What is Your Supply Chain Telling You about Packages?

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Have you purchased any electronics components lately? Have you tried and failed to do so lately? Allocation is the word of the day and substitutions are your friend.

Many, many parts are in short supply, or unavailable with extraordinarily long lead times. Sure, that happens every now and then in this industry. It’s a periodic nuisance, but what should you do for the long term? We’re are getting some interesting stories from component suppliers that might help. 

What we’re hearing is that many passive manufacturers will be trying to move their customers to smaller sizes. They want to consolidate on as few packages as is possible. That means we may be seeing the end of 1206, 0805, and maybe even 0603 form factors for many passive values.

It kind of makes sense. Right now, there might be several dozen different varieties of 0.1uF, 16V capacitor. Does the industry need that? And if there isn’t enough fab capacity to make all of the variations, why not consolidate and run more of fewer variations? It won’t surprise me if we start seeing fewer voltage ranges as well. In most cases, a 16V part will be just fine if you’re calling for a 6V or 10V part.

The chip industry has been doing this for a while. Many of the newer components just come in BGA or QFN packages. Fewer and few leading edge parts come in large through-hole or SOIC packages.

Consider using smaller components, like standardizing on 0402 parts. I know it can be a pain to use smaller parts, but any potential for future proofing your design now can prevent delays or otherwise unnecessary redesign cycles. You might just be able shrink your board size and save some money on the board fab too.

Keep approved substitutions close by, and look for newer chips that are more likely to stay in production. For microcontrollers, pick parts that have multiple memory capacity or speed range variants all in the same package.

This looks to be a pretty extreme allocation cycle, and I have a feeling that the industry will be different when we come out of it.

Duane Benson
Which is worse
Being the missing link or the weakest link?

 

A Question on Schematic Style

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Just a quick question here…

I’m placing the components for my TinyFPGA based stepper motor controller board (see the prior articles here first, here next, and here last). Specifically, I’m finding places for all of the capacitors. That’s where the question of schematic style comes in. 

When I first started using CAD software, sometime shortly before the stegosaurus roamed the land, I would position component symbols on the schematic near the chips they belonged with. Doing so made it easy, come layout time, to remember which capacitors go where.

Since then, though — and I don’t remember when I started this — I’ve started following the practice of grouping capacitors on the schematic, as I’ve done on this sheet to the right. All of the capacitors are up at the top, shown connected to V+ and ground rails.

That’s not a problem when they’re all 0.1uf bypass capacitors and each chip just takes one. However, with higher speed and more complex chips, multiple bypass caps or different values are often required on each chip.

Now, when I go to layout, I need to go find my component data sheets again (they really should never be very far away) and re-figure out what combinations of bypass capacitors go to which pins on what chips.

I like the cleaner schematic that results from grouping bypass caps, but it’s adds pain and a bit of opportunity for error during layout.

What style do you use and why? Am I an idiot for doing it this way? Wait. Don’t answer that last question.

Duane Benson
Six of one and 12 × 5 × 10-1 of another

Does Solder Paste’s “Five Ball Rule” Remain Valid in SMT Today?

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Folks,

My good friends, Phil Zarrow and Jim Hall, in their audio series “Board Talk,” were recently asked about the “Five Ball Rule”. In the comments section for this session, one listener asked if this rule, created in the 1990s, was still valid. After all, the 1990s was the era of 0603 and 0402 passives; 01005 and even 008004 passives have arrived.

First, let’s consider what a “rule” is verses a “law.” As an example of a law, consider Newton’s Laws of Motion. At everyday speeds, these laws are shown to be accurate to within our capability to measure. As we will recall from Physics 101, these laws were superseded by Einstein’s Theory of Relativity, at speeds close to those of the speed of light. However, in our everyday world, Newton’s Laws are well … laws. They are, for practical purposes, exact.

What is a “rule” then? A rule is an expression that approximately fits some empirical data or the experience of experts. Moore’s Law is actually a rule, as it is not precise. The doubling of transistor density has varied from every 18 months to every two years. That’s why I call it a rule, a very useful rule indeed!

The “Five Ball Rule” is clearly a rule. It was likely developed a generation ago by some of the first SMT pioneers. It may be backed up by experiment, but I think it was likely more a consensus of SMT industry authorities from the 1980s and 1990s.

What is the “Five Ball Rule?” It states that the solder paste’s largest solder particle diameter should be such that at least five of these particle diameters would span the width of a rectangular stencil aperture (Figure 1).

Figure 1. The Five Ball Rule

 

 

 

 

 

 

 

When this rule was developed, stencil apertures were much coarser than today, and the finest solder powder was a Type 3, with Type 4 on the horizon. While it is true that stencil aperture widths are much finer today, solder pastes of Type 4.5, 5, and even 6 are now in use.

The particle sizes of different “Type” solder pastes are shown in Figure 2. Note that, for Type 4 powder, 80% by weight of the particle diameters are between 20 and 38 microns. 38 microns is considered the “largest particle.” So, from Figure 2, for Type 5 powder, the “largest particle” is 25 microns. For the sake of the Five Ball Rule, the “largest particle,” for each powder type are those shown in Figure 2.

Figure 2. Solder Powder Sizes.

 

 

 

 

 

 

 

 

 

So, is the Five Ball Rule still valid? It would be hard to argue that it is not. Hundreds of experiments have been performed using the Five Ball Rule, combined with the aperture ratio being >1.5 for rectangular apertures or the area ratio being > 0.66 for square or circular apertures, with successful results.

StencilCoach software now includes the newer (finer) solder powder sizes to 1) tell the user the fineness of solder paste powder for the Five Ball Rule, as well as 2) help with calculating aperture or area ratio. By the way, some have suggested that, for a square or circular aperture, an “Eight Ball Rule” is more appropriate. So, StencilCoach uses the Eight Ball Rule for such apertures.

Cheers,

Dr. Ron

 

PCB Chat: Are Designers Lazy, and is Automation All-Important?

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“Content is the most important aspect of the design world right now,” says Manny Marcano, president of EMA Design Automation. Over the past nearly three decades, he has grown EMA into the leading Cadence Channel Partner as the exclusive distributor of OrCAD in North America. EMA has also developed a series of its own software products for library management, component supply chain data, and conducts training.

Manny talks about the role of automation and whether designers are keeping up with their profession this week as my guest on PCB Chat.

In Acquisition Mode, Foxconn is Turning Up the Heat

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OEMs, beware: Foxconn is coming for you.

No, not just to buy your components, build your boards and run your logistics. Foxconn is coming for your data, your markets, and your customers.

We’ve been sounding the alarm about this for years. It’s not healthy for your primary supplier to be bigger than the nearly the entire rest of the market. Foxconn, pushing $150 billion in revenues, is as large as the next five EMS/ODMs combined, and more or less as large as numbers 7 through 500.

The 2016 buyout of Sharp could be chalked up to a desire by Foxconn to nab a key technology and supplier to Apple, it’s top customer. The just-announced deal for Belkin, however, coupled with its foray into developing 5G computing and cloud platforms,, suggest a drive to higher margin, branded products. Foxconn’s revenue is larger than almost everyone of its customers, and a new plan to issue $50 billion worth of stock could give it the capital it needs to go on a massive acquisition spree.

OEMs, beware.

In China, A Bet on Tariffs

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Several news stories are breaking today about President Trump’s anticipated tariffs on scores of goods from China. On the list of items that will see new import duties is consumer electronics.

The effects of this move have the potential to go far beyond the administration’s stifling of a series of high-profile acquisition attempts, including Singapore-based Broadcom’s attempted not-so-friendly takeover of Qualcomm, or that of a Chinese investment firm’s deal for Lattice Semiconductor. One wonders, if the TTM-Meadville deal were in play today, what the ruling from the feds would have been.

China has successfully reached its goal of the “world’s factory,” but is it good for the US — or the world, for that matter — to have so much critical manufacturing concentrated in one place? I would argue no. Foreign companies get a raw deal trying to access the China market. The rules are set up to favor domestic companies, the government’s reach extends into all levels of private businesses, and the judicial system is weak, at best. As we have noted before, in China, “copyright” means “the right to copy.”

The US is the only economic body, except perhaps the European Union, capable of forcing China’s hand. China will not change on its own.

It would take a better fortune teller than me to predict how this will play out. On principle, some critics are primed to dismiss the administration’s move. But governments interfere in economic systems all the time. The entire US import system is one giant hurdle. So is Europe’s. It says here the risk is worth taking.

 

Talking Government Relations with IPC

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In my latest podcast, I speak with John Mitchell, president and CEO of IPC, and Chris Mitchell, IPC vice president of global government relations. They discuss the trade organization’s key government programs and initiatives, its annual member lobbying event coming up in May, and the importance of lobbying by member companies. Listen in at upmg.podbean.com.

Use an SMT Pre-Test Before Presenting a Soldering Workshop

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Folks,

Let’s see how Patty is doing, it’s been a very, very long time …

Even though Patty and her husband Rob both worked at Ivy University, they seldom drove in together. It was just too difficult to organize their schedules so that it would work out. So, as Patty was driving in to Ivy U, she was listening to the last chapter of Ron Chernow’s biography of U. S. Grant. Her timing was excellent, since she, Rob, Pete, and the Professor were having their monthly book club meeting. Rob, Pete, and the Professor were always recommending books about World War II or the Civil War. Because of this trait, she groaned every time it was the three “boys” turn to suggest the next book. But, she had to admit that she always enjoyed the books much more than she thought she would. She especially liked a book Rob discovered, called A Simple Solder. Patty found this true story, about a young boy in the German army in World War II and how he survived to tell the tale, fascinating. She would never tell Rob, but she read it three times.

When it was Patty’s turn she made sure to avoid those military topics. Recently, she proposed another one of Chernow’s biographies on John D. Rockefeller. She also suggested  iGen: Why Today’s Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy–and Completely Unprepared for Adulthood–and What That Means for the Rest of Us by Jean M. Twenge. This book convinced her and Rob to dramatically limit “screen time” for their 9-year-old twin boys.

As she approached her parking spot, the audio book on Grant finished. She was a bit sad, as she had enjoyed this book as much as any. Patty had the impression, from her high school history classes, that Grant led the Union to victory over Robert E. Lee only because he had superior forces, weapons, and supplies. Chernow’s book clearly dispelled that notion. Grant was a great general. In addition, he was an effective and honorable president, if a little too naïve and trusting to avoid numerous scandals among his subordinates.

In a few moments, they met in The Professor’s large office. After they finished their book club chat about Grant’s biography. Patty had a favor to ask.

“Mike Madigan asked me to give a three-day workshop on SMT 101 at one of ACME’s recently acquired facilities. He said he felt the technicians and engineers weren’t very knowledgeable. I’m having trouble deciding at what level to aim the workshop,” Patty began.

“You mean like for beginners, intermediate, or expert?” Pete asked.

“Yes,” Patty responded.

“Well, you should develop it in a logical sense, starting with what soldering is, discuss flux and solder paste, then stencil printing, component placement, reflow, test, etc,” Rob added.

“I agree with Rob’s outline, but you need to find out the current knowledge level of the students,” The Professor suggested.

“I once gave an eight-hour seminar on SMT Defect Modes and How to Fix Them. The workshop was advertised as for SMT engineers and technicians with intermediate experience. At the end of the workshop a person raised his hand and asked an unsettling question,” The Professor continued.

“And the question was?” Pete teased.

“Professor, you have used the word ‘SAC’ many times, what does ‘SAC’ stand for?” The Professor responded.

In unison, Patty, Rob and Pete groaned.

“That’s my concern! At which level do I aim the workshop? If I shoot too low, it might insult people. If I shoot to high it might go over their heads,” Patty responded.

“OK! So, how do I structure the workshop, not knowing the skill level of the students?” Patty asked a little frustrated.

“How about a pre-test?” The Professor suggested.

“OK! But how many questions?” Rob asked.

“It needs to be short, yet comprehensive,” The Professor suggested.

“Seems like a contradiction,” Pete grumbled.

“I think The Professor is right. Look at it this way, let’s say you want to assess if your 14 year old nephew knows much about The Civil War. Ask him three or at most five questions and you can determine if he does,” Patty suggested.

“How about some examples?” Pete asked a bit dubious.

“I’m getting it. How about when was the war fought, who was Robert E. Lee, what is the significance of Appomattox Court House?” Rob chimed in.

“OK, I see you point. If you know two or all three, you probably know a lot, one or less and you don’t know much,” Pete responded.

Patty then suggested, “OK let’s develop a list of ten SMT Pre-Test questions.”

After about 20 minutes of back and forth, our team of four converged on these 10 questions.

SMT Pre-Test

  1. What does the letter “S” in SAC stand for?
  2. How much silver is in SAC 305?
  3. PWBs are coming off of the final component placement machine at a rate of one every 20 seconds. The PWBs are 20cm long and should be placed with at least 4cm of space between them. What must the reflow oven belt speed be to accommodate this cycle time?
  4. The starting temperature is 25°C. It needs to be 145°C in one minute. What heating rate is needed, in °C/s, to achieve this temperature?
  5. About how much does silver cost per troy oz.? (+/- 30%)
  6. Which is a closest to typical stencil thickness?
    • 5 microns
    • 20 mils
    • 5 mils
    • 20 microns
  7. Which is closest to a typical lead spacing for a plastic quad flat pack (PQFP?)
    • 0.1mm
    • 0.1 mil
    • 0.4mm
    • 0.4 mils
  8. Which has finer solder particles, a Type 3 or 4 solder paste?
  9. What does OSP stand for?
  10. Place an arrow at the eutectic point of the tin-lead phase diagram below.

Would you like to try the pre-test? The answers have to be what you know without looking anything up. Send me your answers at [email protected]. The first person to get 100% will get an item of memorabilia signed by Patty, Rob, Pete, and The Professor.

Cheers,

Dr. Ron

Latest Podcasts Look at AS9100D, EMS Innovation

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A couple new podcasts to call your attention to.

In one, I speak with my longtime friend Randall Sherman, the EMS/ODM analyst and founder of New Venture Research, on recent developments in the market and how EMS companies are leading innovation by building intelligence into production systems.

In the second, I discuss the ongoing issues faced by the supply chain, and especially fabricators, in the wake of AS9100D.

The podcasts can be found at https://upmg.podbean.com.

 

The Bourse Identity

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Foxconn’s prospectus to issue a public offering to raise money for its nascent foray in to cloud computing is less revealing for what it proposes than where the offering will take place.

Rather than leverage its newfound admiration in the US (or at least, in a couple pf offices in Washington) by accessing the Nasdaq or NYSE, instead Foxconn is opting for a far less prominent bourse: the Shanghai Exchange.

The reasons are obvious: The Shanghai bourse lacks the capital controls and oversight of the world’s dominant financial exchanges. A company, even one as large as Foxconn, can get away with a lot more, since reporting requirements and level of scrutiny are so less rigorous than in New York or Munich or London. Foxconn’s financial picture is opaque: even reporting on its revenues and profits remains an uncertain undertaking. Staying offshore makes that possible.

Finally, Shanghai is a Chinese exchange and Foxconn is a Chinese company. (Yes, I know it’s based in Taiwan. But look where the bulk of its facilities, workers, investment and attention is. And keep in mind that for many Taiwanese, China is still the motherland.) This latest move underscores that fact.