This insatiable push from consumers has seen the number of transistors on-chip continuing to increase, at almost the level defined by Moore’s law. To make these new generations of ICs, even more sophisticated fabs are opening up – which, in turn, has left the world with many fabs that are no longer quite at the cutting edge. Designers may often see these fabs as outdated, but the production technology is proven and could present an opportunity to produce better products.
Custom mixed silicon chips on the cheap
These cheaper fabs offer an excellent opportunity for designers to integrate functions of their project into a single chip or custom chipset solution. The custom IC would be able to provide a perfect match for the application’s requirements. Designers are often put off using custom silicon because of the perceived costs and complexities of mixing analog and digital technologies in a single IC. Implementing the technology has often been thought of as expensive, and only suitable for large projects. However, this perception is not necessarily true, due to the excess capacity of fabs that are set up to use older process technologies.
Industry analyst Gartner has performed research which demonstrates that the cost of the development of custom ICs rises in an almost exponential manner as we get closer to the latest silicon geometries. This cost explosion is especially true for the associated design and embedded software costs. But the curve also offers a sweet spot for many applications, where sufficient performance can be achieved at an economical cost. For most IIoT designs, that sweet spot can be anywhere from 0.18 um to 65 nm – but this sweet spot is not static, as every time that technology moves forward, the sweet spot moves too. In the sweet spot, costs are kept low due to the extra capacity available. These processes are also mature, meaning that any yield issues have already been resolved, which makes lead times more reliable.
So, what benefits can you expect to achieve from a custom IC using an economical, proven silicon technology? Firstly, BOM savings can be extensive – up to 80% in some cases. The custom IC makes designs more compact and offers a higher level of security, as well as higher performance and better power efficiency. The custom silicon also allows designers to add additional functionality, differentiating the design, while protecting the design IP from reverse engineering by competitors. Together, these benefits will ensure a longer profitable shelf-life for the end product.
Further cost savings
In general, the main lesson is that leading-edge IC technology isn’t the best solution for every application, which also can be a decent rule of thumb for other areas of design. Leading-edge is sometimes jokingly termed bleeding-edge, as often low yields and delays in production can bleed the project dry. To put it succinctly, leading-edge technologies cost much more, and not just for production. Using an older geometry takes away a lot of the potential headaches; for example, designers using older geometry providers can have access to extensive libraries of proven IP, which can in itself provide enormous cost benefits.
If you decide to take the custom IC route, it is often better to work with a partner than to attempt the whole project alone. The ideal partner should have extensive experience in the field. For example, S3semi has 20 years of experience in designing analog and mixed-signal custom silicon, and can help walk you through the complete process. S3semi can be the perfect partner to help you realise large cost savings by providing easy access to the most economical production facilities, which allow you to access the higher performance, lower power and proven yield of low-cost custom silicon.