A Novel 0.4-V Current-Biased Inverter-Based Two-Stage Fully-Synthesizable OTA

This paper presents a novel 0.4-V current-biased inverter-based two-stage fully-synthesizable operational transconductance amplifier (OTA), targeting ultra-low-power analog signal processing in standard-cell design environments. For the first time, a synthesizable current-biasing technique compatible with digital design flows is introduced and integrated into a two-stage inverter-based OTA topology. The proposed architecture eliminates the need for custom bias circuitry, enabling fully-automated implementation and scalability across CMOS technology nodes. Operating at 0.4-V supply and implemented in standard 180-nm CMOS technology, the OTA achieves competitive gain and bandwidth metrics while maintaining nanowatt power consumption, making it well suited for energy-constrained applications such as IoT edge nodes and biomedical interfaces. Simulation results validate the effectiveness of the proposed design, demonstrating its capability to bridge the gap between analog functionality and digital synthesizability.