A Review on Sub-0.21-V Ultra-Low-Supply-Voltage Analog-to-Digital Converters

Ultra-low-supply-voltage (ULV) analog-to-digital converters (ADCs) operating at 0.21 V or lower are attractive for Internet-of-Things (IoT) and embedded applications due to their extremely low power consumption. This paper surveys state-of-the-art ULV ADCs to evaluate current trends and design strategies. Architectures, circuit implementations, and calibration techniques are analyzed and key trends are identified. Based on the observations, the paper provides recommendations for the circuit designer to make judicious design choices to obtain the desired performance for ULV ADCs. This paper further explores the VCO-based architecture and proposes a new topology to achieve high resolution for ULV ADCs.