Application-specific integrated circuit
An application specific integrated circuit (English application- specific integrated circuit, ASIC, and custom chip) is an electronic circuit that has been realized as an integrated circuit. The function of an ASIC is no longer manipulated, the manufacturing costs are lower at this high non-recurring costs (eg, photo masks). ASICs are produced worldwide by many manufacturers to customer requirements and normally delivered only to this. This ASIC of other microchips is different. If a developed as an ASIC chip sold on market, it is often called an application-specific standard product ( ASSP).
Description
Pure digital ASICs integrate a large number of logic functions which must be compiled from a variety of standard components such as processor, logic families (eg 74xx ) or similar building blocks otherwise. Mixed-signal ASIC consist of digital and analog functions. The analog circuits such as analog -to-digital converters, PLLs, low noise amplifiers, high-current drivers, etc. the target technology ( structure size ) determine.
ASICs are used primarily for built in large series devices to reduce costs. A majority of the chips being produced today are application specific, such as the processors used in mobile phones for coding of signals or for processing of data. The difference between PLDs and Field Programmable Gate Arrays is that the functionality of the application-specific ICs must be clearly defined by the manufacturer and is thus fixed. The internal circuit can not be changed by the user. There are also variants ASIC on which microprocessors or signal processors are integrated ( system-on -a-chip ), whereby a certain degree of flexibility for the user can be reached by the software running thereon.
For the design of ASICs is now used EDA (EDA = Electronic Design Automation ).
The known CPU (Intel Pentium or AMD Athlon, etc.) are universal, however, integrated circuits that can handle a variety of tasks. However, this has the disadvantage that these tasks are not executed optimally: energy consumption, data rate, chip area, the clock frequency and other target parameters are higher than in a specialized device in certain applications.
A CPU that is manufactured for a specific task is called application-specific instruction -set processor (ASIP ).
Pros and Cons
Due to the adaptation of their architecture to a specific problem ASICs work very efficiently and much faster than a functionally equivalent implementation in software in a microcontroller. In a mobile phone that has, for example, the advantage that the battery lasts longer and the unit is compact.
Due to their exclusivity ASICs prevent replicas. For hobbyists and service workshops ASICs are often a big problem since they are usually no longer produced after the production of the device has been set. Are the remaining stocks depleted, repair is usually possible only by removing the ASICs from devices plus other defects.
The major disadvantages of ASICs are the longer development time compared to a solution of the same task with discrete components and standard integrated circuits or programmable devices such as FPGAs with especially in small and medium quantities, the high investment costs and, in any case.
Application
ASICs are used in many electronic devices, from clock radios to high-performance computers. The reason for the development of such ICs, which are often even designed for only one specific model, the cost savings over the design using standard building blocks, especially at high production rates. In the early days of integrated circuits ASICs were an alternative to implementation of individual transistors or TTL devices. With digital ASICs are ICs that have been designed for a specific purpose. Most of these devices operate either space, consumption, cost, or performance optimized.
Examples:
- GPUs
- Agnus (ASIC Commodore Amiga)
- Sinclair Computer Logic