Internet-of-things (IoT) systems combine sensing, computation, storage, and communication to sense physical systems and respond accordingly. However, larger size chips are not suitable for fog and edge devices. Therefore, a new mindset is required for VLSI design to implement the IoT application. This chapter describes the first conventional technology used in VLSI design. Afterward, the characteristics of IoT systems relevant to VLSI design identify essential factors and challenges at different levels. Finally, the fifth-generation network (5G) is also studied to expand IoT applications.