Editing Application-specific integrated circuit (section)

== Full-custom design ==
{{Main|Full custom}}
[[File:VLSI VL82C486 Single Chip 486 System Controller HV.jpg|thumb|Microscope photograph of custom ASIC (486 chipset) showing gate-based design on top and custom circuitry on bottom]]

By contrast, full-custom ASIC design defines all the photolithographic layers of the device.<ref name="MichaelJohnSebastianSmith"/> Full-custom design is used for both ASIC design and for standard product design.

The benefits of full-custom design include reduced area (and therefore recurring component cost), [[Computer performance|performance]] improvements, and also the ability to integrate [[Analog signal|analog]] components and other [[Semiconductor intellectual property core|pre-designed]]—and thus fully verified—components, such as [[microprocessor]] cores, that form a [[system on a chip]].

The disadvantages of full-custom design can include increased manufacturing and design time, increased non-recurring engineering costs, more complexity in the [[computer-aided design]] (CAD) and [[electronic design automation]] systems, and a much higher skill requirement on the part of the design team.

For digital-only designs, however, "standard-cell" cell libraries, together with modern CAD systems, can offer considerable performance/cost benefits with low risk. Automated layout tools are quick and easy to use and also offer the possibility to "hand-tweak" or manually optimize any performance-limiting aspect of the design.

This is designed by using basic logic gates, circuits or layout specially for a design.