Magma Design Automation, Inc.

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Hamid Savoj

Lukas P P P Van Ginneken

Manjit Borah

Emre Tuncer

Prasanna V Srinivas

Raymond X T Nijssen

A process for reducing cross-talk noise in a VLSI circuit is disclosed. The process identifies a victim net in an integrated circuit and calculates a change in ground capacitance for the victim net to identify a noise amplitude less than or equal to a maximum allowable noise height. The process selects from a library one cell or a grouping of cells having an input capacitance for the victim net closest to the change in ground capacitance. The selected cell or grouping of cells is coupled to the victim net so that its change in ground capacitance provides a noise amplitude less than (or less than or equal to) an allowable maximum noise height that may be a predetermined value. A system for reducing cross-talk noise in a VLSI circuit is also disclosed.

Reduction of cross-talk noise in VLSI circuits

A fast method of estimating capacitances and wire delays in an integrated circuit design is based on placement information such as that contained in a gate schematic net list from a logic synthesis tool. A simple tree topology called a spine tree is constructed to connect the pins of the net as an approximation of actual connections therein. Capacitance is extracted for this topology assuming a worst case scenario, and Elmore delays are computed for the wire delays based on the worst-case capacitances. The method takes linear time as a function of the number of pins in the net and is much faster than using a Steiner tree method in this context.

Method for rapid estimation of wire delays and capacitances based on placement of cells

A strategy for optimal buffering in the case of an infinitely long wire buffered with an arbitrary number of equally spaced single-size buffers is presented. A simple but efficient technique is proposed using this to choose a buffer size and determine a good inter-buffering distance up front, thus enabling fast, efficient buffer insertion. The analysis also allows representing delays of long wires as a simple function of the length and buffer and wire widths. Based on this, a novel constant wire delay approach is proposed where the proposed wire delay model is used for fairly accurate prediction of wire delays early in the design process and these predictions are later met via buffer insertion and wire sizing.

Timing optimization in presence of interconnect delays

A system for calculating interconnect wire lateral capacitances in an automated integrated circuit design system subdivides the chip area of a circuit design to be placed and routed into a coarse grid of buckets. An estimate of congestion in each bucket is computed from an estimated amount of routing space available in the bucket and estimated consumption of routing resources by a global router. This congestion score is then used to determine the spacing of the wires in the bucket which is in turn used to estimate the capacitance of the wire segment in the bucket.

System and method for estimating capacitance of wires based on congestion information

Methods and apparatuses for automated design of parallel drive standard cells are disclosed. The capacitive load to be driven by a particular output of a standard cell is determined. The driving capacity of the output is also determined. Based on the capacitive load to be driven and the driving capacity, a number of standard cells to be used is determined. The multiple standard cells are coupled in parallel having the respective outputs coupled to the capacitive load to be driven. In one embodiment, the standard cells coupled is parallel are placed such that the connection between the respective outputs and the load are substantially equal.

Automated design of parallel drive standard cells

A method for designing a sequence of logic gates in a path is described. In one embodiment, the method includes modeling gate delay as a function of input slew and output load using a delay model and adjusting electrical efforts in each stage to reduce the gate delay along the path. In one embodiment, the electrical efforts in each stage are adjusted to minimize the delay along the path, where the delay along the path is minimized when a product of logical effort and electrical effort associated with each gate is the same.

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Daly City, CA, United States of America

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