Process-Scalable and Low-Power Amplifiers: Progress and prospects in dynamic amplifier research

Amplifiers are critical components in many applications. They simply perform signal amplification, but real-world implementation must consider several challenges, such as finite BW, signal distortion, noise, stability, and so on. Solutions to these problems typically involve circuit techniques that lead to high power consumption. Therefore, numerous studies have been conducted to break the tradeoff between performance and power. Among the most promising candidates is the current-reuse structure [1], [2], [3], [4], [5], [6]. Such amplifiers have continuously improved their power efficiency factor (PEF) performance year by year. However, there are essential limitations to consider. First, the supply voltage significantly decreases as the process node advances. This process scaling not only makes it challenging for amplifiers to achieve high gain but also significantly degrades linearity. Second, conventional amplifiers, meaning continuous-time (CT) amplifiers, operate with a static current. While better PEFs of CT amplifiers improve overall performance envelopes in many CT-domain applications, they exhibit clear limitations in discrete-time (DT)-domain or mixed-signal applications.