Do Your EDA Tools Cost More than your Engineers?

By John Tanner, President and CEO, Tanner EDA

 

EDA tools from the big three vendors can cost as much as an experienced engineer in the U.S., Europe, or Japan. As some design activities move to lower-wage countries, the cost of the tools may become unacceptable. But some EDA companies are filling this gap with powerful, affordable tools.

The Cost-Reduction Challenge

There is increasing pressure on semiconductor companies to control design costs. Mask fabrication, design engineering labor, and EDA tools are the three major contributors to design cost.

Although mask costs are an issue for all types of design, the differences between all-digital and mixed-signal design costs are the result of different market forces. Digital design engineers have benefited significantly from the automation offered by expensive, high-end EDA tools.

The dynamic for mixed-signal design and smaller digital chips is somewhat different, especially for the majority of chip designs that are manufactured in medium to low volume. Here, in many cases, companies must contain their labor costs and their expenditures on EDA tools in order to survive. Under competitive pressure, larger companies have offshored some of their design work by opening wholly owned design centers in countries with lower wages.

Along with these changes comes greater pressure on EDA costs. Companies designing high-volume digital chips have often been willing to pay about $100,000 per year for software to be used by an engineer who is paid the same amount annually. But reducing the cost of the engineer to $20,000 per year by offshoring or outsourcing and then continuing to pay $100,000 per year for design software is often unpalatable.

Fortunately for design companies, a variety of EDA tools are available that are not only comparable in price to the lower wage engineers, but also easier to install, learn, and maintain. Tools from more targeted EDA vendors often run on affordable and ubiquitous PC platforms that can be obtained and supported anywhere in the world. These more affordable EDA design tools are especially compelling in the case of analog or mixed analog-digital design.

Figure 1. Tanner EDA Analog/Mixed Signal Design Flow”

Analog Versus Digital: Why the Differences?

Why is the cost-reduction challenge different in analog design? Because analog design is so different from digital design:

• An analog algorithm can rarely be used for different circuit types through automation.
• The skill lies in choosing the right topology for the circuit, and this choice depends heavily on the application.
• Although the number of transistors is small, an analog design can be challenging because it requires a detailed understanding of the relationship between the transistors and the passive devices on the chip.
• Analog EDA tools, unlike digital tools, can only support what the design engineers do.

Since no high degree of automation is offered for analog design, effective analog design tools should not be expensive. Although analog tools do not automate the circuit design directly, there have been some attempts to speed up this custom design cycle.

Circuit simulation is a key aspect of analog design. Some EDA vendors advocate a full-chip simulation. Although simulating the entire chip is useful as a final sanity check, the majority of the analog engineer’s time is spent simulating key blocks in the design using a Spice circuit simulator, many of which are not expensive. For example, T-Spice Pro from Tanner EDA includes a Spice simulator, schematic editor, and a post-processing waveform viewer.

Affordable Approaches to Custom Automation

Some tools offer built-in support for custom automation. Mixed-signal designers often design similar circuits for different ICs or different cores for the same IC. An example is phase-locked loops that drive different digital blocks. Laying them out polygon by polygon for each new design is a tedious process. Fortunately, there are cost-efficient tools—such as Tanner’s L-Edit layout tool—that provide scripting and programming interfaces, which are as effective as those found in high-end mixed-signal tools.

The providers of high-end mixed-signal tools have made big claims of productivity improvements. Features such as schematic driven layout (SDL) and “on-the-fly” design-rule checks (DRCs) can dramatically improve designer efficiency. The SDL allows the designer to generate layout quickly from the schematic while continuously keeping track of connectivity of the circuit elements. Interactive DRCs typically contain only simplified design rules, but indicate violations of these rules to the designer as they are creating or editing the offending polygons.

A good interactive DRC improves design efficiency by catching 90 to 95 percent of design rule violations early on when they are easy to fix. However, there remains the need for a more comprehensive DRC at the full chip level that takes into account all design rules including connectivity-based and antenna rules.

Finding Cost-Effective Solutions

The design rule checkers offered by the largest EDA companies read design rules in proprietary formats defined by the vendors. The dominance of a few of these tools has resulted in de facto standards in rule file formats. Some EDA companies have taken advantage of the standardization of DRCs and built their own tools to natively support these standards. For example, Tanner HiPer Verify™ runs Calibre® and Dracula® DRC files unmodified.

Analog design cannot be performed as automatically by the design tools in the same way that digital design has been. The totally integrated analog design flow proposed by the largest EDA vendors may look good in theory, but it is difficult to see how their expense can be justified when tools from other EDA vendors can achieve the same results at one-tenth of the price.

How Important Is Support?

In selecting an EDA tool vendor, a design company should consider not only price and functionality, but also support. Some EDA companies are well known for supporting large accounts. Some of the alternative EDA companies are often much more responsive and many of these have honed their products over the years to need less support.

The major EDA companies have developed tool suites over the years from acquisitions. After the acquisition, typically the engineering staff that developed and supported these tools retires, leaving the vendors with less knowledgeable staff to support the tools. It may be hard for a customer to find someone who knows how their tool is supposed to work. In contrast, some other EDA companies develop their own tools in house and engineer them to work with other tools and to require little support. So, although some EDA companies have very responsive support departments, customers are better off not needing support at all.

Conclusion

In years past, the decision to buy EDA tools was easier. If a company could afford to buy the most expensive tools, it did. Now, the decision is more complex as illustrated in Figure 2. This is a three-dimensional decision matrix which highlights the applicability of high-priced tools: large die, digital and expensive engineer.

Figure 2

The growing analog content in chips demands a more engineer-intensive design methodology. This requirement drives offshoring, outsourcing, and the purchase of affordable EDA tools. Some of the small and medium-sized EDA vendors have been around for a long time, keeping the loyalty of their customers not only by affordable prices but also by ease of use, flexible licensing, low maintenance cost, superior customer support, and a growing range of functionality. Now, unless a company is working on a state-of-the-art, high-volume digital-only chip with high-priced engineers, EDA tools from a small or medium sized EDA company may be a good fit.

For product, pricing and licensing information please contact a Tanner representative via email at salesnw@tanner.com or +1-626-471-9701.