Optimization Environment Enables Effective Reuse of Existing Design Modules

In order to complete a brand new design on time, it is an important factor to effectively reuse existing design modules. The use of an automatic optimization quickly and easily increases design reuse efficiency. The following figures are examples of a source layout and an optimized result made by Virtuoso Layout Migrate. Virtuoso Layout Migrate optimizes a design automatically by satisfying design specific constraints. The shape of the source layout can be maintained in the optimization result perfectly.

Before Migrate

After Migrate

One important issue that we need to carefully consider is how easily the result can be obtained. Even though the high quality optimization is possible, it would be useless if a lot of work is required to get it.

Cadence’s Virtuoso_XL, and GXL automatically extracts design constraints including Symmetry placement required for a design optimization from connectivity information in a schematic view and delivers them to a layout view via Constraint Manager. The design constraints delivered to the layout view will be applied as well as constraints added by a user manually during the optimization.

This optimization flow is as follows.

The following Fig 1-a shows the contrarians extracted by Circuit prospector. Fig 1-b is a migration result with respecting the design constraints extracted by Circuit prospector, and added by the constraint manager.

     Fig 1-a. Automatic design specific constraints extraction by Circuit Prospector

Fig 1-b. Automatic design constraints addition via Constraint Manager (Schematic -> Layout)

Cadence Virtuoso XL, GXL can easily and automatically achieve extracting, maintaining, and applying complex design specific constraints that was "impossible" a decade ago. Cadence is only company offers robust, and comprehensive integrated design re-use flow in Virtuoso XL, GXL.

Hiroshi Ishikawa