A Top Down, Constraint-Driven Design Methodology for Analog Circuits and Systems

The analog section of a complex mixed-signal system is often small, but also the one that consumes the most time. Unlike its digital counterpart, fully automatic synthesis tools are simply not available. The principle goal of this project is to define a new design methodology and the necessary set of CAD tools supporting it to accelerate the process of analog design.

The key points in the design methodology are:

a top-down hierarchical process starting at the behavioral level based on early verification and constraint propagation,

bottom-up extraction and verification of functionality parameters,

automatic and interactive synthesis tools to accommodate different levels of expertise, without forcing the tools upon the user

and consideration for testability at all stages of the design.

This methodology provides two principal advantages-- a high probability for first silicon which meets all specifications and fast design times. Once the tools have been developed for a certain class of circuits and the first design has been done, the redesign for a different set of specifications is vastly accelerated. Design examples have already been manufactured and the results have been published. In addition to the current source interpolative D/A Converter and Sigma-Delta A/D design examples, a Display Driver System example was completed in 1996. The chip was tested and specifications were met thus validating once more our methodology. The latter system was the most complex among the ones considered so far. Hence, the design of complex mixed-signal systems was illustrated and we provided a rigorous approach together with the behavioral and noise simulation tools that support it.