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Rob Boguski

Or even mildly irritated. So watch those catchphrases.

As we move into 2021, I resolve to renew my approach to doing business, call things as they really are, and exile all my peeves into permanent residence, where they belong, in their appropriate circle of Hell, apropos Dante Alighieri.  

That’s right: we’re talking Inferno.

Flames have consequences.

Nine circles. Nine gripes. All therapy.  

In ascending order of severity.

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Read more: Hell Hath No Fury Like A Test Engineer Scorned

Robert Boguski

Can a head in the sand avoid a corpse in the water?

“We’re line down.”

Sorry to hear that. (Not really, but fake empathy makes them feel better.) They got the job as the low bidder. You reap what you sow.

“We’ve been building this product for five years. That’s 22,846 units manufactured successfully and counting.”

Congratulations. You just confirmed the adage that one “oh s--t” equals one million “attaboys.”

“Not a single electrocuted hot-tubber in that time.”

How reassuring. It is of such integral services as these that our gross national product is composed.

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Terry Jernberg

With many disciplines contributing, who will manage the process?

As technology trends toward smaller, faster, cheaper, the challenges around good PDN design get more difficult. With multiple requirements needed from many disciplines, the PDN’s demands will only increase and become harder to maintain.

Over the past few months, we have discussed elements essential to power delivery and PDN requirements. Now that we have a better understanding of this, it’s time to explore what is needed to create the ideal PDN product, and who is best equipped to bring together all the elements of the PDN.

What is a good PDN design, and how do you achieve it? Power-related design objectives tend to be similar in nature for all PCBs: to provide sufficient current at a stable voltage to each device. What does vary widely is complexity, however. Said objectives can range from simple single-supply, powering a solid power plane, to a multi-source, hot-swappable, self-monitoring, thermally sensitive, complex design that accounts for most components and a large amount of copper on the PCB. Simply put, good PDN design delivers power adequately and reliably.

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Read more: The Case of the Missing PDN Owner

Terry Jernberg

Understanding cap differences and modeling will help identify loop inductance issues early.

We’ve written for months about how to control power delivery. While we have learned the effects of layout on the PDN, we haven’t yet focused on the other major influencing factor: the decoupling capacitor.

These simple, 2-pin devices perform two main tasks: resist a change in voltage across their pins and accumulate and store “charge” that can be delivered from those pins to maintain that voltage. In the world of digital design, this “decoupling” function is huge and is arguably why we do power integrity (PI) simulation in the first place. The power demands of a product’s components are largely defined by its features and performance requirements, which determine supply sizes. Between those lies the power delivery network (PDN), a subject we’ve intensely studied. Composed almost entirely from capacitors and the copper that connects it all together, the success or failure of a PDN is often determined in layout. In previous articles, we’ve written about “loop inductance” and how it impacts the capacitors’ ability to do their job. A solid understanding of cap differences and modeling will help identify loop inductance issues early to ensure a successful PDN.

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Read more: PDN Effectiveness: The Devil’s in the Decap Details

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