A new design of OTA for Sigma-Delta ADC

Sigma-Delta Analog-to-Digital converter (ADC), is widely used in portable electronic products. An operational transconductance amplifier (OTA) is one of the most important components of this ADC. This paper reports a new design of low power fully differential OTA. In this design authors have used adaptive biasing technique and DC gain enhancement technique for improving design parameters as compared to earlier reported work. The design is simulated in 0.18μm UMC CMOS technology with supply voltage 1.2V. Simulation results are obtained with load capacitor and achieved improvement in results which are: DC gain 44.7dB, GBW 44.167MHz, the average power consumption is about 19μW and slew rate of 7.698V/μsec.