Construction of analog library cells for analog/digital ASICs using novel design and modular assembly techniques

Efforts to improve the tools and techniques for designing an analog cell library for analog/digital VLSI design are described. The techniques presented allow an analog IC designer to construct a library for cell-based design, as opposed to direct compilation of a full-custom analog/digital IC. Using this approach, the problem of automation is made more tractable, and the result is a more robust, but still flexible, system for mixed analog/digital ASIC (application-specific integrated circuit) design. By combining a study of device scaling issues, careful choice of layout topologies, together with modular construction of cells using lambda based rules, it is possible to extend the lifetime of an analog cell library. Cells have been constructed for both 2- and 1.5-μm down-gate-width technologies with the ability to scale down to a 1-μm process