Methodology for the Design of Analog Integrated Interfaces Using Contracts

The design of complex analog interfaces would largely benefit from model-based development and compositional methods to improve the quality of its final result. However, analog circuit behaviors are so tightly intertwined with their environment that: 1) abstractions needed for model-based design are often not accurate, thus making it difficult to achieve reliable system performance estimations, and 2) generic, design-independent interfaces that are needed to develop compositional techniques are very difficult to define. In this paper, we propose a platform-based design methodology that uses analog contracts to develop reliable abstractions and design-independent interfaces. A contract explicitly handles pairs of properties, representing the assumptions on the environment and the promises of a component under these assumptions. Horizontal contracts encode composition rules that constrain how library elements should be "legally" used. Vertical contracts define under which conditions an aggregation of components satisfies the requirements posed at a higher level of abstraction. If both sets of contracts are satisfied, we can produce implementations by composition and refinement that are correct by construction. We demonstrate the effectiveness of this approach on the design of an ultra-wide band receiver used in an Intelligent Tire system, an on-vehicle wireless sensor network for active safety applications.