A design system for RFIC: challenges and solutions

The expansion of the market for portable wireless communication devices has given a tremendous push to the development of a new generation of low-power radio frequency integrated circuit (RFIC) products. In this fast-growing environment where time-to-market constraints force tight schedules, having a good design methodology, innovation computer-aided design (CAD) tools, and a well-integrated design system are key factors for success. In this paper, we describe a design system developed to provide the designer with everything necessary to accurately predict the behavior of RFIC devices, including layout and package parasitic effects. We show how important a well-defined and integrated system is to manufacturing a design that meets specifications at the minimum cost, in the minimum time. A close link between schematic, models, and layout is of paramount importance to ensure the accuracy need for low-power RF design. We give an overview of the advanced methods and tools currently available for simulation and noise analysis of RF devices. Finally, we show a design example that obtained first-silicon success     

A Novel Generic Model at Asperity Level for Dry Friction Force Dynamics

This paper presents a theoretical model for (dry, low-velocity, wear-less) friction force dynamics based on asperity interaction considerations subject to the phenomenological mechanisms of creep/relaxation, adhesion and (elasto-plastic) deformation in their most generalized forms. The model simulates the interaction of a large population of idealized, randomly distributed asperities with arbitrarily chosen geometrical and elastic properties. Creep and adhesion are simulated by an expedient local coefficient of friction that increases with time of contact, while deformation effects are accounted for by rate-independent hysteresis losses occurring in the bulk of the material of an asperity that is breaking loose. An energy method is adopted to calculate the instantaneous, local friction force leading to better insight into the problem as well as higher numerical efficiency. The results obtained by this model show both qualitative and quantitative agreement with the known types and facets of friction force dynamic behaviour; in particular, pre-sliding quasi time-independent frictional hysteresis in the displacement, velocity weakening, slider “lift-up” effect and frictional lag, in addition to the influence of the various process parameters, all in a single formulation, such as no extant friction model could show before. Moreover, the model is still open for and capable of further refinement and elaboration so as to incorporate local inertia and viscous effects and thus to be extended to include velocity strengthening and lubricated rough contacts.     

Modification of the Leuven integrated friction model structure

This note presents a modification of the integrated friction model structure proposed by Swevers et al. (2000), called the Leuven model. The Leuven model structure allows accurate modeling both in the presliding and the sliding regimes without the use of a switching function. The model incorporates a hysteresis function with nonlocal memory and arbitrary transition curves. This note presents two modifications of the Leuven model. A first modification overcomes a recently detected shortcoming of the original Leuven model: a discontinuity in the friction force which occurs during certain transitions in presliding. A second modification, using the general Maxwell slip model to implement the hysteresis force, eliminates the problem of stack overflow, which can occur with the implementation of the hysteresis force     

A broad-band lumped element analytic model incorporating skin effect and substrate loss for inductors and inductor like components for silicon technology performance assessment and RFIC design

We present a broad-band lumped element planar inductor model that is suitable for RFIC design in silicon technologies. We provide extensions of the modeling methodology to similar components such as differential inductors, baluns, and solenoid inductors. The analytic computation of the physics-based model components, incorporating both metal skin effect and substrate loss, is described. The model is validated using measured data from over 200 inductors made with five different silicon back-end process technologies. The physics-based implementation of the model allows its use for determining the optimum process technology characteristics for specific radio frequency integrated circuit (RFIC) designs. The analytical based implementation with lumped elements enables effective integration into a robust CAD system for efficient design of RFIC circuits.     

Experimental Characterization of Dry Friction at Low Velocities on a Developed Tribometer Setup for Macroscopic Measurements

Tribology Letters - This paper presents some experimental evidence of dry friction behavior at low velocities. The experiments are carried out on a tribometer developed by the authors, where the...     

An analogue module generator for mixed analogue/digital asic design

This paper discusses the realization of an analogue module generator that forms part of a mixed analogue/digital design environment. It is able to design analogue functional modules such as like amplifiers, filters, etc., either in an automatic or in an interactive session, starting from performance specifications over topology selection, parameter optimization and simulation/verification down to lay-out. the analogue module generator is integrated in a commercial EDA framework. Practical design results show the capabilities and efficiency of the system.     

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A performance-driven placement tool for analog integrated circuits

This paper presents a new approach toward performance-driven placement of analog integrated circuits. The freedom in placing the devices is used to control the layout-induced performance degradation within the margins imposed by the designer's specifications. This guarantees that the resulting layout will meet all specifications by construction. During each iteration of the simulated annealing algorithm, the layout-induced performance degradation is calculated from the geometrical properties of the intermediate solution. The placement tool inherently handles symmetry constraints, circuit loading effects and device mismatches. The feasibility of the approach is demonstrated with practical circuit examples     

Nonlocal hysteresis function identification and compensation with neural networks

This paper discusses the on-line identification of nonlocal static hysteresis functions, which are encountered in mechanical friction, magnetic materials, and piezoelectric actuators and cause problems in the design of controllers. In this article a new compensation method for friction in presliding regime is introduced that is based on the simplified Leuven Friction Model and on technology borrowed from neural networks. We present a solution how to identify the hysteresis caused by the friction and how to use this identified model for the compensation of the friction effects. The solution can be used for on-line identification and compensation. Results from both simulations and experiments will be shown.