A novel design of two-stage CMOS amplifier used for εΔ analog to digital converter

Abstract

Operational transconductance amplifier (OTA) is one of the most significant building-blocks in integrated discret-time filters used in analog to digital converter (ADC) for Sigma-delta converter. In this paper we designed a novel structure of two-stage CMOS amplifier in AMS 0.35μm technology. Simulation results confirm the proposed OTA circuit. In fact, we achieved a gain band width (GBW) equal to 80MHz, Cut-off frequency (fb) of 95 KHz and 60 dB gain (Av). In addition our new circuit allowed us to reduce settling time (St) to 30 ns and a slew rate (SR) of 50 ν/μs at ±1.5V supply voltage. Eventually we have also succeeded in reducing the static power consumption to 0.36 mW.