By Ron Collett

The increase in semiconductor design complexity never slows. This reality always reinforces itself when I look at the agenda of a given week’s technology event. This week’s headliner is ARM Techcon3 in Santa Clara.

Here’s a sampling of the presentations:

• “How Software and Hardware Can Cooperate To Manage Power Consumption in ARM-based Systems”
• “Fireside Chat: Enabling Internet Eveywhere and Advancing Next-Generation Designs”
• “Energy Efficient Design at 65nm – What Really Works!”

And the list goes on—challenging design issues at complex technology nodes everywhere you look. It’s little wonder then that most semiconductor design projects slip schedule (see chart).

Old habits in a mature industry die hard. Engineers have built products in more or less the same way for 40 years, and they’ve had tremendous market success. So why change? Engineering intuition always seems to work, and a bottom-up approach to project staffing is the way we’ve always done things. No reason to change, right?

Wrong.

Projects slip for a number of reasons:

• We’re human. Who can predict when or if a spec change might occur or the flu takes out a few key engineers for a week?
• We often lack the context to make fact-based decisions for dizzingly complex designs. For example, if you’ve spread a design over three locations in different time zones, using a newly-acquired team designing to a new process, you’re trying to extrapolate the effect of those factors based on your experience. But you probably have never experienced those factors before because each design is different.
• Projects are late often because they are under-scoped. The schedule for the new project is based largely on the post-mortem of the last project, with the conclusion that none of the things that went wrong last time will be allowed to go wrong this time (and no other major new challenges will be allowed to creep in!).

Typical bottom-up reactions to managing such complexity tend to fall into two categories:

• Boost staff to hit schedule. This generally creates either a low-productivity, low-throughput situation or a high-throughput, low-productivity environment. Teams might hit schedule but will blow out the budget.
• Leverage a small, skilled team of engineers and drive it hard. This can marshal costs and improve decision-making, but a small team can produce only so much in a given period of time, even if it’s highly productive. Too much pressure to hit an unrealistic schedule also kills morale.

Sharp engineering managers can achieve best in class and cut or eliminate schedule slip by adopting a top-down approach that complements their traditional bottom-up planning. The top-down methodology uses:

• Quantified estimates of the chip’s complexity
• The team’s productivity
• A model of the rate at which effort will be expended on the project.

With the proper infrastructure in place, schedule estimates can be generated within just a few hours. At this point you can benchmark against your own experience or against the industry’s experience and make fact-based what-if tradeoffs to boost your schedule predictability and design ROI.

More than 80 percent of semiconductor projects slip schedule. But we can change this reality. You wouldn’t expect this from your foundry, would you? Your foundry partner gives you a precise estimate of yield on your chip based on its models and its vast experiences with similar projects. You should expect the same predictability from your product-development organization.

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