Browsing by Author "Schediwy, Richard Robert"

Now showing 1 - 1 of 1
  • Thumbnail Image
    ItemOpen Access
    A CMOS cell architecture and library
    (1986) Schediwy, Richard Robert; Birtwistle, Graham M.
    One of the major problems faced in VLSI chip design is the potential for overwhelming complexity. Design complexity brings with it long design cycles and wide margins for error. This thesis has developed a partial solution to the problem in the form of a cell library and its associated methodology. A variety of primitive CMOS circuit elements have been designed with generality and longevity in mind. Experience has shown that, when using these cells, the penalties paid in area, power and delay are tolerable. Indeed, the penalties are more than compensated by very rapid design times, process independence and design longevity. The primitive cells are composable into more complex elements, sub-systems and ultimately, complete chips. Primitive cells are designed on a fine grid tuned to generalized CMOS lambda rules. By restricting their borders, port positions and interconnect style, we can abstract all lambda dependent design rule details away at higher levels. Thus, at the composition level, we can work entirely on a coarser grid with the guarantee of being free from lambda design rule errors. The composition rules for the coarse grid are few, simple and easy to enforce. Sub-systems thus composed are regular and compatible and may be retained for use as primitives in the library. The associated methodology provides a top-down design style which can be consistently applied to designing new primitive cells and to composing new sub-systems. It eases some of the problems of complex design by supporting abstraction and composition. The methodology is easy to learn by beginners, easy to use and provides a fundamental broad base for design automation tools. Several chips designed using this methodology have been fabricated and tested. The library is now an established component of the Electric design system and is available through MOS IS.