Cadence Design Systems

About: Cadence Design Systems is a company organization based out in San Jose, California, United States. It is known for research contribution in the topics: Circuit design & Routing (electronic design automation). The organization has 3139 authors who have published 3745 publications receiving 66410 citations. The organization is also known as: Cadence Design Systems, Inc.

Method and system for testing and analyzing user interfaces

Abstract: A system and method is described in which the state of the art in automated software applications is significantly improved. According to some approaches, interface testing is implemented and based upon a verification language and a verification environment. The system and method support the concepts of constrained random test generation, coverage, constrained random generation, and dynamic checks.

ALAPTF: a new transition fault model and the ATPG algorithm

Abstract: The work presents a new transition fault model called as late as possible transition fault (ALAPTF) model. The model aims at detecting smaller delays, which be missed by both the traditional transition fault model and the path delay model. The model makes sure that each transition is launched as late as possible at the fault site, accumulating the small delay defects along its way. Because some transition faults may require multiple paths to be launched, the simple path-delay model miss such faults. Results on ISCAS'85 and ISCAS'89 benchmark circuits shows that for all the cases, the new model is capable of detecting smaller gate delays and produces better results in case of process variations. For all circuits, on an average, 30% of the time the transition reaches later than traditional models. The algorithm proposed also detects robust and non-robust paths along with the transition faults and the execution time is linear to the circuit size.

Multiple-layer contour searching method and apparatus for circuit building block placement

Abstract: Apparatus and methods for two-dimensional compaction of object collections defines an initial set of unrefined objects and an initial compaction direction. One by one, each unrefined object is taken from the unrefined object configuration and placed within a refined configuration. Both unrefined and refined configurations possess profiles along which the selected object is placed. Pruning rules select which locations to investigate more closely, by eliminating those positions that clearly do not provide compaction improvement. Various orientations and/or shapes of an object can be tried to improve the compaction or the group of objects. Once a best location for the object is found, the object is included in the refined object set, new unrefined and refined profiles are constructed, and a new unrefined object is selected to place. Once all unrefined objects have been selected and placed, the compaction process for the chosen direction has completed. The process can continue for other compaction directions, and as many times as required, to compact the collection of objects within a certain tolerance. The cost function employed to determine best object positions can include costs of wire interconnection lengths.

Striving for small-signal stability

Abstract: In this article, based on Bode's definition of return ratio with respect to a single controlled source, the loop-based two-port algorithm and device-based gain-nulling are proposed for small-signal stability analysis. These two algorithms are complementary in terms of applicability, and they produce accurate stability information for single-loop networks. After a brief primer on feedback and stability, we review Bode's feedback theory, where the return difference and return ratio concepts are applicable to general feedback configurations and avoid the necessity of identifying /spl mu/ and /spl beta/. Middlebrook's null double-injection technique, which provides a laboratory-based way to measure return ratio, is then discussed in the modern circuit analysis context; we then extend the unilateral feedback-model used in Middlebrook's approach to accommodate both normal-and reverse-loop transmission and characterize the return loop using a general two-port-analysis. This loop-based two-port algorithm determines the stability of a feedback network in which a critical wire can be located to break all return loops. The device-based gain-nulling algorithm is then discussed to evaluate the influence of the local return loops upon network stability. This algorithm determines the stability of a feedback network in which a controlled source can be nulled to render the network to be passive. Conditions under which these two algorithms can be applied are discussed.

SKILL: a CAD system extension language

Abstract: SKILL is a programming language that supports both command entry and procedural customization in OpusTM Design FrameworkTM. After briefly considering some related work, we examine the requirements that motivate the provision of a programming language available to the user and describe some of the technical characteristics of the language design and implementation. Finally, we describe our experience with the language and outline future work. A number of programming examples are appended.