Design of 1 V Operating Fully Differential OTA Using NMOS Inverters in 0.18 µm CMOS Technology

Abstract: A 1 V operating fully differential OTA is presented. We designed a 1 V operating fully differential OTA using NMOS inverters in place of traditional differential pair. To obtain high voltage gain, a two stage configuration has been used in which the first stage has feedforward to cancel common-mode signal and the second stage has commonmode feedback. This OTA was fabricated by 0.18 μm CMOS technology. Measured dc gain is 40 dB and a unity gain frequency is 10 MHz. This OTA leads a solution to the low supply voltage issue in scaled CMOS analog circuits.