A MODULE GENERATION ENVIRONMENT FOR MIXED-SIGNAL CIRCUITS
H. Sampath · OhioLink ETD Center (Ohio Library and Information Network) · 2003
Mixed-signal systems have resulted from the integration of analog and digital systems on the same chip.In most mixed-signal integrated circuits, the analog component is used as the interface while the internal signal processing is done in the digital domain.In digital, analog and mixed-signal systems, the performance of the system depends on the quality of the layout.As the frequency of operation of systems increases, the layout influences on the system performance are higher than before.Layout parasites, variations in device sizes, symmetry and matching constraints affect performances, more so in analog systems than digital.Modules can be defined as devices or groups that have a certain functionality.Though the number of such basic building blocks is limited, a number of variants -that differ greatly in their functionality and physical realizations -exist.These variants are usually obtained by changing certain properties of the circuit/device.Each variant can also have a number of possible aspect ratios or shapes.The presence of good module generators, that allow quick development and easy specification of parameterized modules, considerably improves the quality of layouts.This thesis provides an environment for specification of highly parameterized modules through the Module Specification Language (MSL).The language has been adapted to module generation with an intuitive and easy-to-read structure.It also allows designers to easily incorporate their domain specific knowledge into the modules.The language allows modules to be hierarchically composed of other modules, thus promoting re-use of previously defined modules.Though rules for a particular technology must be obeyed while writing modules, use of aliases for physical layers provides some technology-independence to the modules.The language itself is independent of the module being specified, making it useful for the development of both analog and digital modules.Constructs specifically aimed at improving the quality of analog layouts are provided in the language.The module generation environment lends itself very well to layout generation as well, through the use of routing modules defined in the language or through external routers.On account of its design, the generation environment allows for integration with a variety of CAD tools.The tool currently works with both Magic and Cadence Virtuoso layout editors and can also be interfaced with other layout editors.To validate the tool and the language, an extensive library of parameterized modules was specified and tested through simulations and through use with other tools.