Abstract: Method and system are disclosed for statistical circuit simulation. In one embodiment, a computer implemented method for statistical circuit simulation includes providing descriptions of a circuit for simulation, wherein the descriptions include variations of statistical parameters of the circuit, partitioning the circuit into groups of netlists according to variations of statistical parameters of the circuit, simulating the groups of netlists using a plurality of processors in parallel to generate a plurality of output data files, and storing the plurality of output data files in a memory. The method of partitioning the circuit into groups of netlists includes forming the groups of netlists to be simulated in a single instruction multiple data environment, and forming the groups of netlists according to proximity of variations of statistical parameters of the circuit.

Abstract: Methods and systems are disclosed for naming methodologies for a hierarchical system. In one embodiment, a computer implemented method of organizing instance names in a hierarchical system includes receiving a description of a hierarchical system that includes plurality of instances arranged in different branches in a plurality of hierarchical levels in a physical data structure, creating an instance name data structure configured to describe the corresponding instances in the hierarchical system, where the instance name data structure comprises a map of indexes and a corresponding array of offsets configured to access naming information in a subsequent level, and associating names of instances in the hierarchical system to a corresponding set of unique integers which are arranged in a sequential manner.

Abstract: Methods and systems are disclosed for naming methodologies for a hierarchical system. In one embodiment, a computer implemented method of organizing instance names in a hierarchical system includes receiving a description of a hierarchical system that includes plurality of instances arranged in different branches in a plurality of hierarchical levels in a physical data structure, creating an instance name data structure configured to describe the corresponding instances in the hierarchical system, where the instance name data structure comprises a map of indexes and a corresponding array of offsets configured to access naming information in a subsequent level, and associating names of instances in the hierarchical system to a corresponding set of unique integers which are arranged in a sequential manner.

Abstract: Method and system are disclosed for simulating a circuit. The method includes representing a circuit using a matrix that represents a set of linear equations to be solved, identifying a delta matrix, which is a subset of the matrix that changed states from a previous time step to a current time step, computing an update of the delta matrix using a matrix decomposition approach, generating a current state of the matrix using a previous state of the matrix and the update of the delta matrix, and storing the current state of the matrix in a memory device.

Abstract: The present invention is directed to a number of improvements in methods for reliability simulations in aged circuits whose operation has been degraded through hot-carrier or other effects. A plurality of different circuit stress times can be simulated within a single run. Different aging criteria may be used for different circuit blocks, circuit block types, devices, device models and device types. The user may specify the degradation of selected circuit blocks, circuit block types, devices, device models and device types independently of the simulation. Device degradation can be characterized in tables. Continuous degradation levels can be quantized. Techniques are also described for representing the aged device in the netlist as the fresh device augmented with a plurality of independent current sources connected between its terminals to mimic the effects of aging in the device. The use of device model cards with age parameters is also described.

Abstract: The present invention includes a method for detecting model stamping errors during circuit simulation without the need for golden data. The method checks for model stamping errors by determining whether entries in model stamping matrices interrelate according to a plurality of preset rules before circuit equations are solved.

Abstract: System and method for validating a circuit for simulation are disclosed. The system includes at least one processing unit for executing computer programs, a graphical user interface for viewing representations of the circuit on a display, a memory for storing information of the circuit, and logic for representing the circuit in a hierarchical data structure, where the hierarchical data structure has a plurality of subcircuits arranged in a connected graph, and where each subcircuit has circuit elements and one or more input and output ports. The system further includes logic for traversing the hierarchical data structure in a bottom-up fashion, logic for recording input port to output port (port-to-port) properties of the subcircuits in the hierarchical data structure, logic for traversing the hierarchical data structure in a top-down fashion, and logic for identifying illegal port paths using the port-to-port properties of the subcircuits.

Abstract: Method and system for determining electrical isomorphism between two electrical networks are disclosed. In one embodiment, the method includes representing the circuit as a hierarchically-arranged set of branches, which includes a root branch and a plurality of other branches logically organized in a graph. The hierarchically-arranged set of branches including a first branch that includes a first electrical network and a second branch that includes a second electrical network, where the first and second branches are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches. Next, the method determines whether the first and second electrical networks are electrically isomorphic networks. If the first and second electrical networks are determined to be electrically isomorphic networks, the first and second electrical networks are represented with a single electrically isomorphic network.

Abstract: System and method for converting a flat netlist into a hierarchical netlist are disclosed. The method includes receiving the flat netlist, traversing the flat netlist in a bottom-up fashion, and identifying isomorphic subcircuits in the flat netlist. The method further includes creating a set of cross-coupling capacitor collections for storing information of cross-coupling capacitors, creating a set of net collections for storing information of isomorphic subcircuits, traversing each hierarchical level of the hierarchical netlist in a top-down fashion, and generating the hierarchical netlist using the set of net collections and the set of cross-coupling capacitor collections.

Abstract: The present invention includes a method for detecting model stamping errors during circuit simulation without the need for golden data. The method checks for model stamping errors by determining whether entries in model stamping matrices interrelate according to a plurality of preset rules before circuit equations are solved.

Abstract: A method for building a hierarchical representation of a circuit for simulation includes 1) receiving a source file containing SPICE-like netlist descriptions of the circuit in a flattened representation; 2) generating a primitive database using the source file, where the primitive database includes a geometries-describing section for storing a plurality of primitive subcircuit blocks; 3) generating an instance database using the geometries-describing section, where the instances database includes instance subcircuit blocks corresponding to explicitly-expressed primitive subcircuit blocks with predefined geometric values; 4) generating a simulation database using the instance database, where the simulation database includes simulation subcircuit blocks corresponding to fully-flattened instance subcircuit blocks; and 5) simulating the circuit using the simulation database, the instance database, and the primitive database.

Abstract: A method for simulating a circuit includes representing the circuit as a hierarchically arranged set of branches, including a root branch and a plurality of other branches logically organized in a graph. The hierarchically arranged set of branches includes a first branch that has one or more subcircuits and a second branch that has one or more subcircuits. The first branch and second branch are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches, where a subcircuit at a higher hierarchical level includes one or more subcircuits in a lower hierarchical level.

Abstract: A method for simulating analog behavior of a circuit in a simulation system includes representing the circuit as a hierarchically arranged set of branches, which includes a root branch and a plurality of other branches logically organized in a graph. The hierarchically arranged set of branches includes a first branch that has one or more subcircuits and a second branch that also has one or more subcircuits. The first branch and second branch are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches.

Abstract: An system and method are disclosed for efficiently approximating analytical circuit device models. A preferred embodiment includes a method for obtaining smooth and accurate approximations of analytical device models, comprising the steps of identifying a first set of measurement units; locating two or more sets of units that neighbor one or more of said measurement units; for each set of the two or more sets of neighbor units, obtaining the union of one or more of said sets of neighbor units and the first set of measurement units; calculating the smoothness of the analytical device model within one or more of said unions; and selecting at least one of said unions within which the analytical device model is the smoothest as the new set of measurement units.