An application-specific integrated circuit (ASIC) is an integrated circuit (IC) that has been customized for a specific use. For example, a chip designed solely to run in a GPS is an ASIC.

Following Moore's Law, a maximum ASIC sizes have grown from 5,000 gates to over 100 million. Modern ASICs often include entire 32-bit processors, ROM, RAM, EEPROM, Flash and other large building blocks. In certain circumstances, such an ASIC may be called an SoC (System-on-a-chip).

ASIC are designed using a hardware description language (HDL), (eg: Verilog or VHDL), to describe ASIC functionalities.

ASIC designs allow the designer to squeeze in more circuitry onto a single chip than if the circuits had been assembled using proprietary chips - which would require more components and board area. This allows lower manufacturing costs, performance, and even some chip designs that would not be technically possible using discrete components.

The key aspects of ASIC design are correct functionality, cost and time-to-market.