SemiEngineering Article: Why IP Quality Is So Difficult to Determine

7 Jun 2019 • 3 minute read

Differentiating good IP from mediocre or bad IP is getting more difficult, in part because it depends upon how and where it is used and in part, because even the best IP may work better in one system than another—even in chips developed by the same vendor.

So, how do you measure IP quality and why it is so complicated?

The answer depends on who is asking. Most of the time, the definition of IP quality depends on your vantage point. If you are an R&D manager, IP quality means something. If you are a global supply manager, IP quality means something else. If you are an SoC start-up, your measure of quality is quite different from that of an established fabless company. If you are designing IP in-house, then your considerations are very different than being a commercial IP vendor. If you are designing an automotive SoC, then we are in a totally different category. How about as an IP vendor? How do you articulate IP quality metrics to your customers?

This varies greatly by the type of IP, as well. When it comes to interface (hard) IP and controllers, if you are an R&D manager, your goal is to design IP that meets the IP specifications and PPA (power, performance, and area) targets. You need to validate your design via silicon test chips. This applies to all hard PHYs, which must be mapped to a particular foundry process. For controllers that are in RTL form—we called these soft IP—you have to synthesize them into a particular target library in a particular foundry process in order to realize them in a physical form suitable for SoC integration. Of course, your design will need to go through a series of design validation steps via simulation, design verification and passing the necessary DRC checks, etc. In addition, you want to see the test silicon in various process corners to ensure the IP is robust and will perform well under normal process variations in the production wafers.

For someone in IP procurement, the measure of quality will be based on the maturity of the IP. This involves the number of designs that have been taped out using this IP and the history of bug reports and subsequent fixes. You will be looking for quality of the documentation and the technical deliverables. You will also benchmark the supplier’s standard operating procedures for bug reporting and technical support, as well as meeting delivery performance in prior programs. This is in addition to the technical teams doing their technical diligence.

An in-house team that is likely to design IP for a particular SoC project will be using an established design flow and will have legacy knowledge of last generation’s IP. They may be required to design the IP with some reusability in mind for future programs. However, such reusability requirements will not need to be as stringent and as broad as those of commercial IP vendors because there are likely to be established metrics and procedures in place to follow as part of the design team’s standard operating procedures. Many times, new development based on a prior design that has been proven in use will be started, given this stable starting point. All of these criteria help the team achieve a quality outcome more easily.

Then, if designing for an automotive SoC, additional heavy lifting is required. Aside from ensuring that the IP meets the specifications of the protocol standards and passes the compliance testing, you also must pay attention to meeting functional safety requirements. This means adherence to ISO 26262 requirements and subsequently achieving ASIL certification. Oftentimes, even for IP, you must perform some AEC-Q100-related tests that are relevant to IP, such as ESD, LU, and HTOL.