Simultaneous Transistor Pairing and Placement for CMOS Standard Cells

Ang Lu, Hsueh-Ju Lu, En-Jang Jang, Yu-Po Lin, Chun-Hsiang Hung, Chun-Chih Chuang and Rung-Bin Lin

Computer Science and Engineering, Yuan Ze University, Chung-Li, Taiwan

ABSTRACT

This paper presents an integer linear programming approach to transistor placement problem for CMOS standard cells with objectives of minimizing cell width, wiring density, wiring length, diffusion contour roughness, and misalignments of common ploy gates. Our approach considers transistor pairing and transistor placement simultaneously. It can achieve a smaller number of transistor chains than the wellknown bipartite approach. About 31% of the 185 cells created by it have smaller widths and no cells whose widths are larger than their handcrafted counterparts.

Keywords: Transistor placement, Transistor pairing, Transistor folding, Standard cell.

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