Patents Assigned to Cadence Design Systems
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Patent number: 6618837Abstract: The present invention presents methods for modeling the high frequency and noise characterization of MOSFETs. The models may be readily implemented as part of a SPICE or other simulation in a design flow. In particular, this invention is capable of providing a sub-circuit representation of a MOSFET that can accurately predicate a MOSFET's low frequency, high frequency, and noise characterizations. An interface is described through which a user may simultaneously optimize all of these characterizations. Further, methods are presented for building models that can predicate the variations in MOSFETs due to manufacturing processes and generate a corresponding corner model.Type: GrantFiled: September 14, 2000Date of Patent: September 9, 2003Assignee: Cadence Design Systems, Inc.Inventors: Xisheng Zhang, Hancheng Liang, Zhihong Liu, Jianhe Guo
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Publication number: 20030159121Abstract: A buffer for use in a logic circuit comprises input and output nodes. A first inverter having a first device size is coupled to the input node. A second inverter is coupled in series with the first inverter and with the output node. The second inverter having a second device size at least six times greater than the first device size. It is emphasized that this abstract is provided to comply with the rules requiring an abstract that will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).Type: ApplicationFiled: February 19, 2002Publication date: August 21, 2003Applicant: Cadence Design Systems, Inc.Inventor: Kenneth Hing Key Tseng
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Patent number: 6608860Abstract: An improved transmitter capable of achieving high linearity with minimal power dissipation is disclosed, comprising a digital phase splitter and an output stage. The digital phase splitter includes a positive phase digital-to-analog converter (DAC) for converting the positive phase portion of a set of input digital data into an analog signal, and a negative phase DAC for converting the negative phase portion of the set of input digital data into another analog signal. The analog signals from the phase splitter are passed to the output stage for transmission onto a transmission medium. The transmitter may be operated in low power dissipation mode. Because the phases of the input digital signal are split in the digital domain prior to the output stage, the output stage experiences minimal crossover distortion. Consequently, the transmitter is able to minimize power dissipation without suffering from poor linearity performance.Type: GrantFiled: November 5, 1999Date of Patent: August 19, 2003Assignee: Cadence Design Systems, Inc.Inventors: Eric H. Naviasky, Martin J. Mengele
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Patent number: 6594800Abstract: A method and apparatus for designing a circuit system, including selecting a plurality of pre-designed circuit blocks to be used to design the circuit system, collecting data reflecting the experience of the designer regarding the pre-designed circuit blocks, the designer's experience being adaptable to a processing method, accepting or rejecting a design of the circuit system in a manner based on the designer's experience data and acceptable degree of risk, upon acceptance, forming block specifications containing criteria and modified constraints for each of the circuit blocks, upon acceptance, forming block specifications for deploying the circuit blocks on a floor plan of a chip, as a system on a chip, in compliance with the criteria and modified constraints, and substantially without changing the selected circuit block and the processing method.Type: GrantFiled: January 4, 2001Date of Patent: July 15, 2003Assignee: Cadence Design Systems, Inc.Inventors: Henry Chang, Larry Cooke, Merrill Hunt, Wuudiann Ke, Christopher K. Lennard, Grant Martin, Peter Paterson, Khoan Truong, Kumar Venkatramani
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Patent number: 6594799Abstract: A multi-faceted portal site acts as a server in the context of an n-tier client/server network, and connects electronic designers and design teams to design and verification tool and service providers on the other through a single portal site. Tools and services accessible to users through the portal site include electronic design automation (EDA) software tools, electronic component information, electronic component databases of parts (or dynamic parts), computing and processing resources, virtual circuit blocks, design expert assistance, and integrated circuit fabrication. Such tools and services may be provided in whole or part by suppliers connected to the portal site. Users accessing the portal site are presented with options in a menu or other convenient format identifying the tools and services available, and are able to more rapidly complete circuit designs by having access to a wide variety of tools and services in a single locale.Type: GrantFiled: February 28, 2000Date of Patent: July 15, 2003Assignee: Cadence Design Systems, Inc.Inventors: William H. Robertson, James M. Plymale
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Publication number: 20030131327Abstract: A system and method for testing an integrated circuit having internal circuit blocks. Each of the internal circuit blocks may have its own test circuit block, referred to as a socket access port. The integrated circuit preferably includes a chip access port (e.g., an IEEE standard 1149.1 compliant test access port) connected to a set of boundary-scan cells, and connected in a hierarchical fashion to the lower-level test circuit blocks. Each of the lower-level test control circuit blocks preferably comprises a socket access port controller, and test operation is transferred downward and upwards within said hierarchical structure by communicating from a test control circuit block to the test control circuit block at the immediately higher or immediately lower level in the hierarchical structure. Each of the lower-level test control circuit blocks of the hierarchical test control network may be functionally identical. Further, each of the lower-level test control circuit blocks may be structurally identical.Type: ApplicationFiled: December 20, 2002Publication date: July 10, 2003Applicant: Cadence Design Systems, Inc.Inventors: Bulent Dervisoglu, Laurence H. Cooke
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Publication number: 20030126578Abstract: An automated method and system is disclosed to determine an Integrated Circuit (IC) package interconnect routing using a mathematical topological solution. A global topological routing solution is determined to provide singular ideal IC package routing solution. Topological Global Routing provides a mathematical abstraction of the problem that allows multiple optimizations to be performed prior to detailed routing. Preliminary disregard of electrical routing segment width and required clearance allows the global topological solution to be determined quickly. The global topological solution is used in conjunction with necessary design parameters to determine the optimal geometric routing solution. Guide points are determined using the geometric routing solution. A detail router uses the guide points as comers when performing the actual routing.Type: ApplicationFiled: February 3, 2003Publication date: July 3, 2003Applicant: Cadence Design Systems, Inc.Inventors: Ken Wadland, Glendine Kingsbury
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Publication number: 20030121013Abstract: Disclosed is a method and system for extracting a timing model. One disclosed approach to extract a timing model is by reducing the timing graph. Original timing behavior is preserved in the timing model including arrival times, slew times, timing violations and even latch time borrowing that is independent of clock waveforms. Also, original timing constraints can be captured in the model and be applied automatically when the model is used. Anchor points are automatically identified and retained to obtain a model that is smaller than the original netlist.Type: ApplicationFiled: December 6, 2002Publication date: June 26, 2003Applicant: Cadence Design Systems, Inc.Inventors: Cho Woo Moon, Harish Kriplani, Krishna Prasad Belkhale
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Publication number: 20030120974Abstract: A microcode programmable built-in-self-test (BIST) circuit and method for testing a multiported memory via multiple ports, either simultaneously or sequentially, as directed by a microcode instruction word. The microcode instruction word contains a plurality of executable subinstructions and one bit of information that controls whether the test operations prescribed in the plurality of subinstructions shall be executed in parallel or in series. The executable subinstructions are dispatched by a primary controller to subcontrollers which perform test operations at each port according to the subinstructions. The microcode programable BIST architecture flexibly facilitates the testing of multiple devices, multiported devices, including multiported memory structures and complex dependent multiported memory structures. The BIST supports in-situ testing of the functionality of the memory at wafer, module, and burn-in, as well as system-level testing.Type: ApplicationFiled: January 30, 2003Publication date: June 26, 2003Applicant: Cadence Design Systems, Inc.Inventors: R. Dean Adams, Thomas J. Eckenrode, Steven L. Gregor, Kamran Zarrineh
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Publication number: 20030120474Abstract: Disclosed is a method and system for handling timing constraints or assertions for timing model extraction. One disclosed approach for assertion handling is by automatically preserving the integrity of original assertions by retaining existing pins or creating new internal pins. The assertions are viewed as part of the model, and a set of new assertions are generated automatically as part of the timing model extraction process and can be stored as part of the model. Assertions can be associated with input ports, output ports, internal pins, or hierarchical pins and can even span multiple blocks. This disclosed approach allows for application of assertions associated with timing models when the model is instantiated and detachment of assertions when the model is de-instantiated, and thus removes one of main problems associated with timing models.Type: ApplicationFiled: December 6, 2002Publication date: June 26, 2003Applicant: Cadence Design Systems, Inc.Inventors: Cho Woo Moon, Harish Kriplani, Krishna Prasad Belkhale
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Publication number: 20030115564Abstract: A method and apparatus for designing a circuit system, including selecting a plurality of pre-designed circuit blocks to be used to design the circuit system, collecting data reflecting the experience of the designer regarding the pre-designed circuit blocks, the designer's experience being adaptable to a processing method, accepting or rejecting a design of the circuit system in a manner based on the designer's experience data and acceptable degree of risk, upon acceptance, forming block specifications containing criteria and modified constraints for each of the circuit blocks, upon acceptance, forming block specifications for deploying the circuit blocks on a floor plan of a chip, as a system on a chip, in compliance with the criteria and modified constraints, and substantially without changing the selected circuit block and the processing method.Type: ApplicationFiled: March 23, 2001Publication date: June 19, 2003Applicant: Cadence Design Systems, Inc.Inventors: Henry Chang, Larry Cooke, Merrill Hunt, Wuudiann Ke, Christopher K. Lennard, Grant Martin, Peter Paterson, Khoan Truong, Kumar Venkatramani
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Method and arrangement for extracting capacitance in integrated circuits having non Manhattan wiring
Patent number: 6581198Abstract: The present invention introduces a method of quickly extracting the capacitance for interconnect wires in an integrated circuit routed with a non Manhattan architecture. To extract the capacitance a section containing non Manhattan wiring, the present invention proposes an approximation system that approximates the section of non Manhattan wiring with a Manhattan wiring section that has a capacitance per unit length that is generally proportional to the length of the approximated section. The capacitance affect from the approximated Manhattan wiring section is then adjusted with a correction factor.Type: GrantFiled: June 13, 2001Date of Patent: June 17, 2003Assignee: Cadence Design Systems, Inc.Inventors: Steven Teig, Arindam Chatterjee -
Patent number: 6578174Abstract: A multi-faceted circuit design platform facilitates the design of circuits and chips by making it easier for designers to locate and incorporate available virtual component blocks into new designs. The platform provides designers with the necessary support data on the virtual component blocks and allows designers to perform integration and connectivity verification as well as basic functional verification. In addition, the platform may provide other tools and services, e.g., electronic design automation software, computing and processing resources, integrated circuit fabrication, etc. The tools and services may be from internal as well as external sources and may be provided in whole or in part. Further, the platform may facilitate purchase, lease, or other acquisitions of the tools and services offered through it. Access to the platform may be achieved through a variety of applications.Type: GrantFiled: June 8, 2001Date of Patent: June 10, 2003Assignee: Cadence Design Systems, Inc.Inventor: Claudio Zizzo
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Patent number: 6574778Abstract: A method and apparatus for designing a circuit system, including selecting a plurality of pre-designed circuit blocks to be used to design the circuit system, collecting data reflecting the experience of the designer regarding the pre-designed circuit blocks, the designer's experience being adaptable to a processing method, accepting or rejecting a design of the circuit system in a manner based on the designer's experience data and acceptable degree of risk, upon acceptance, forming block specifications containing criteria and modified constraints for each of the circuit blocks, upon acceptance, forming block specifications for deploying the circuit blocks on a floor plan of a chip, as a system on a chip, in compliance with the criteria and modified constraints, and substantially without changing the selected circuit block and the processing method.Type: GrantFiled: January 4, 2001Date of Patent: June 3, 2003Assignee: Cadence Design Systems, Inc.Inventors: Henry Chang, Larry Cooke, Merrill Hunt, Wuudiann Ke, Christopher K. Lennard, Grant Martin, Peter Paterson, Khoan Truong, Kumar Venkatramani
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Patent number: 6567957Abstract: A method and apparatus for designing a circuit system, including selecting a plurality of pre-designed circuit blocks to be used to design the circuit system, collecting data reflecting the experience of the designer regarding the pre-designed circuit blocks, the designer's experience being adaptable to a processing method, accepting or rejecting a design of the circuit system in a manner based on the designer's experience data and acceptable degree of risk, upon acceptance, forming block specifications containing criteria and modified constraints for each of the circuit blocks, upon acceptance, forming block specifications for deploying the circuit blocks on a floor plan of a chip, as a system on a chip, in compliance with the criteria and modified constraints, and substantially without changing the selected circuit block and the processing method.Type: GrantFiled: January 4, 2001Date of Patent: May 20, 2003Assignee: Cadence Design Systems, Inc.Inventors: Henry Chang, Larry Cooke, Merrill Hunt, Wuudiann Ke, Christopher K. Lennard, Grant Martin, Peter Paterson, Khoan Truong, Kumar Venkatramani
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Patent number: 6562638Abstract: A method for determining device yield of a semiconductor device design, includes determining statistics of at least one MOSFET parameter from a gate pattern, and calculating device yield from the at least one MOSFET parameter. The method provides a direct simulation link from device layout to device performance.Type: GrantFiled: December 29, 2000Date of Patent: May 13, 2003Assignees: Cypress Semiconductor Corp., Cadence Design Systems, Inc., Sequoia Design SystemsInventors: Artur Balasinski, Robert C. Pack, Valery Axelrad, Victor Vladimir Boksha
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Patent number: 6560755Abstract: An exemplary method for simulating the effect of mismatch in design flows comprises receiving measured data, receiving an original model, extracting a mismatch model based on the measured data and the original model, attaching the mismatch model to the netlist to obtain a modified netlist, and simulating an effect of mismatch based on the modified netlist. In one embodiment, the extracting of a mismatch model includes selecting a set of model parameters, generating a distribution of mismatch values for each of the model parameters, extracting a set of linking coefficients based on said mismatch values, and extracting said mismatch model based on said set of linking coefficients.Type: GrantFiled: August 24, 2000Date of Patent: May 6, 2003Assignee: Cadence Design Systems, Inc.Inventors: Xisheng Zhang, James Chieh-Tsung Chen, Zhihong Liu, Jushan Xie, Xucheng Pang, Jingkun Fang
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Patent number: 6557127Abstract: A method and system for testing multiported memories, especially when one or more of the ports are not directly accessible without intervening logic. The method and system segregates the multiported memory into at least two portions which are then used for testing the one or more ports which are not directly accessible.Type: GrantFiled: February 28, 2000Date of Patent: April 29, 2003Assignee: Cadence Design Systems, Inc.Inventors: R. Dean Adams, Thomas J. Eckenrode, Steven L. Gregor, Kamran Zarrineh
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Patent number: 6543041Abstract: Described is a method for forming a physical layout on a chip floor for a circuit design based on a netlist. The method tentatively places each of the gates of the netlist to a physical location on the chip floor. The method then estimates potential signal integrity and reliability problems. If the placed net list is not acceptable for not being able to meet the requirements of the circuit design, the method modifies the netlist and re-places each of the gates in the modified netlist into a physical location on the chip floor. The method then re-estimates the potential signal integrity and reliability problems. The method repeats this process until the estimation to the-placed or re-placed netlist is acceptable for being able to meet the requirements of the circuit design.Type: GrantFiled: June 15, 1999Date of Patent: April 1, 2003Assignee: Cadence Design Systems, Inc.Inventors: Louis K. Scheffer, Jeffrey S. Salowe
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Patent number: 6543043Abstract: A system and method for routing wires using an automated circuit design tool includes a process for order negotiation to adjust the ordering of wires back and forth between conduits by considering both inter-region and intra-region constraints on the layout of the wires. Order negotiation is preferably carried out by looking both forward and backward during the processing of channels, and by flexibly accounting for intra-region, crosstalk, and grouping constraints, as well as conduit exit constraints. Pairs of nets within a conduit are classified in different categories, including (1) having internal constraints, and (2) not having internal constraints. Nets having internal constraints are generally used in order negotiation for limited purposes (e.g., breaking a loop), whereas nets having no internal constraints are generally used in order negotiation for a variety of other purposes as well, including improving the layout of other conduits.Type: GrantFiled: June 1, 2000Date of Patent: April 1, 2003Assignee: Cadence Design Systems, Inc.Inventors: Xiao-Dong Wang, David Chyan