From military aircraft to electronic warfare defense systems, aerospace and defense applications are placing new demands on their power electronics. Defense electronics systems must function reliably for their lifetime while operating at higher voltages and wider temperature ranges, and all while becoming smaller, lighter, and consuming less power.

As countries around the world continue to work on more sophisticated ways to conduct military missions – including weaponry that can reach intended targets quicker with even greater accuracy while remaining virtually undetectable – aerospace and defense companies are pushing the missile speed boundaries. Military aircraft and weaponry today are capable of traveling at supersonic speeds and are even entering hypersonic speed territory. 

High reliability – this is what the industry demands for some of the world’s most important devices. From implantable devices going into the human body, to space and military devices, these applications are built to last under extreme conditions. To do so, they are made of high-quality components with appropriate additional testing to ensure long-term reliability.

Designing medical implantable devices for high reliability is crucial for a variety of reasons. First, given the life-critical functions performed by many medial implantable devices, and the invasive procedure required to implant medical equipment properly in the human body, it is imperative that all medical devices are designed to function reliably throughout their entire lifetime. Furthermore, since patient safety is paramount, any precautions to reduce the possibility of potentially life-threatening malfunctions, recalls, and replacement surgeries are necessary. And, beyond preventing patient safety issues, there may also be severe economic and legal implications for device manufacturers if an implantable device fails.

Today, millions of people around the world rely on pacemakers to help regulate their heart’s rhythm. A traditional pacemaker usually consists of a pulse generator that is about the size of a tea bag and implanted under the skin near the collarbone, and a wire, or lead, that runs through a blood vessel to the heart. The end of the lead has an electrode on it that touches the heart wall to deliver electrical impulses. However, in the last decade, innovations in pacemaker technology have led to the introduction of a new style of pacemaker, known as the leadless pacemaker, that is about 1/10th the size of a traditional pacemaker, or about the size of a vitamin (Figure 1).

When launching expensive mission-critical equipment and people into space, there is absolutely no room for failure of any component. Therefore, if you are an RF system designer working on an aerospace application, you must be sure you are selecting high-quality, high-reliability electronic components for all your designs. But do you have a process in place for this type of component selection? At Knowles Precision Devices, we know it can be a challenging to navigate component selection for aerospace applications as there are many combinations of standards and tests that can be performed to space-qualify parts.

In an ideal world, capacitors could be designed in a way where they would exhibit no resistance. However, this is physically impossible to achieve as there will always be some type of internal resistance in a capacitor that appears in series with the capacitance of the device. Known as equivalent series resistance (ESR), the level of this resistance will vary across capacitors depending on a variety of factors including the dielectric materials used, frequency of the application, leakage, and quality and reliability of the capacitor. The two graphs in Figure 1 show an example of how ESR can change as frequency increases across various capacitances on two different classes of ceramic dielectrics.

Space missions present a unique set of environmental challenges that demand high reliability down to the smallest electronic components. Mission failures could cost human lives. From in-flight systems to power supplies, every single system contributes to the success of a space project, so they must maintain high quality and safety standards for long durations.

There are two main mounting schemes for placing components on a printed circuit board (PCB): through-hole technology (THT) and surface-mount technology (SMT). Given its popularity over the last few decades, it’s no surprise that designers default to SMT, but there are advantages to both schemes that are worth exploring, especially for high-reliability application designs.

When an electrical device fails, oftentimes, the root cause can be traced to a field failure of a capacitor. While it is rare for the failure to be caused by a capacitor defect that was introduced during manufacturing, it can happen. This is especially true when multi-layer ceramic capacitors (MLCCs) are used versus other more simplistic capacitor types such as single-layer capacitors (SLCs) since the manufacturing process involves stacking many layers of dielectric and electrodes on top one another.