Power-driven FPGA to ASIC Conversion

Gate arrays are often presented as a convenient means for ASIC prototyping. Obviously, they can both perform the same function and therefore be built from the same behavioral description. Design development implies a process of subsequent parameter bindings, leaving steadily less freedom for the remaining implementation choices. On the other hand, the ASIC offers more place & route freedom than the gate array. Hence it is commonly suggested that an optimal prototype will always have an acceptable ASIC realization. But this does not make the gate array an easy stepping-stone in ASIC development. Differences in platform technology induce a different structural sugaring to achieve a reasonable implementation. This cannot easily be ported, unless the implementation is developed while keeping the restrictions for the other technology in mind. Such implies a number of scaling rules to be the foundation of the design transformation process. This paper looks into the platform commonalities of Field-Programmable Gate-arrays and standard-cell ASICs from fundamental physical principles. These basic considerations are then related to show how the area and speed restrictions in the logic synthesis can be applied to carry power efficient designs efficiently from prototype to realization. This is illustrated in the design of the SNOW-2 encryption core, where a consistent 38% power reduction is achieved.