Operational Transconductance Amplifier-Based Low-Pass Filters in Biomedical Signal Processing: A Review of Design Considerations and Performance

The world of biomedical electronics is changing rapidly with the addition of newer circuit components and newer fabrication technologies day by day. The portability of biomedical devices is challenging due to size and battery life concerns and smaller geometries the poor noise performance and lack of linearity in performance are another big challenge. Operational transconductance amplifiers (OTAs) have recently gained much popularity in biomedical applications due to their requirement of low power and low voltage for operation yet offering low noise and good linearity at output. OTAs have also found wide application in data converters, sensors and signal processors including analog processing blocks as well. This study examines the behavior of previously reported CMOS OTAs in various literature works, based on their operational characteristics. Different OTA configurations are compared on the basis of their linearity, design technology, supply voltage, power consumption, cut-off frequency and bandwidth specifically for biomedical signal processing. This paper is a useful resource for researchers who wish to design OTA-based different circuits for biomedical applications and need a summary of performance characteristics of different types of OTAs reported so far.