implementation

This paper proposes a low voltage wide input linear range CMOS Operational Transconductance Amplifier (OTA). The voltage-to-current is carried by bulk-driven flipped-voltage follower differential pair input stage based on resistive source degeneration topology. The DC quiescent current of proposed OTA is determined by active load (diode-connected transistors) to provide a class-AB bulk-driven flipped-voltage follower differential pair input stage. The proposed design is optimized for a 0.8-V single power supply voltage. Simulation results of current tuning for the fully differential transconductance amplifier show wide linear differential input voltage range of 750-mV has one percentage of total harmonic distortion. The proposed OTA is implemented a CMOS biquad filter. Post layout simulation illustrates AC frequency responses for low-pass, band-pass, high-pass, and reject-band-pass filter through Specter simulator on 0.18-mu m CMOS technology.