Near-Threshold Operation: Technology, Building Blocks and Architecture

This chapter explores the key aspects of near-threshold operation. Technology constraints, building blocks and architectural aspects for operating circuits at ultra-low voltage are discussed. All the simulations and prototypes developed in Chap. 2–6 were acquired using a 40-nm CMOS technology. The transistor behaviour of said technology is the base of all the design considerations made further on. Section 2.1 lays out the ground work for this: transistor operating regions, device sizing, FO4 inverter performance and others are presented. These analyses enable an intuitive but surprisingly accurate insight in the microcontroller prototypes developed further in this work.