Abstract: Methods and systems are disclosed for determining a yield of a circuit in semiconductor manufacturing. In one embodiment, a computer implemented method includes performing a first pass of Monte Carlo simulations of the circuit to identify a plurality of failed sampling points in a high sigma region of a statistical distribution, partitioning the plurality of failed sampling points into a plurality of clusters based on angular separation of the plurality of failed sampling points, determining a boundary of each cluster in the plurality of clusters, performing sensitivity analysis from the boundary of the each cluster to identify an estimated closest failed sampling point associated with the each cluster, and performing a second pass of Monte Carlo simulations of the circuit to determine the yield of the circuit using the estimated closest failed sampling point associated with the each cluster and the boundary of each cluster in the plurality of clusters.

Abstract: Methods and systems are disclosed related to region based device bypass in circuit simulation. In one embodiment, a computer implemented method of performing region based device bypass in circuit simulation includes receiving a subcircuit for simulation, where the subcircuit includes a plurality of devices, and determining node tolerance of the plurality of devices. The computer implemented method further comprises for each device in the plurality of devices, determining whether the device has entered into a bypass region using the node tolerance of the plurality of devices, performing model evaluation in response to the device has not entered the bypass region, and skipping model evaluation in response to the device has entered the bypass region.

Abstract: Methods and systems are disclosed related to dynamic load balancing in circuit simulation. In one embodiment, a computer implemented method of performing dynamic load balancing in simulating a circuit includes identifying a plurality of simulation tasks to be performed, determining estimated processing durations corresponding to performance of the plurality of simulation tasks, distributing the plurality of simulation tasks to a plurality of processors according to the estimated processing duration of each simulation task, and performing the plurality of simulation tasks at the plurality of processors in parallel.

Abstract: Methods and systems are disclosed related to multi-rate parallel circuit simulation. In one embodiment, a computer implemented method of partitioning the circuit into a plurality of partitions, wherein each partition is represented by a set of linear differential equations, determining a simulation time step for each partition of the plurality of partitions, grouping the plurality of partitions into multiple groups, wherein each group includes one or more partitions having simulation time steps within a predefined range of each other, and solving the multiple groups with their corresponding simulation time steps in parallel.

Abstract: Methods and systems are disclosed for determining a yield of a circuit in semiconductor manufacturing. In one embodiment, a computer implemented method includes performing a first pass of Monte Carlo simulations of the circuit to identify a plurality of failed sampling points in a high sigma region of a statistical distribution, partitioning the plurality of failed sampling points into a plurality of clusters based on angular separation of the plurality of failed sampling points, determining a boundary of each cluster in the plurality of clusters, performing sensitivity analysis from the boundary of the each cluster to identify an estimated closest failed sampling point associated with the each cluster, and performing a second pass of Monte Carlo simulations of the circuit to determine the yield of the circuit using the estimated closest failed sampling point associated with the each cluster and the boundary of each cluster in the plurality of clusters.

Abstract: Method and system are disclosed for repetitive circuit simulation. In one embodiment, a computer implemented method for performing multiple simulations of a circuit includes providing descriptions of connectivity, instants, signal activities, and statistical parameters of the circuit, parsing the circuit in accordance with the descriptions of connectivity, instants, signal activities, and statistical parameters of the circuit to form one or more circuit partitions, performing a first pass simulation of the one or more circuit partitions in accordance with a set of stimuli to generate a history of the first pass simulation, and performing subsequent simulation of the one or more circuit partitions using the history of the first pass simulation.

Abstract: Methods and systems are disclosed related to multi-rate parallel circuit simulation. In one embodiment, a computer implemented method of partitioning the circuit into a plurality of partitions, wherein each partition is represented by a set of linear differential equations, determining a simulation time step for each partition of the plurality of partitions, grouping the plurality of partitions into multiple groups, wherein each group includes one or more partitions having simulation time steps within a predefined range of each other, and solving the multiple groups with their corresponding simulation time steps in parallel.

Abstract: Methods and systems are disclosed related to region based device bypass in circuit simulation. In one embodiment, a computer implemented method of performing region based device bypass in circuit simulation includes receiving a subcircuit for simulation, where the subcircuit includes a plurality of devices, and determining node tolerance of the plurality of devices. The computer implemented method further comprises for each device in the plurality of devices, determining whether the device has entered into a bypass region using the node tolerance of the plurality of devices, performing model evaluation in response to the device has not entered the bypass region, and skipping model evaluation in response to the device has entered the bypass region.

Abstract: Methods and systems are disclosed related to dynamic load balancing in circuit simulation. In one embodiment, a computer implemented method of performing dynamic load balancing in simulating a circuit includes identifying a plurality of simulation tasks to be performed, determining estimated processing durations corresponding to performance of the plurality of simulation tasks, distributing the plurality of simulation tasks to a plurality of processors according to the estimated processing duration of each simulation task, and performing the plurality of simulation tasks at the plurality of processors in parallel.

Abstract: A system for dynamically representing repetitive loads of a circuit during simulation includes a simulator module having one or more computer programs for 1) identifying one or more driver circuits for driving a plurality of repetitive receiver circuits, where each driver circuit has an output port and each repetitive receiver circuit has an input port, 2) creating a branch node driver for connecting the input ports of the plurality of repetitive receiver circuits and the output ports of the one or more driver circuits, 3) creating a shared load for representing aggregated input port loads of the plurality of receiver circuits having a substantially same isomorphic behavior, 4) creating a port connectivity interface for communicating changes of signal conditions between the output ports of the one or more driver circuits and the corresponding input ports of the plurality of repetitive receiver circuits, and 5) simulating the one or more driver circuits and the plurality of repetitive receiver circuits in acco

Abstract: In one embodiment of the invention, a method of simulating a circuit is disclosed including partitioning a circuit into a plurality of blocks, each of the plurality of blocks being radio-frequency blocks or non-radio frequency blocks; performing a first simulation of a first simulation type with the radio-frequency blocks to generate output waveforms of the radio-frequency blocks; performing a second simulation of a second simulation type with the non-radio-frequency blocks to generate output waveforms of the non-radio-frequency blocks where the second simulation type differs from the first simulation type; and synchronizing the first simulation and the second simulation together at one or more time steps to generate output waveforms for the circuit.

Abstract: A computer implemented method is provided for use in evaluating a hierarchical representation of a circuit design encoded in a computer readable medium comprising: traversing a circuit path within a higher level circuit that includes a reference potential connection, to identify a port of a call to a first lower level circuit that is DC path connected to the reference potential; identifying a first DC port group that includes each port of the call to the first lower level circuit that is DC path connected to the identified port of the call to the first lower level circuit; automatically marking as DC path connected to the reference potential, each port of the call to the first lower level circuit that is a member of the first DC port group; and traversing a circuit path within the first lower level circuit to identify a circuit path within the first lower level circuit that is DC path connected to a marked port of the first lower level circuit.

Abstract: A method of determining values for a circuit over a cycle includes: specifying first-cycle values for the circuit in a first cycle, the first-cycle values including voltage or current values for the circuit and providing reference cyclic values for characterizing a cyclic behavior of the circuit in the first cycle with a reference cyclic dimension; determining, from the first-cycle values, path-following values for the circuit in a second cycle, wherein the path-following values include transient values for characterizing a transient behavior of the circuit and cyclic-correction values for characterizing the cyclic behavior of the circuit relative to the reference cyclic values from the first cycle, wherein a cyclic-correction dimension of the cyclic-correction values is less than the reference cyclic dimension; and saving at least some values based on the path-following values in the second cycle.

Abstract: Method and system are disclosed for modeling dynamic behavior of a transistor. The method includes representing static behavior of a transistor using a lookup table, selecting an instance of the transistor from the lookup table for modeling dynamic behavior of the transistor, computing a previous state of the instance using a non-quasi static analytical model, computing a variation in channel charge of the instance according to a rate of change in time, computing a current state of the instance using the previous state and the variation in channel charge, computing a modified terminal voltage that includes a dynamic voltage across a parasitic resistance at the terminal of the transistor according to the current state and previous state of the instance, and storing the modified terminal voltage in a memory device for modeling dynamic behavior of the transistor at the current state.

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: Method and system for partitioning integrated circuits are disclosed. The method includes receiving a netlist representation of the circuit comprising circuit components, partitioning the circuit to form one or more circuit partitions according to a predefined partitioning method, where each circuit partition includes one or more circuit components. The method further includes, for each circuit partition, identifying substantial correlations between the circuit partition and one or more other circuit partitions to form a spanning tree, where the spanning tree connects the circuit partition to the one or more other circuit partitions via a graph, and merging the circuit partition and the one or more other circuit partitions in the spanning tree to form a new circuit partition.

Abstract: Method and system are disclosed for modeling dynamic behavior of a transistor. The method includes representing static behavior of a transistor using a lookup table, selecting an instance of the transistor from the lookup table for modeling dynamic behavior of the transistor, computing a previous state of the instance using a non-quasi static analytical model, computing a variation in channel charge of the instance according to a rate of change in time, computing a current state of the instance using the previous state and the variation in channel charge, computing a modified terminal voltage that includes a dynamic voltage across a parasitic resistance at the terminal of the transistor according to the current state and previous state of the instance, and storing the modified terminal voltage in a memory device for modeling dynamic behavior of the transistor at the current state.

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: 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: A computer implemented method is provided for use in evaluating a hierarchical representation of a circuit design encoded in a computer readable medium comprising: traversing a circuit path within a higher level circuit that includes a reference potential connection, to identify a port of a call to a first lower level circuit that is DC path connected to the reference potential; identifying a first DC port group that includes each port of the call to the first lower level circuit that is DC path connected to the identified port of the call to the first lower level circuit; automatically marking as DC path connected to the reference potential, each port of the call to the first lower level circuit that is a member of the first DC port group; and traversing a circuit path within the first lower level circuit to identify a circuit path within the first lower level circuit that is DC path connected to a marked port of the first lower level circuit.