1. Introduction

The continuous downscaling of semiconductor technology, predicted by Gordon Moore in 1965, has had a major impact on the development of integrated electronics. The reduction of transistor size has allowed the integration of more and more devices in the same die, increasing the integration density. In addition, it has led to the reduction of fabrication costs, making the final product cheaper and more accessible. However, this increase in the functionality of an integrated circuit entails greater complexity in the generation and distribution of the different supply voltages required in a chip. As more systems are integrated into the same die, more biasing domains coexist requiring different noise, regulation and/or stability specifications to be simultaneously satisfied. Therefore, power management circuits have been acquiring greater significance as technology downscales, reaching a maximum at present, in the nanoscale era. Voltage regulators are key components for power management, as they provide a regulated, stable and noise-free supply voltage to the active blocks of an SoC. This chapter reviews the basics of voltage regulation with emphasis on linear regulators.