The ASIC refers to Application Specific Integrated Circuits is basically a microchip which has been made for a particular application. This integrates circuit is created for specific applications like the RAM chips in the PC. The ASIC can be employed in multiple applications and is found in nearly every electronic device. It can be used for many purposes, even environmental monitoring, auto-emission control, and PDAs or personal digital assistants.
When compared with programmable logic devices, the ASIC is capable of improving speeds as they have been designed to cater to a single purpose only. Another advantage of this is that it consumes lesser electricity. However, the drawback is that it is costly to design and make, especially when you need a few units. The ASIC is custom made and it is thus only available to the company which has designed and manufactured it. So, in short, it is proprietary technology.
The ASIC can also be pre-made for special applications or they can be tailor-made for specific client applications. There are 3 categories of ASIC, namely the full-custom ASIC which are tailor-made from scratch for definite applications. The designer decides their use. There is an also a semi-custom ASIC which is partly customized; these ASICs will allow some changes during the manufacturing process. Finally, you will get the platform ASIC which are designed and made from specific methodologies. These are made from well-defined designs of silicon which can reduce design cycles and cut down development costs.