Design and Demonstration of MEM Relay-Based Arithmetic and Sequential Circuit Blocks

The Internet of Things (IoT) has become more prevalent in recent years and is an integral part of everyday life. Thus, the need for ultralow-power sensors and processing units has dramatically increased. The continuous scaling of CMOS transistors has resulted in more severe subthreshold leakage and high power density issues. In recent years, microelectromechanical (MEM) relays have attracted research interests. They are viewed as promising beyond-CMOS candidates due to their nonleaking property and abrupt switch ON/OFF characteristics. This article presents the design and characterization of a few core relay-based digital blocks, including an adder and a D-latch. While the mechanical movement of relays makes them inherently slower than transistors, we show that the scaled 32-bit relay adder offers 60 times less energy per operation than its CMOS counterpart in 40-nm technology. This makes the proposed relay circuits particularly appealing to applications with stringent demand on energy efficiency and moderate performance requirements, such as remote sensors, wearable accessories, and implantable biomedical devices.