For more than 3 million people in the United States, pacemakers and implantable cardioverter defibrillators (ICDs) are the life-changing technology they depend on. While both devices are implantable medical devices designed to improve the quality of life of people with heart failure, a condition where the heart beats irregularly, each device has a different purpose.
A pacemaker, shown in Figure 1, is an implantable medical device designed to help patients maintain a normal heart rate and rhythm. The small device is placed under the patient’s skin in their upper chest and contains a computer that senses when the heart is beating at an irregular rate or out of rhythm. When the pacemaker detects that the heart is out of rhythm, it sends low-energy electrical pulses to bring the heart back to a steady rhythm and rate.
Rather than helping to maintain a regular heart beat, an ICD is designed to prevent or prevent potentially dangerous arrhythmias that cause sudden cardiac arrest by using low- or high-energy electrical shocks (Figure 2). can become Like a pacemaker, an ICD is implanted under the patient’s skin and contains a computer that tracks the heartbeat and rhythm. The main difference between the two devices is that with an ICD, if the patient’s heart beats too fast or is too out of rhythm, the ICD will send a shock to get it back into rhythm. Some ICDs can also act like a pacemaker and send a signal when the heart rate is too slow.
Although pacemakers and ICDs perform different functions, there are many similarities between these two applicable medical devices. Because both devices are critical to the lives of the patients who need them, it is important that the tiny circuit boards inside these devices, which contain tiny electronics like capacitors, have high reliability (Hi-Rel). ) to be made using electrical components. .
Challenges of designing electrical components for life sustaining technology
Because both pacemakers and ICDs are implanted inside the body, these devices must be as small as possible. Today, medical device designers are focusing on innovating device designs to further reduce size and are currently working on new leadless pacemakers that are about 1/10th the size of traditional pacemakers. are Therefore, electrical components such as capacitors used in these devices must continue to be miniaturized, which can be very difficult.
A great option to help reduce capacitor size is the use of multilayer ceramic capacitors (MLCCs). Because multiple layers can be built into a single capacitor with an MLCC, the result is a single capacitor that provides the same capacitance level as using multiple SLCs connected in parallel. Although this multilayer design is slightly thicker (taller) than SLC, it reduces the overall footprint required for the capacitor to achieve the high capacitance required for pacemakers and ICDs.
In addition to the need for increasingly smaller capacitors, the capacitors used in these devices must also be extremely reliable. Although high reliability may seem like a subjective term, in the medical industry, high reliability has a very specific meaning – the component must be designed to maintain consistent excellence in quality and safety over a long period of time.
This is no easy task because these components must use established military specifications (MIL-SPECs) through rigorous testing and extensive screening to prove reliability. For medical components, MIL-PRF-55681 and MIL-PRF-123 are the most common screening specifications used. At a higher level, MIL-PRF-55681 specifies a mid-K stable dielectric designated as BX while MIL-PRF-123 defines high reliability, general purpose (BX and BR), and temperature stable ( BP and BG) covers general requirements. Ceramic Dielectric Fixed Capacitors, Through Hole and SMD. Screening using MIL-PRF-123 provides an increased level of confidence over MIL-PRF-55681 because the screening specifications are more stringent.
Knowles Precision Devices is here to help.
At Knowles Precision Devices we are experts in guiding device manufacturers through the MLCC selection process and working together to perform the necessary in-house testing and screening for your device at our facilities in the United States. We have decades of experience in developing high reliability MLCCs suitable for implantable medical devices such as ICDs and Pacemakers. This means you can be confident that our components will deliver the level of reliability and safety required to be on the circuit boards of your life-critical implantable medical devices.
We also understand that in addition to meeting the miniaturization and Hi-Rel requirements for capacitors described in this post, there are many other factors that improve capacitor selection, including materials, leakage resistance, durability and Price. That’s why we offer a wide variety of Hi-Rel capacitors that can meet the exact specifications you need for medical implantable devices. From basic electric charge storage to electromagnetic interference (EMI) and high-frequency noise filtering to signal absorption and smoothing, we have the most reliable options for your device.
Learn more about our high-reliability product offerings by downloading our high-reliability products brochure.