AKORD: transistor level and mixed transistor/gate level placement tool for digital data paths

Abstract

Describes AKORD, a transistor-level and mixed transistor/gate-level placement tool. AKORD has unique layout capabilities that address the digital data path layout problem. In order to improve communication between the placement and routing steps, new post-placement algorithms were developed: a device re-spacing procedure, an optimization procedure for gate contacts, and a procedure which reduces wire crossovers. AKORD dynamically supports: (1) transistor folding without the usage of device libraries that contain variants of the same device; (2) device merging, including information about optimal transistor chain formation; and (3) well area minimization. Experimental results show that the automated layouts are comparable to skilled manual layouts and that the computation times are quite modest.