An ILP Formulation for Minimizing the Number of Feedthrough Cells in a Standard Cell Placement

Abstract

It is well known that standard cells have been widely used to implement VLSI circuits in the automation of physical design. Since one major aim of a cell-based design is to minimize total layout area in a standard cell placement, the number of feedthrough cells will be minimized to reduce total cell area in a standard cell placement. In this paper, first, we model a partitioning-based row assignment (PRA) problem to minimize the number of feedthrough cells in a standard cell placement. Furthermore, an integer linear programming (ILP) approach is proposed to solve the PRA problem in a standard cell placement. Finally, the ILP approach has been implemented and two standard-cell netlists, Primary 1 and Primary 2, have been tested by the proposed approach, Bose's approach [4] and an exhaustive search approach, respectively. The experimental results show that the ILP approach obtains fewer feedthrough cells than Bose's approach in a partitioning-based standard cell placement.