Chapter 2
Subthreshold Source-Coupled Logic
2.1 Introduction
Without any doubt, energy dissipation is one of the major concerns of our modern world. In integrated systems, regardless of operating conditions, this parameter plays a very critical rule in any kind of design. Generally, there is a tight tradeoff between performance of a system and its energy consumption and power efficiency. The power efficiency can be measured by amount of energy that needs to be dissipated to achieve a specific performance level:
Based on this definition of figure of merit (FOM), different designs can be categorized in different levels of energy efficiency such as energy-efficient, low energy (low power), and ultralow energy (ultralow power). Energy efficiency or equivalently FOM depends on many different parameters 43 and generally a very careful design approach is required to obtain an optimized result.
- Fabrication technology: Generally technology scaling provides faster transistors with less parasitic effects which helps to improve the energy efficiency of a system. Unfortunately, this sentence is not always correct. For example, by technology scaling different sources of leakage current aggregate the static power dissipation of a system which translates ...
