Design of CMOS Operational Transresistance Amplifier with Improved Gain and Bandwidth

Abstract

Longer shelf life, fast operating speed are necessities for portable electronics systems. Ever shrinking feature size of devices on ICs and consequential reduction of power supply voltage can be handled by operating in the current domain, as the current-mode circuits are low impedance node networks, and thus low time constant circuits, too. This improves system performance in terms of speed and slew rate. OTRA uses current mode designing techniques. In OTRA shunt-shunt feedback is used which makes amplifier and feedback network parallel and parallel networks support low power supply. Because of use of current-feedback technique, OTRA has bandwidth independent of closed loop voltage gain In this thesis, a novel OTRA has been designed with improved gain and bandwidth. The proposed circuit provides gain of 165.76db and 3db bandwidth of 663.24Khz. The vital parameters of proposed circuit have also been compared with existing OTRA circuits. The proposed circuit is simulated using cadence in 180 nm CMOS technology parameters with supply voltages of ±.9 V. Corner analysis also has been performed. The comparison of proposed OTRA with OTRAs available in literature survey shows that there is considerable increase in gain and bandwidth.