Design of a Three Stage Operational Transconductance Amplifier in 90nm CMOS

In this paper, a simple design for bulk-driven operational transconductance amplifier (OTA) is proposed. The design comprises of a three stage OTA with additional current mirrors working as an active load. The OTA is designed in standard 1P-9M UMC 90nm CMOS technology. The proposed OTA operates at a low supply voltage of 0.7V and consumes $48 \mu\mathrm{W}$. The unity gain frequency 3.65 MHz and DC gain of 54 dB is achieved at a 20pF capacitive load. The Figure of Merits (FOM), used in this article to measure the design performance, indicate that the proposed architecture gives better small signal and large signal performances, when compared with other designs.