At Knowles Precision Devices (KPD), we handle the specialty components that go in the systems that can’t quit. We have the extensive resources and subject matter knowledge to innovate around the technical and environmental challenges facing high-impact industries including military, aerospace, and beyond.

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.

Trimmer capacitors are variable components used to calibrate RF circuits during manufacturing or servicing. These components allow for variable tuning--think oscillator frequency values or rise and fall times. Should values drift over the life of the device, trimmer capacitors can be recalibrated as needed. For sensitive applications like magnetic resonance imaging (MRI), these components help to optimize performance where any instability in time or temperature could impact the image output.

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).

Innovating essential high technology systems with demanding specifications is always challenging; making any sort of difference requires extensive resources and deep subject matter knowledge.

But that’s what keeps it interesting.

Healthcare professionals and patients rely on magnetic resonance imaging (MRI) technology to examine soft tissues and organs in the body to detect a variety of issues, from degenerative diseases to tumors, in a non-invasive manner. To do this, the MRI machine uses a strong magnetic field and computer-generated radio waves to produce cross-sectional images. Thus, the quality of the MRI depends on the uniformity of the magnetic field – even the smallest trace of magnetism inside an MRI scanner can disrupt the field and degrade the quality of an MRI image. 

From systems that diagnose, like a magnetic resonance imaging (MRI) machine, to implantable devices that treat patients, like pacemakers and implantable cardioverter-defibrillator (ICDs), highly reliable electronic components are necessary. While the functionality of these devices is quite different, the challenges associated with designing these devices, such as selecting failsafe electronic components designed for lifetime reliability and ensuring supplier partners can meet industry-specific standards, are shared. Let’s look more closely at some of the industry-wide challenges associated with electronic component selection for medical devices as well as some of the application-specific decisions medical device designers need to make to ensure these devices function consistently and reliably for the long term.

At Knowles Precision Devices, we thrive on working with companies who want to take technically challenging ideas and work through the details to figure out how to turn their seemingly impossible ideas into reality. This is because we are not limited to volume production and have extensive experience making specialty and custom parts. We are also familiar with the challenges associated with delivering high-reliability components as we supply many industries and applications that depend on the consistent functionality of custom-shaped parts. For example, we provide numerous space grade components and we are the only manufacturer who has developed planar array ceramic parts for the International Space Station. 

In part 1 of this two-part guide, we talked about the trade-offs you need to make when selecting the type of capacitor that will be the best fit for your application and the basics of trimmer capacitor design including dielectric material options. This second post focuses more on the details of trimmer capacitor specs and how to determine what's right for your application.

At Knowles Precision Devices, we purposely avoid commodity components. What we thrive on is doing the hard things. We handle the specialty components that go in systems that cannot fail and that operate at extremely high voltages, temperatures, or frequencies. Do you have a complex technical challenge with hard-to-meet performance, size, or other requirements? Bring it to us. It’s what we do.