No abstract

We devise a central triangular sequence to minimize the escape routing layers in area array packaging. We use a network flow model to analyze the bottleneck of the routable pins. The triangular patterns are generated in a reverse order from the last to the first layer. We demonstrate that the triangular pin sequence maximizes the sum of escape pins in the accumulated layers and thus minimize the number of escape routing layers. A test case is presented to illustrate the approach.

Power consumption of system-level on-chip communications is becoming more significant in the overall system-on-chip (SoC) power as technology scales down. In this paper, we propose a low power design technique of gated bus which can greatly reduce power consumption on state-of-the-art bus architectures. By adding demultiplxers and adopting a novel shortest-path Steiner graph, we achieve a flexible tradeoff between large power reduction versus small wirelength increment. According to our experiments, using the gated bus we can reduce on average 93.2% of wire capacitance per transaction, nearly half of bus dynamic power and on a scale of 5%∼10% of total system power.

3-D VLSI circuit is becoming a hot topic because of its potential of enhancing performance, while it is also facing challenges such as the increased complexity on floorplanning and placement. Efficient 3-D floorplan representations are needed to handle the placement optimization in new circuit designs. We review and categorize some state-of-the-art 3-D representations, and propose a twin quaternary tree (TQT) model for 3-D mosaic floorplans, extending the twin binary tree [16]. Differences between 2-D and 3-D mosaic floorplans are discussed and some 3-D properties not existing in 2-D are revealed. Though the efficiency of the twin tree for optimization heuristics is still an open question, insights from the discussions and conclusions can be helpful for 3-D physical design.

3-D packing is an NP-hard problem with wide applications in microelectronic circuit design such as 3-D packaging, 3-D VLSI placement and dynamically reconfigurable FGPA design. We present a complete representation for general non-slicing 3-D floorplan or packing structures, which uses a labeled tree and dual sequences. For each compact placement, there is a corresponding encoding. The number of possible tree-sequence combinations is (n + 1) n−1 (n!) 2 , the lowest among complete 3-D representations up to date. The construction of placement from an encoding needs O(n 2 ) in the worst case, but in practical cases we expect O(n 4/3 log n) time on average for circuit blocks with limited length/width ratios. Experimental results show promising performance using the labeled tree and dual sequences on 3-D floorplan and placement optimizations.