Gate array
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A Gate array or Uncommitted Logic Array (ULA) is an approach to the design and manufacture of application-specific integrated circuits (ASICS). A gate array circuit is a prefabricated circuit with no particular function in which transistors, standard logic gates, and other active devices are placed at regular predefined positions and manufactured on a wafer, usually called master slice. Creation of a circuit with a specified function is accomplished by adding metal interconnects to the chips on the master slice late in the manufacturing process, allowing the function of the chip to be customised as desired.
Gate array master slices are usually prefabricated and stockpiled in large quantities regardless of customer orders. The fabrication according to the individual customer specifications may be finished in a shorter time compared with standard cell or full custom design. The gate array approach reduces the mask costs since fewer custom masks need to be produced. In addition manufacturing test tooling lead time and costs are reduced since the same test fixtures may be used for all gate array products manufactured on the same die size.
Drawbacks are somewhat low density and performance than other approaches to ASIC design. However this style is often a viable approach for low production volumes.
An evolution of this approach is field-programmable gate arrays.