Abstract: A technique to verify, evaluate, and estimate the performance of an integrated circuit is embodied in a computer software program that is executable by a computer system. The technique accurately estimates of the performance (e.g., transient delays) of an integrated circuit, and has fast execution times. The technique includes an incremental recharacterization feature where only portions of the design which have been changed or are new or different will need to be recharacterized during subsequent runs of the software. Portions of the design which are the same need not be recharacterized, and results for those portions from a previous run (stored in a database) are used. This saves execution time since the performance recharacterization or evaluation process is generally more time consuming than a database look up. The technique is applicable to small circuits having relatively few transistors, and especially well suited for integrated circuits having millions of transistors and components.

Abstract: What is disclosed is a method for budgeting timing in a hierarchically decomposed integrated circuit design, which includes: 1) optimizing at least one path through block pins, the optimization resulting in assigned gains for all the cells along said at least one path; 2) performing timing analysis on the at least one path, the timing analysis using the assigned gains in order to generate arrival times for signals at said block pins; and 3) deriving a tinting budget by examining said generated arrival times at said block pins.

Abstract: An automated method for designing an integrated circuit layout using a computer based upon an electronic circuit description and based upon cells which are selected from a cell library, each of the cells having an associated area, comprising the steps of: (a) placing each of the cells in the integrated circuit layout so that the cells can be coupled together by wires to form a circuit path having an associated predetermined delay constraint wherein the cells are coupled together based upon the electronic circuit description input to the computer; (b) connecting the cells together with the wires to form the circuit path; and (c) adjusting an area of at least one of the cells to satisfy the associated predetermined delay constraint of the circuit path.

Abstract: 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.

Abstract: 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.

Abstract: Disclosed is a subgrid detailed router that performs searches for wire locations at the grid level. Once a solution is found, the wire is placed in a based upon a finer subgrid. Specifically, the present invention includes subgrids that in a preferred embodiment have a resolution that is 16X greater than the resolution of the conventional grids. This increased resolution is useful for improving routing density with variable width and variable spacing designs. In operation, the subgrid detailed router of the present invention searches at the grid level for potential wire paths using a code associated with each grid. This code contains data corresponding to each of the subgrids, such that upon completion of a routing a net, information exists that allows for the placement of the net at locations corresponding to the subgrid that has finer resolution than the grid which was used to implement the routing search.

Abstract: An automated logic circuit design system uses a common database to store design data at different states of the design process, including data-flow graphs, netlists and layout descriptions. In this way, the need to translate circuit descriptions between tools is eliminated, thus leading to increased speed, flexibility and integration. The common database includes entities, models, cells, pins, busses and nets. The data-flow graphs are stored as graphs, the nodes in a graph as cells, and the edges as busses. Physical design data is available by storing the cells in a model in a KD tree. This allows queries on cells in the netlist located in the layout within arbitrary areas.

Abstract: 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.

Abstract: An automated logic circuit design system uses a common database to store design data at different states of the design process, including data-flow graphs, netlists and layout descriptions. In this way, the need to translate circuit descriptions between tools is eliminated, thus leading to increased speed, flexibility and integration. The common database includes entities, models, cells, pins, busses and nets. The data-flow graphs are stored as graphs, the nodes in a graph as cells, and the edges as busses. Physical design data is available by storing the cells in a model in a KD tree. This allows queries on cells in the netlist located in the layout within arbitrary areas.

Abstract: An automated method for designing an integrated circuit layout using a computer based upon an electronic circuit description and based upon cells which are selected from a cell library, each of the cells having an associated area, comprising the steps of: (a) placing each of the cells in the integrated circuit layout so that the cells can be coupled together by wires to form a circuit path having an associated predetermined delay constraint wherein the cells are coupled together based upon the electronic circuit description input to the computer; (b) connecting the cells together with the wires to form the circuit path; and (c) adjusting an area of at least one of the cells to satisfy the associated predetermined delay constraint of the circuit path.

Abstract: An automated method for designing an integrated circuit layout using a computer based upon an electronic circuit description and based upon cells which are selected from a cell library, each of the cells having an associated area, comprising the steps of: (a) placing each of the cells in the integrated circuit layout so that the cells can be coupled together by wires to form a circuit path having an associated predetermined delay constraint wherein the cells are coupled together based upon the electronic circuit description input to the computer; (b) connecting the cells together with the wires to form the circuit path; and (c) adjusting an area of at least one of the cells to satisfy the associated predetermined delay constraint of the circuit path.

Abstract: 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.

Abstract: An automated method for designing an integrated circuit layout with a computer, based upon an electronic circuit description and upon a selected plurality of cells from a cell library, comprising the steps of: (a) assigning each of the cells to one of a plurality of buckets designated on the integrated circuit layout, each of the cells being connected to one of the other cells; (b) performing global routing to connect at least some of the selected cells of step (a) together such that global routes are formed to provide net topology information; (c) performing track routing which sets the position of each of the global routes; (d) performing detailed placement such that the positions of all selected cells are fixed within each of the buckets designated on the integrated circuit layout; and (e) performing detailed routing such that detailed routes are formed to complete the integrated circuit layout.