News & Updates
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.
Previously, I described the PCB fabrication operations relative to inner layer processing, lamination, drilling, and plating. The last step in the process is outer layer processing which is described below. Once the desired plated copper thickness of a PCB has been achieved, it’s necessary to etch away the copper between the features in order to define the outer layer pattern.
There are many factors at play in determining the impact of inductance on high-frequency power distribution systems. Two topic areas, inductance of the decoupling capacitor and inductance of the power planes, were addressed in earlier articles. This article will focus on the inductance of the capacitor footprint and via inductance from the capacitor footprint back to the PCB power planes.
High-speed buses, whether single-ended or differential, can experience any number of signal integrity problems. A primary problem created by propagating signals is crosstalk, where a signal superimposes itself on a nearby trace. The industry-standard PCB design tools in Altium Designer® already include a post-layout simulator for examining crosstalk. Still, you can speed up crosstalk analysis in parallel buses when you use a powerful field solver.
Any time-dependent physical system with feedback and gain has conditions under which the system will reach stable behavior. Amplifier stability extends these concepts to amplifiers, where the system output can grow to an undesired saturated state due to unintended feedback. If you use the right design and simulation tools, you can easily account for potential instability in your circuit models before you create your layout.
The concept of design variants entails taking a single PCB design, and then on the assembly side, modifying specific components used in the design. Either by not installing, not installing, or choosing alternate components as replacements on a specific assembly to ultimately create different end products. In that way, you could support multiple product lines. This article describes the approach to working with variants.
Before anything else, some advice. The revisions and lifecycle are an area that takes some planning. It used to be that Concord Pro was primarily for components, but now it has gone far beyond that. With the ability to store and manage many other items, including your various templates, projects, even PDF documents, not everything will have the same revision scheme. Concord Pro is so powerful that it can handle any revision scheme you’d want to set up.
Whether the board will be placed in a high pressure vessel or underwater, your design will need to withstand pressure to avoid failure. On the enclosure side, your vessel should be rated up to a certain pressure and may require frequent cycling to prevent implosion. On the electronics side, component selection and layout (especially at high voltage) become critical to preventing failure and ensuring reliability.
The first update of Altium Designer 20.2 and Altium NEXUS Client 3.2 is now available. You can update through the Altium Designer update system ("Extensions and Updates") or download fresh builds from the Downloads section of the Altium website. Click on "Read More" to see a list of all changes in this update.
The history of engineering, both electrical and mechanical, is littered with approximations that have fallen by the wayside. These approximations worked well for a time and helped advance technology significantly over the decades. However, any model has limits on its applicability, and the typical RLCG transmission line model and frequency-independent impedance equations are no different. Copper foil roughness modeling and related transmission line impedance simulations are just one of many areas in which standard models cannot correctly treat signal behavior.
Once you’re planning for production of any new board, you’ll likely be planning a battery of tests for your new product. These tests often focus on functionality and, for high speed/high frequency boards, signal/power integrity. However, you may intend for your product to operate for an extreme period of time, and you’ll need some data to reliably place a lower limit on your product’s lifetime. In addition to in-circuit tests, functional tests, and possibly mechanical tests, the components and boards themselves can benefit from burn-in testing.
If you remember your days in school, then you probably remember the feeling of happiness and celebration when you pass a big exam. You’ll feel the same sense of adulation when your board spin passes a barrage of pre and post assembly tests, but a complex design might not reach that stage unless you implement the right design for testability methods. There are some simple steps that can help your manufacturer identify and quickly implement important bare-board and in-circuit testing (ICT), especially on critical circuit blocks.
This article describes the best hints and tips for designers of rigid-flex circuits. These tips include choosing the most appropriate material, suggestions for coordinating the PCB with the manufacturer, and a set of rules to be followed while PCB design.
There are a number of factors at play when it comes to the impact of inductance on high-frequency power distribution systems. This article will focus on the inductance of the capacitor footprint along with the inductance of vias from the capacitor footprint to the PCB power planes. Included are the various types and sizes of footprints for ceramic capacitors as well as a footprint for a tantalum capacitor; how changing the footprint impacts inductance and test results obtained for different capacitors.
In order to properly suppress common-mode noise, differential pairs must be routed in parallel, with perfect symmetry, and with matched lengths. In real PCBs, meeting these three objectives isn’t always possible. Instead of eyeing out your different pair lengths, the interactive routing tools in Altium Designer make differential pair length matching easy. You can encode permissible length mismatches as design rules as part of controlled impedance routing, or you can manually perform differential pair tuning using a variety of meandering styles. Here’s how this works in Altium Designer.
Augmented reality, virtual surgery, limb replacements, medical devices, and other new technologies need to incorporate haptic vibration motors and feedback to give the wearer a full sense of how they are interacting with their environment. Unless these cutting-edge applications include haptic vibration and feedback, users are forced to rely on their other four senses to understand the real or virtual environment.
Over the last 20 years, electronic devices have become increasingly sophisticated. Less than two decades ago, just having a mobile phone to make calls was rare; today, our phones power our lives. To meet the growing demand for smartphone technology, technology has become faster, more functional, and intuitive. Improvements to the component base have streamlined processes while reducing manufacturing costs.