As the backbone of the X-ray machine, X-ray tubes produce the radiation that generates the electromagnetic waves known as the “X-ray.” This is done by using a high voltage to accelerate the electrons released by a hot cathode to a high velocity. Those electrons then collide with the anode, which is a metal target usually made of tungsten. This process requires an input voltage typically ranging from 180 to 480 VAC with a power supply that transforms and steps up the voltage to extremely high voltage outputs ranging from 10kV and 120kV DC. A high-level diagram of the power supply required to power the X-ray tubes is shown in Figure 1. 

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).

If you are a medical device engineer working to improve the longevity for implantable devices such as pacemakers, defibrillators, insulin pumps, cochlear devices, or bladder stimulators, be sure to checkout our latest on-demand webinar – The Importance of High Reliability for Medical Implantable Devices.

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.

If you’re struggling with the challenges of ensuring high-reliability with your medical device electronics, you won’t want to miss our upcoming webinar sponsored by GlobalSpec, Using High-Reliability MLCCs for Medical Implantable Applications, on Thursday, November 4 at 11:00 am EDT.

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.