Revisiting Routability-Driven Placement for Analog and Mixed-Signal Circuits

Abstract

The exponential increase in scale and complexity of very large-scale integrated circuits (VLSIs) poses a great challenge to current electronic design automation (EDA) techniques. As an essential step in the whole EDA layout synthesis, placement is attracting more and more attention, especially for analog and mixed-signal integrated circuits. Recently, experts in this field have observed a variety of analog-specific layout constraints to obtain high-performance placement solutions. These constraints include symmetry, alignment, boundary, preplace, abutment, range and maximum separation, and routability of the placement solutions. In this article, the effectiveness of slicing and nonslicing representation is investigated. Additionally, the technique of congestion-based virtual sizing is proposed. Experimental results show that the routability can be improved significantly by applying congestion-based virtual sizing. Results also show that the slicing representation can improve the regularity of the placement solutions and hence improve the routability with higher efficiency compared to the nonslicing representation.