ASIC
An application-specific integrated circuit (ASIC) is an integrated circuit composed of electrical components, such as transistors, capacitors, and resistors, fabricated on a wafer com-posed of silicon or other semicon-ductor material that is customized for a particular use.
ASIC customized for a particular use, rather than intended for general-purpose use. For example, a chip designed to run in a digital voice recorder or a high-efficiency bitcoin miner is an ASIC. Application-specific standard products (ASSPs) are intermediate between ASICs and industry standard integrated circuits like the 7400 series or the 4000 series.
As feature sizes have shrunk and design tools improved over the years, the maximum complexity (and hence functionality) possible in an ASIC has grown from 5,000 logic gates to over 100 million. Modern ASICs often include entire microprocessors, memory blocks including ROM, RAM, EEPROM, flash memory and other large building blocks. Such an ASIC is often termed a SoC (system-on-chip). Designers of digital ASICs often use a hardware description language (HDL), such as Verilog or VHDL, to describe the functionality of ASICs.
Two examples of ASICs are a voice recorder and a high-efficiency Bitcoin miner. Over the years, the size of components used in ICs has shrunk, meaning that more complex circuits can be cre-ated using the same space. Because of this shrinking of components, some ASICs have now become large enough to contain multiple microprocessors and other complex subsystems.
ASICs and ASSPs are specifically designed for dedicated functionality. Because of the tight control of their configuration, ASICs and ASSPs are very compact, inexpensive, fast, and low-power, which are all highly desirable traits in electron-ics design. Because their function is hard-wired at the time of manu-facture, it isn’t easy to change the functionality of even a small part of the circuit. In fact, because these circuits are permanently fabricated on silicon wafers, you simply can’t take apart the circuitry and replace it with something else. If you need to change something in the design, you have to scrap the whole chip and start again.
