Analysis and Design of OTA topologies for Bio-Potential signals

Abstract

Biomedical signals are very small amplitude and low frequency signals. Hence they require high gain, high CMRR and low noise amplifiers for processing.  This paper presents Telescopic, Two stage and Folded cascode operational transconductance amplifier (OTA) topologies. The proposed OTA topologies employ a biasing, using constant current source with current mirror. The design of OTA is targeted for an implementation in biomedical devices. The proposed OTAs were designed in 180nm CMOS technology. Based on the simulation results, Telescopic OTA has high DC gain, wider bandwidth, lowest power dissipation and better settling time. Folded cascode OTA has moderate DC gain, wide bandwidth, lower power dissipation, higher CMRR and slew rate .Two stage OTA has moderate DC gain, low bandwidth with high power dissipation.