Capacitors are essential passive components for designing any electrical circuit. But there are so many options to choose from with a wide range of specifications that it can be overwhelming to determine what capacitor may be the best fit for your application. One early decision that circuit designers must make is to determine if a single-layer capacitor (SLC) or multi-layer ceramic capacitor (MLCC) is the right fit for their application needs. 

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.

When designing a ceramic capacitor, the type of dielectric used will influence the characteristics of the capacitor and define its electrical behavior. At a high level, there are two types of dielectrics made with ceramics – paraelectric and ferroelectric. Dielectrics containing paraelectric (or non-ferroelectric) ceramics are known as Class I dielectrics. These dielectrics show a linear relationship of polarization to voltage and are formulated to have a linear temperature coefficient. Capacitors using a Class I dielectric have high stability across various temperatures, but have low permittivity, which means the capacitor will offer low capacitance.

As complex electronic systems become more prevalent in our daily lives, the demand for high-temperature, high-reliability components continues to increase. Standard electronic components have an operating temperature of -55 °C to 125 °C, but the number of applications requiring functionality above 125 °C is growing. Components in these applications, like capacitors, must maintain their functionality and take the heat (literally and figuratively) while powered. To meet the brief, material and design of these high-temperature components must deviate from today’s standard.

Explosives are dangerous by design. For applications involving detonation, like munition and down-hole exploration, explosives should be built to avoid unintentional or premature detonation caused by any rise in temperature or shock. These applications require a number of specialty components including capacitors that discharge high energy at temperatures up to 200°C.

Today, a wide variety of capacitors with a range of features are available, which can make it difficult for circuit designers and electrical engineers to determine the best fit for their application. To add to the confusion, there is somewhat of a misconception today that some capacitors, such as tantalum and Class II MLCCs, are interchangeable. But this is not always the case. Each capacitor type has distinct advantages and disadvantages that are important to understand to ensure you choose the right technology to best meet the needs of your specific application requirements. This post provides a brief overview of these two capacitor types as well as a variety of factors to consider when making your capacitor selection.