Active CMOS Inductors for RF and High-Frequency Circuits: A Comprehensive Analysis

Active CMOS inductors have emerged as essential components in modern integrated circuits (ICs), offering significant advantages over passive inductors in terms of size, performance, and power efficiency. This paper provides a comprehensive overview of the design methodologies, key design metrics, and applications of active CMOS inductors. This paper begins with introducing fundamental concepts of inductors in CMOS technology, highlighting the limitations of passive inductors and the evolution of active inductors. After that, it discusses the benefits and limitations of several design approaches, including bootstrapped, negative resistance-based, LC resonator-based and gyrator C-based active inductors. Furthermore, it examines the key design considerations crucial for achieving desired performance metrics such as equivalent inductance, quality factor (Q-factor), self-resonant frequency, power consumption, noise performance, tunability, linearity, and bandwidth. It also outlines future research directions and emerging trends in active CMOS inductor design, paving the way for continued innovation and advancement in this field.