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In this article, we’ll discuss the key design features to implement, and steps to take prior to fabrication that will help prevent some common DFM problems. I’ll also provide examples of where I commonly see these PCB DFM problems in signal integrity circuits.
If you’re working with a high-speed digital component, there are some simple power integrity rules that should be followed. However, there is one quantity that is sometimes ignored when building a PDN impedance simulation: the spreading inductance of your plane pair. Here are some points designers should know about the spreading inductance of a plane pair.
In this article, I’ll present some design basics that every new designer should follow to help ensure their design process is successful. Some of these points may challenge the conventional view of how circuit boards are constructed, but they are intended to help balance low noise signaling, manufacturability, and ease of solving a layout.
The primary goal of your traces is to carry signals throughout your board without losses. To do this properly, you must familiarize yourself with the requirements for signals on the printed circuit board and how to optimize the topology of the board in terms of signal integrity. We will analyze the most popular routing cases applicable for using the Gloss and Retrace tools in Altium Designer to optimize your signal integrity.
High voltage PCBs are subject to certain safety and reliability concerns that you won’t find in most other boards. If your fabrication house specializes in high voltage PCBs and keeps materials in stock, they can likely recommend a material set, as well as a standard stackup you might use for certain voltage ranges and frequencies. If you need to choose your own materials, follow the tips below to help you narrow down to the right material set.
There are some guidelines I see many designers implement as a standard practice, often without thinking about it. Some of these practices are misunderstood or implemented without best practices. Others are implemented without thinking about the potential problems. One of these is the use of tented vias, which is sometimes implemented in a PCB layout by default. Is this always the right practice?
The idea of a purely capacitive load is something of a fallacy. Yes, capacitors exist, but all capacitors are non-ideal, and it is this deviation from a theoretical capacitance that determines how to impedance match a load that exhibits capacitive behavior. Let’s take a look at this important aspect of interconnect design and see what it really means to terminate a capacitive load.
There are all sorts of version control systems out there that people have been using with their PCB design software. As discussed in Why Use a Version Control System, we looked at different options ranging for local hard drive storage to sophisticated online revisioning systems. In this article we will be reviewing the differences between a standard VCS and Altium 365.
Version Control Systems (VCS) have been around for many decades within the software world but can be surprisingly new to some folks in the electronics design industry. This article will cover what a VCS is, what it does, and why you should be using one for your PCB design projects.
Designers often conflate leftover annular ring and pad sizes - they need to place a sufficiently large pad size on the surface layer to ensure that the annular ring that is leftover during fabrication will be large enough. As long as the annular ring is sufficiently large, the drill hit will not be considered defective and the board will have passed inspection. In this article, I'll discuss the limits on IPC-6012 Class 3 annular rings as these are a standard fabrication requirement for high-reliability rigid PCBs.
Sending a board out for fabrication is an exciting and nerve-wracking moment. Why not just give your fabricator your design files and let them figure it out? There are a few reasons for this, but it means the responsibility comes back to you as the designer to produce manufacturing files and documentation for your PCB. It’s actually quite simple if you have the right design tools. We’ll look at how you can do this inside your PCB layout and how this will help you quickly generate data for your manufacturer.
When some designers start talking materials, they probably default to FR4 laminates. The reality is there are many FR4 materials, each with relatively similar structure and a range of material property values. Designs on FR4 are quite different from those encountered at the low GHz range and mmWave frequencies. So what exactly changes at high frequencies, and what makes these materials different? To see just what makes a specific laminate useful as an RF PCB material, take a look at our guide below.
In today’s fast-paced world where iterations of electronics are spun at lightning speeds, we often forget one of the most critical aspects of development: testing. Even if we have that fancy test team, are we really able to utilize them for every modification, every small and insignificant change that we make to our prototypes? In this article, we will review a very low cost, yet highly effective and quite exhaustive test system that will get you that bang for your buck that you’ve been looking for.
If you’ve ever looked at the BOM for a reference design or an open-source project, you may have seen a comment in some of the entries in your BOM. This comment is either “DNP” or “DNI”. If you think about it, every component placed in the PCB requires some level of placement and routing effort, which takes time and money if you’re working for a client. This begs the question, why would anyone design a board with components they don’t plan to include in the final assembly?
When it’s time to share your design data with your manufacturer, it’s like taking a leap of faith. Sending off a complete documentation package might seem as easy as placing your fab files in a zip folder, but there are better ways to ensure your manufacturer understands your project and has access to all your design data. For Altium Designer users, there are multiple options for creating and packaging release data into a complete package for your manufacturers.
If you’re designing a circuit board to be powered by anything except a bench-top regulated power supply, you’ll need to select a power regulator to place on your board. Just like any other component, your regulator has stated operating specs you’ll see in a product summary, and it has more detailed specs you’ll find in a datasheet. The fine details in your datasheets are easy to overlook, but they are the major factors that determine how your component will interact with the rest of your system.
It would be nice if the power that came from the wall was truly noise-free. Unfortunately, this is not the case, and although a power system can appear to output a clean sine wave, zooming into an oscilloscope trace or using an FFT will tell you a different story. When you take "dirty" power, put it through rectification, and then pass it through a switching regulator, you introduce additional noise into the system that further degrades power quality. If you’re a power supply or power systems designer, then you know the value of supplying your devices with clean, noise-free power.
If you’re an electronics designer or you’re just beginning your career as an engineer, the PCB stackup is probably one of the last things you’ll think about. Simple items like PCB copper thickness and board thickness can get pushed to the back burner, but you’ll need to think about these two points for many applications as not every board will be fabricated on a standard 1.57 mm two-layer PCB
I often get questions from designers asking about things like signal integrity and power integrity, and this most recent question forced me to think about some basic routing practices near planes and copper pour. "Is it okay to route signal traces on the same layer as power planes? I’ve seen some stackup guidelines that suggest this is fine, but no one provides solid advice." Once again, we have a great example of a long-standing design guideline without enough context.
Electronics schematics form the foundation of your design data, and the rest of your design documents will build off of your schematic. If you’ve ever worked through a design and made changes to the schematic, then you’re probably aware of the synchronization you need to maintain with the PCB layout. At the center of it all is an important set of data about your components: your schematic netlist. What’s important for designers is to know how the netlist defines connections between different components and schematics in a large project.
There are plenty of PCB manufacturing services you can find online, and they can all start to blend together. If you’re searching for a new service provider, it can be hard to compare all of them and find the best manufacturer that meets your needs. While experienced designers can spot bogus manufacturers from afar, there is always a temptation to go with the lowest priced, supposedly fastest overseas company you can find. However, there is a lot more that should go into choosing a PCB manufacturing service than just price.
Pi Filters are a type of passive filter that gets its name from the arrangement of the three constituent components in the shape of the Greek letter Pi (π). Pi filters can be designed as either low pass or high pass filters, depending on the components used. The low-pass filter used for power supply filtering is formed from an inductor in series between the input and output with two capacitors, one across the input and the other across the output. Keep reading to learn more about their application in the PCB Design.
The first question that should come up when selecting materials and planning a stackup is: what materials are needed and how many layers should be used? Assuming you’ve determined you need a low-loss laminate and you’ve determined your required layer count, it’s time to consider whether you should use a hybrid stackup. There are a few broad situations where you could consider using a hybrid stackup with low-loss laminates in your PCB
Batteries offer a great power source for electrical devices that need to be mobile or located somewhere where connection to a mains electricity supply or other power source is impossible. The biggest problem with battery power is the expectation of users that the device will operate for significant periods with the need for recharging or replacing the batteries. This demand is placing the onus on the designer to improve efficiency and reduce power demand to meet this need.
A number of us on this blog and in other publications often bring up the concept of target impedance when discussing power integrity in high-speed designs. Some designs will be simple enough that you can take a “set it and forget it” approach to design a functional prototype. For more advanced designs, or if you’re fine-tuning a new board that has existing power integrity problems, target impedance is a real consideration that should be considered in your design.
Dual power supplies are circuits that generate two different output voltages from a single input source. The simplest method of generating dual output voltages is to use a transformer with two taps on the output winding. Bespoke transformers can have any voltage ratio depending on the number of windings in each part of the output side of the transformer.
With digital boards that are nominally running at DC, splitting up a power plane or using multiple power planes is a necessity for routing large currents at standard core/logic levels to digital components. Once you start mixing analog and digital sections into your power layers with multiple nets, it can be difficult to implement clean power in a design if you’re not careful with your layout.