ABSTRACT
This chapter describes the common constraints in very large-scale integrated (VLSI) design, and how they are enforced through the steps of a design flow. It looks at the overall design closure process, which takes a chip from its initial design state to the final form in which all of its design constraints are met. The chapter introduces a reference design flow. It discusses the nature and evolution of design constraints. The chapter explains about the specific design constraints that are facing chip designers. It presents a detailed walk-through of a typical design closure flow. In the early days of VLSI, a chip consisted of a few thousand logic circuits which performed a simple function at speeds of a few MHz. Design closure at this point was simple: if all of the necessary circuits and wires “fit,” the chip would perform the desired function.
