The Digital-Based Operational Transconductance Amplifier: Evolution and Perspective

The evolution of the Digital-Based Operational Transconductance Amplifier (DB-OTA), which was initially introduced to address the challenges related to the implementation of analog functions in aggressively scaled technology nodes is reviewed in this paper, starting from the first proof-of-concept prototype up to the most recent ultra-compact area, ultra-low voltage and ultra-low power solutions. The improvement in performance and the potential of this approach in meeting the requirements of Internet of Things (IoT) sensor nodes and next-generation biosensing will be discussed.