Signal-to-Noise Ratio, Dynamic Range, and Power Dissipation: Paying Attention to Their Interrelation Can Greatly Benefit Analog Circuit Design

Low power dissipation is paramount in an increasing number of applications. These notably include the Internet of Things and wireless sensor networks, in which a battery must last a very long time (even ten years in some cases) or in which energy harvesting is used. Battery life is also a key consideration in more traditional applications such as hearing aids and communication devices. All of these applications involve analog signals and require careful micropower circuit design. Such design can be more efficient if guided by an understanding of the fundamental limits [1]-[4], beyond which nature does not allow us to go. In this article, we review the relation between power dissipation and signal-to-noise ratio (SNR) for analog circuits. We make a crucial distinction between SNR and usable dynamic range (UDR) and review ways to allow the SNR to vary as needed, thus extending the UDR and resulting in adaptive power dissipation.