A.3 Digital Systems

Larger combinations of digital circuits with a certain architecture are called digital systems, e.g., microprocessors, large memories, or whole computers. Real-world digital systems can be fairly complex so that the modeling of such systems is a discipline of its own. A pioneering work in this field is SUSPENS CPU model [5] on which many other models are based (e.g., [22,41,74]). For this work a simple model of a homogeneous system described in the following is sufficient to demonstrate the concepts of Ultra-Low-Power CMOS.