As a fundamental component of circuit design, equivalent series resistance (ESR) is the measurement of all the non-ideal electrical resistances in series with a capacitor. When current flows through a multilayer ceramic capacitor (MLCC) due to application of alternating voltage, heat is generated in the MLCC due to the losses, specifically ESR. As a result, this self-heating can cause various performance and reliability issues in the circuits of today’s more complex and smaller electronic systems.
CToday, the design and development of many applications, such as power electronics in electric vehicles (EVs), is driven largely by concerns about size and weight. This means the film capacitors traditionally used by electronics engineers aren’t always the best option. Instead, multi-layer ceramic capacitors (MLCCs) are emerging as an excellent alternative to film capacitors. Let’s review some of the considerations to keep in mind when you are deciding if making the switch is the right choice for your application.
As many industries, including RF and automotive, need to incorporate more features in less space, engineers are constantly looking for ways to do more in a smaller footprint. For example, there is often demand for more multi-layer ceramic capacitors (MLCCs) to achieve higher capacitance values while at the same time increasingly limited space is available. Thus, continuing to simply add capacitors inside an application to achieve a higher capacitance value is not a viable option.
When an engineer designs a circuit, he or she needs to ensure that each component will “do what it says on the box.” In multi-layer ceramic capacitor (MLCC) design, one area that often concerns engineers is the fact that capacitance can fluctuate with voltage, which is known as “DC bias” or “voltage coefficient.”
As countries around the world tighten emissions standards, the demand for fully electric vehicles (EVs) is increasing. However, for EVs to see mainstream adoption, manufacturers must address the primary consumer concerns: longer driving ranges and faster charging. To address these concerns, EV manufacturers are beginning to redesign their vehicles to switch from the 400V battery systems widely used today to 800V battery systems, which can offer twice the voltage and 2.7 times the power density compared to a 400V system.
Today, surface-mount multilayer ceramic capacitors (MLCCs) are used in incredibly harsh applications, resulting in increased concern from end users over the likelihood of reliability issues such as mechanical cracking. Thus, at Knowles Precision Devices our engineers are often asked if our capacitors offer flexible termination that increases the mechanical strength of our components, which helps mitigate these potential issues. Our customers can rest assured that not only do we offer flexible termination in our capacitors, we were actually the creators of the first flexible termination technology for MLCCs.