The ASIC acronym stands for Application Specific Integrated Circuits, which refers to an integrated circuit (IC or chip) tailored or customized for a specific purpose. A good example would be an ASIC designed to control the brake system in a car – this chip is designed only for this specific application.
ASICs are manufactured using metal oxide semiconductors (MOS) technology. The size of the features has shrunk, and the design tools have improved, allowing the inclusion of over 100 million logic gates a single ASIC and thus increasing the complexity and functionality of the ASICs.
Standard ICs are off-the-shelf-chips designed and produced by 3rd party vendors. These chips have fixed price and functionality. ASICs are home brewed chips that are customized to your needs. To make the comparison very easy to understand, let’s take the discussion to the Pizza market.
You can buy a pizza from the supermarket; this pizza has a fixed price and properties. However, if you are willing to make the investment (and risk), you can bake your own pizza at home. You need to buy all the ingredients and spend the time learning and producing one pizza. This pizza will meet your requirements (taste) perfectly. ASIC is the pizza you make at home. You can make your own ASIC, but you need to decide if you want to take the risk and the capital investment.
ASICs exists in different design structures, which include:
Standard-cell ASIC design
This is the most common ASIC design method today. This design uses standard cells consisting of transistors and interconnecting structures provided by the semiconductor foundry.
Every semiconductor foundry creates functional blocks whose electrical characteristics like capacitance, inductance, and propagation delay are known and uses these functional blocks to create integrated circuits with good electrical performance and high logic gate density.
Full-custom ASIC design
In full-custom ASIC design, the ASICs are designed from the transistors level, and the layout is tailored for the exact requirements of the circuit. Although it takes much longer to design and the costs involved are also higher, this type of ASICs give a very high degree of flexibility, improved performance, and they require a far less area compared to the standard-cell and gate-array designs.
Full-custom ASIC designs also come with higher design cost but the price of the chip in production is the lowest compared to other alternatives.
Structured ASIC design
This design is also referred to as platform ASIC design, and it is a relatively new trend in semiconductors. The design comprises logic mask layers predefined by the ASIC vendor or third party. The design customization and differentiation are attained by making custom metal layers to create custom connections between the lower-layer logic elements already predefined.
Structured ASIC design acts as a bridge between the standard-cell design and field-programmable gate arrays (FPGAs).
Also, the structured ASIC design has a smaller non-recurring expenditure since only a small number of logic mask-layers are custom made compared to the full-custom design where everything is custom-made.
There are several main advantages of ASICs:
ASICs are smaller in size and thus economize on space, which has resulted in many electronic products devices shrinking in size while increasing performance.
Because of their small size, ASIC chips use less electrical power, enabling more products to be battery operated.
Compared to a product based on standard IC, ASICs are not easy to copy. Hence giving you IP protection and the security that your product is safe from copying.
ASICs production price are typically lower than standard IC chips. The upfront investment is high, but if you manufacture the chip in 100Ks unit and more the investment would probably pay off.
