Further integration means more mixed-signal circuitry will need to be integrated onto one chip over the next few years. By 2006, as many as 70% of all the system-on-chip (SoCs) produced will need to have some form of mixed-signal content, ranging from phase-locked loops through to complete mixed-signal subsystems such as audio codecs and communications front-ends.

The big EDA players have not missed this. They have promised to integrate their offerings, to bring digital and analog designers together under the umbrella of a unified design tool-suite. What this approach misses is the fact that there is a high degree of craft in analog and mixed-signal design. Generally, the key to a successful analog design is the choice of the right topology for a circuit, and that takes experience. You will not get analog design tools to design a circuit the way highly automated, and consequently expensive, digital tools do. So, what will you be paying for with these promised tools?

The unified databases proposed by the big EDA players sometimes may have some benefits, but they restrict users' ability to take advantage of lower cost, easier-to-use tools for analog and mixed signal layout, for example. And a unified database is just not necessary when you have the layout information in the one format the EDA industry accepts wholeheartedly: GDS II. So there is no need to tie yourself to a database that will lock you in.

Other high-end features, such as on-the-fly design-rule checks, sound promising. But they may prove lacking when you consider the fact that design rules are becoming more complex and need to take into account global chip-design issues.

What about support for the one piece of automation that works in analog design: device and layout generation? There we can agree with the high-end vendors. But more cost-effective tools have those features, with highly effective object-oriented programming interfaces that let experienced analog designers build functions to automatically generate transistor fingers and other complex shapes quickly and easily.

So, if you think your only choice is to pay high-end prices for mixed-signal design think again. Cost-effective analog tools work very well with advanced digital tools. They will let you get better payback on your next SoC project and integrate into your design flow at just the right points.

John Tanner co-founded Stac Electronics and, in 1988, spun out Tanner Research, Inc. to focus on electronic design automation (EDA) software and other aspects of advanced micro-electronic design. Over the past 15 years Dr. Tanner has guided Tanner Research through rapid growth, and remains chairman and president.