Connect the Dots: The ABCs of Clean Schematics

The production team is always excited when the first shipment of boards for a new electronic device comes back from the PCB manufacturer. Anticipation builds as the engineer connects the first set of components, puts everything together, and gets ready for that first test.

But when something goes wrong—a tiny pop, a sizzle, a puff of smoke, or nothing happens at all—the mood can turn from excitement to frustration. The engineer performs a postmortem and discovers a pinhole melted into the integrated circuit (IC), and then the culprit (a missing decoupling capacitor) led to a completely predictable voltage spike.

Where did the process go wrong? The engineer is certain that they put the capacitor in the right place. However, on closer examination, perhaps it is not close enough to the IC pad. Is it the fault of the PCB designer? Chances are that the designer will claim that they put the capacitor right where the schematic said it should be.

In a case like this, the fix is easy. The designer and the engineer get on the same page and produce a new design in 15 minutes. Unfortunately, the current batch of boards is now only useful as a set of coasters—delaying the project and potentially creating budget overruns.

This is a common issue for electronics manufacturers, and it is completely avoidable.

Good Schematics Are Good Communication
When engineers start to put together projects, the schematics are vital to good communication with the PCB designer. Theirs is a team effort. The schematic is where the engineer thinks through the project. However, by the time they hand it off to the designer, it needs to be a clean, comprehensible document that isn’t vague and doesn’t confuse. Most importantly, the engineer needs to communicate everything the PCB designer needs to design the right board for the project.

Best Practices Are There for a Reason
We all know that best practices exist, but real-world circumstances often lead to cutting corners. Saving time by ignoring best practices—like performing one last design check before submitting to the manufacturer—is just going to cost more time and money later. Even though it seems exhausting and repetitive, best practices involve starting at high-altitude block diagrams and then breaking each block into schematic sheets, checking flow and accuracy carefully, and then finally designing the board.

After that, a best practice has the engineer and designer picking over the design carefully, ensuring that it matches the specs—before it goes to the PCB manufacturer.

Designers Will Do What You Tell Them to Do
Engineers need to remember that designers don’t read minds; they read schematics. The engineer may understand implicitly the locations for all their bypass capacitors, but they can't rely on the designer's interpretation to properly place the elements. Instead, locate devices in roughly the manner of the final design to help the designer avoid bad interconnects, placement assumptions, or other errors.

It never hurts to provide the designer with explanatory notes about the elements. You will never hear a designer say that the engineer provided too much guidance for their work.

For example, utilize good naming conventions for connections or net names. Automated labels from design software are rarely helpful or intuitive. Create labels a human can understand.

Leverage Your Tools, But Don’t Use Them as a Crutch
Sometimes, engineers will give implicit connections using port symbols for the entire schematic. Unfortunately, this practice leaves no trail for the designer to follow. While the engineer may have saved a couple of minutes, the designer spends more time sorting out the nest of connections.

Let the software be on your side. It tracks and confirms those connections for a reason. This may feel like an obstacle for the engineer, but for the overall project, these tools are a lifeline.

The design rule check (DRC) is another example where the tool exists, but results may get ignored in the interest of saving some time. Too often, issues are ignored because they seem unimportant. However, over time these errors build up and create a confusing mess that may obscure errors that are truly important. One of your team's best practices should be generating a DRC report that reads no warnings and no violations.

More Recommendations for Clean Schematics
In addition to the broader best practices of fostering good communication and not relying too much on technology, the following are key methods that help ensure a clean schematic and a manufacturable, functional PCB design.

  • Design the schematic in the design program and label all connects with comprehensible net names—no auto-generated names
  • Lay out the schematic in a manner that clarifies locations
  • Label the schematic so that the next person can understand it
  • Create an environment where designers are comfortable asking for clarification if they are uncertain how to proceed
  • Use the DRC and address the warnings and violations it reports

Well-designed schematics will save time, money, and frustration both for your current project and future endeavors. If your schematic is nice to look at and easy to understand, your team can utilize blocks for other similar projects down the road. Teams that commit to good schematic practices win the long game.

Commit to Best Practices and Good Process
We all want to create great final products. Designers want to make great boards. Engineers want to make great schematics. To get there, we also need to think about making the work of the next person easier. When you commit to best practices, clear communication, and clean schematics, everyone benefits.

This column originally appeared in the October 2022 issue of Design007 Magazine.

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2022

Connect the Dots: The ABCs of Clean Schematics

10-19-2022

The production team is always excited when the first shipment of boards for a new electronic device comes back from the PCB manufacturer. Anticipation builds as the engineer connects the first set of components, puts everything together, and gets ready for that first test. But when something goes wrong—a tiny pop, a sizzle, a puff of smoke or nothing happens at all—the mood can turn from excitement to frustration. Where did the process go wrong? Here, Matt Stevenson provides several commonsense tips for avoiding these types of situations.

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Connect the Dots: Examining the Benefits of Laser Direct Imaging

09-22-2022

One of the most amazing advances in PCB manufacturing technology has been the advent and usage of laser direct imaging (LDI) technology. For PCB manufacturers, this technology has been a game changer, helping to reduce costs, speed production, and improve quality. Though the LDI revolution began more than 20 years ago and usage of film for image transfer has reduced by half in that time, there’s still room for more PCB manufacturers to invest in this powerful tool. As an image department team leader and ISO process owner, Trina Taylor has seen firsthand the benefits of laser direct imaging for both my team and our customers.

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Connect the Dots: Controlled Impedance—The Devil is in the (Math) Details

08-16-2022

Controlling impedance is critical to signal integrity and board performance in devices powering everything from high-speed digital applications to telecom and RF communication. It is common practice for designers to include impedance-related notes with their PCB designs and rely on the manufacturer to determine the proper trace parameters. This inherently passive methodology often leads to delay, cost overrun, and even batches of useless boards.

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Connect the Dots: Caution—Yield Ahead

08-11-2022

Manufacturing yield is a key measure of quality in PCB manufacturing. Measured as a percentage of good parts relative to the total produced, achieving 100% yield rates is extremely challenging for anything but the simplest PCB designs. Most PCB manufacturers produce less than a 95% yield, eating the cost of discards and re-designs. PCB manufacturers can take steps to improve yield rates. It is possible to achieve over 98% yield rate by addressing common manufacturing errors, improving safety and quality in tandem, and integrating a Lean approach to all processes.

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Connect the Dots: Bringing PCB Quoting Into the 21st Century

06-21-2022

Here we are in the 21st century, technology abounds across all sectors, and it continues to grow. Advances in wearable technology, vehicles with driver assistance features, and integrated smart home electronic devices continue to drive demand and innovation in the PCB industry. The product development teams tasked with taking these technologies from design into reality are often stuck using procedures from the last century.

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Connect the Dots: The Benefits of a Parts Library

06-02-2022

To be effective at PCB design and layout, individuals need to become proficient with the different tools of the trade. Parts libraries are among of the most important. PCB design and prototyping is a critical component of electronic product development. Being faster to market has always been a competitive advantage and a focus for electronics manufacturers. With persistent marketplace uncertainty and supply chain disruption creating delays, in-house PCB design offers a way to accelerate electronic product development projects.

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Connect the Dots: Leaning into Lean Manufacturing

04-26-2022

The worst part of the global COVID pandemic brought unpredictability and uncertainty to an otherwise stable PCB Industry. Like many in the board business, Sunstone faced increasing demand from essential businesses while also dealing with inconsistent employee availability and social distancing guidelines that slowed the manufacturing process. We knew immediately that even though the status quo had worked to this point, the situation was not temporary, and the operation would have to adapt.

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Connect the Dots: Six Key Considerations for Designers New to PCB Layout

03-31-2022

Demand continues to increase for boards used in consumer electronics, intelligent machines used in manufacturing, and smart devices for health services applications. Our industry needs more smart people designing PCBs to help drive artificial intelligence (AI) initiatives and power the Internet of Things (IoT), which is why we are welcoming new designers into the fold every day.

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Connect the Dots: The PCB Design Secret Sauce for RF Applications

02-24-2022

Design and manufacture of PCBs for radio frequency (RF) technology is a unique animal. RF had been considered a niche, thought of only in terms of television broadcasts, commercial airline phones, and military radar systems. Now, light industrial and consumer applications ranging from remote meter reading to home security systems are just the tip of the RF iceberg.

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Connect the Dots: Everything You Wanted to Know About Electromagnetic Interference

01-20-2022

EMI is another of those TLAs (three letter acronym) that the PCB industry is notorious for. You hear it all the time, referring to electromagnetic interference. The devices we create are, in the context of this conversation, bundles of boards, chips, and cables that produce and are affected by EMI. When current flows through wires, traces, or circuits, some of the energy is propagated through the air in the form of electromagnetic radiation. This also takes place within a closed design—creating disturbance voltages throughout the conductors in your device.

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2021

Connect the Dots: Best Practices for Solder Mask Application

12-16-2021

Today’s PCBs increasingly have to operate in challenging conditions. Whether it’s an iPad hot to the touch after several hours of gaming or a drone slicing through smoke and debris to monitor a wildfire, boards need protection from the elements. That’s where solder mask comes in. Solder mask coats your whole board (apart from the solder pads) so the PCB doesn’t react with the atmosphere and lose chemical properties through oxidation. It also prevents contamination from dust and debris that may settle on the board and create shorts. Solder mask prevents bridging between features during wave reflow assembly, limits external conductive influences and helps ward off voltage spikes.

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Connect the Dots: Diving Into the Chemical Processes of PCB Manufacturing

11-12-2021

I have always been fascinated with chemistry and chemical processes. My first degree was in chemistry and my first job out of college was in the PCB manufacturing shop in the analytical chemistry lab. During my initial tour I was so surprised with just how many chemical processes there were in PCB manufacturing. I discovered that some of the most critical elements of PCB manufacturing involve chemical processes. Chemicals clean the copper in preparation for the coating that prevents oxidation, and again to remove contaminants before solder resist application.

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Connect the Dots: Finding Value in Gerber Files

10-28-2021

Converting to Gerber is one way to perform a double check of your PCB design that can pre-answer questions from your manufacturing partner and pre-solve problems with the boards themselves.

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Connect the Dots: Designing PCBs for Electronic Hardware Products

09-23-2021

We asked an expert what factors designers should consider as they lay out their boards.

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Connect the Dots: The Split Planes Challenge

08-11-2021

Losing track of voltage in your PCB design can lead to explosive problems. Your CAM tool will not manage split planes for you.

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Connect the Dots: The Board Thickness Challenge

07-21-2021

Size constraints, functional requirements, and environmental factors can make selecting PCB thickness difficult. Here we will examine best practices for choosing board thickness that results in quality, highly functional PCBs.

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Connect the Dots: There is No ‘Final’ Frontier for PCB Design

06-10-2021

Our ongoing mission: To explore more manufacturable designs, to seek out higher-quality boards and enhanced functionality, to boldly design PCBs that no one has designed before.

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Connect the Dots: A Closer Look at Surface Finish

05-17-2021

The final surface finish of a PCB is an important consideration. This coating between your components and the bare board is applied to ensure solderability and protect any exposed copper circuitry. Selecting the right type of surface finish can be daunting, and for good reasons.

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Connect the Dots: The Power Behind the (PCB) Throne—Power Supply Design Tips

04-13-2021

Delivering the required power to each component on a PCB can be a complex challenge. Designers have to manage converting AC to DC while also delivering the correct voltage and current to each component. A well-designed PCB results when the designer takes power supply seriously—paying close attention to the effects that power delivery can have on surrounding components, such as through heat management or signal interference.

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Connect the Dots: IoT is Changing How We Design PCBs

03-11-2021

Demand growth is fueled by business as well as consumers, with pandemic-accelerated healthcare and industrial machinery applications leading the way. IoT devices of every stripe will continue to improve and add functionality while also becoming smaller, lighter, and faster.

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2020

This Month in Design007 Magazine: Connect the Dots—Is 2020 Really Coming to an End?

12-09-2020

As we approach the end of 2020, we are able to look back on one of the most challenging years that I have ever experienced. Throughout these trying times, Bob Tise and Matt Stevenson were consistent in their desire to share knowledge with everyone. Matt shares a synopsis of the topics they shared from the perspective of a PCB manufacturer.

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Connect the Dots: The New Recipe for Customer Service Success

11-11-2020

How are you holding up these days during the pandemic? Each of us is dealing with life struggles and changes differently. With this in mind, Matt Stevenson asks Al Secchi, global customer support and sales manager, what he has learned professionally from the pandemic and how to serve customers.

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Connect the Dots: Unraveling the Mysterious BGA Routing Mess

10-19-2020

A ball-grid-array (BGA) device can be a daunting component to route, especially in fine-pitch arrays featuring solder ball counts in the hundreds and pitch values as tight as 0.5 millimeters. Bob Tise and Matt Stevenson describe how you can take the mystery out of BGA routing and create a PCB design that can handle all those pesky narrow spaces.

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Connect the Dots: How to Know If a CAD Tool Is Right for You

09-21-2020

The tool that defines PCB designers is our CAD software, and many discover quickly that not all CAD tools are created equally. Bob Tise and Matt Stevenson answer the question, "How can designers find the right CAD tools to fit their particular methodology and needs?"

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Connect the Dots: The Nuts and Bolts of Electrical Testing

08-12-2020

In this column, Bob Tise and Matt Stevenson explore the world of electrical testing. They examine a variety of testing methods, what options to look for in a PCB manufacturer, and how to ensure that you're getting the best value out of the electrical test options available to you.

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Connect the Dots: Reassessing the Risk of Offshore PCB Manufacturing

07-15-2020

Offshore board production has long been considered an effective way to reduce the cost of producing electronic devices here at home, but those savings often demand a higher tolerance for delivery issues and come with lowered expectations for quality. Bob Tise and Matt Stevenson explain.

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Connect the Dots: The Power of Forward Thinking

06-06-2020

Innovation comes in many forms and from more places these days. Bob Tise and Matt Stevenson discuss how innovative electronic devices all contain PCBs, and share pro design tips for bringing new products to the market.

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Connect the Dots: Picking a Prototyping Strategy

05-29-2020

No matter how simple or complicated your electronic project, PCB prototyping is part of its journey from concept to reality. This process of turning the design into something physical can teach you a lot about what needs to be tweaked and improved before your PCB is ready for full production. Bob Tise and Matt Stevenson explain how before you can prototype, you have to design.

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Connect the Dots: Increased Focus on Health and Wellness Transforms the PCB Industry

04-04-2020

Our increased focus on health and wellness drives technology advancement for personal devices and those used in the delivery of healthcare. Bob Tise and Matt Stevenson explain how this trend also drives both PCB production innovation and a long-overdue update of the employer/employee relationship.

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Connect the Dots: The Seven-year Etch

03-16-2020

PCB etching seems like a simple task on the surface, but quite a few things can go wrong during this process. Adhering to best practice and continuous improvement is a must to help avoid issues with your finished board. Bob Tise and Matt Stevenson share their design tips for a better etching process.

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2019

Connect the Dots: A Penny for Your Thoughts on Copper

11-19-2019

You're probably thinking: “Bob can’t possibly write an entire article dedicated to the use of copper in PCBs.” To that, Bob says, “Hold my beer.”

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Connect the Dots: Build Quality Into Your Boards and Processes

11-06-2019

To the procurement clerk, a PCB may seem like it is just a line item on a bill of materials (BOM) or parts list during the production of an electronic device. At Sunstone, we know differently. The PCB is the building block for all of the components and parts in your electrical project.

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Connect the Dots: A Proactive Approach to Controlled Impedance

10-09-2019

You can save time, money, and effort if you are aware of the impedance math when you sit down to design your board. Gain this awareness by using a good impedance calculator, and you can build the right tolerances into your design. Impedance testing becomes a double-check of your work instead of the tool you rely on to tell you if your documentation is correct. Documenting impedance requirements properly is more onerous than most people realize. Though it seems simple, PCB documentation is a details game that often leaves knowledge gaps for your manufacturer.

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Connect the Dots: Managing Global Supply Chain Uncertainty

09-03-2019

We are well into the second year of tariff-centric trade policy, and one thing appears certain—uncertainty is here to stay. Though most of the media focus has been on cars and steel or consumer prices and corporate profits, the enduring challenge for both the electronics and PCB industries has been maintaining reliable global supply chains.

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Connect the Dots: Five Best Practices to Ensure Manufacturability

08-01-2019

When you send your design for manufacturing, your partner does not know what type of device the board will be part of nor the conditions in which it will have to perform. It’s common for harsh environments or exposure to mess up a board’s performance. If you call out materials that will not tolerate the end-product’s operating environment, bad things can happen—such as a smoking board, for example. Be sure your board can tolerate thermal stress or solder joints risk breaking and damaging components.

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Connect the Dots: The Future of PCB Manufacturing Doesn't Belong to Robots, but to the Users

07-09-2019

Is the world ready for the consequences of rapid automation? Will the use of robots displace entire categories of workers? Can artificial intelligence really “think”? How will manufacturing, including PCB manufacturing, be affected by all of these smart robots? These questions actually come from a pamphlet published in 1955: "The Age of Automation: Its Effects on Human Welfare."

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Connect the Dots: Accurate Gerber Files Are Mission-Critical for Smooth PCB Manufacturing

05-30-2019

Gerber files can reveal design issues ahead of the quote process and ensure your manufacturer has everything needed to produce your boards correctly. After consulting with Engineering Support Specialist Eric Haugen, we explored some best practices for making sure that Gerber files are accurate.

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Connect the Dots: Preparing for Tomorrow’s Technology Today

05-16-2019

At a recent Sunstone Circuits planning summit, Matt Stevenson, VP of sales and marketing, and Bob Tise had a wide-ranging discussion about emerging technologies and how they will impact PCB manufacturing. The following is an abridged transcript of this conversation.

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Connect the Dots: MakeHarvard 2019: Bigger and Better!

04-09-2019

Sunstone Circuits was eager to return to MakeHarvard as a sponsor and creator of a competition category this year, also serving as both mentors and competition judges. If you were there, you saw us—we were hard to miss in our bright orange vests. As mentors, we were out and about helping students and answering questions.

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Connect the Dots: Exploding PCBs: Don’t Lose Track of Voltage in Your Design

04-01-2019

Managing split planes? Your CAM tool will not do it for you. We see this almost every day—not exploding PCBs, which pretty rare—but rather problems created by having more than one voltage on a power plane layer. From where we sit, this is one of the more insidious and costly challenges facing PCB designers.

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2018

Connect the Dots: Six Tips to Ensure Parts Fit on Your Board

12-12-2018

One of the most frustrating mismatches with alternative through-hole parts occurs when the land pattern matches, but the pin size is off. If hole sizes are too tight, pins may not fit through the holes, or if they do go into the holes, they may not solder well. Solder will need to flow through the gap between the pin and the hole barrel. If there is not enough space to allow enough solder mass to flow through the hole, the circuit board will absorb heat from the molten solder and cause the solder to solidify partway up the hole. This is called a cold solder joint and can result in a premature failure of your circuit.

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Connect the Dots: New Landing Design to Reduce Thermal Pad Failure

11-16-2018

You’ve finally finished your design. All the traces are correct and the IC landings are to the manufacturer’s specifications. A short run of test boards performs perfectly. For best results, you select a reputable domestic board house for production and a quality assembly shop to do the soldering. When the finished boards arrive, everything looks great. You’re in high spirits and congratulate yourself on a job well done. Then the reports start coming in.

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