By Joe Moxley, senior engineer, of Custom Electronics, Inc.

Passive components, which are generally thought of as inductors, capacitors and resistors, are ubiquitous in industrial and consumer electronics, forming the interconnectivity required for active devices. Total sales of passive devices, including modular devices, in 2009 was $22 billion, and even with the downturn in the worldwide economy, the market continues to grow, albeit somewhat more slowly than in the past. By far, capacitors account for the largest segment of the market, capturing 60 percent ($13 billion), with modular components accounting for 20 percent ($4.4 billion) with the balance going to inductors, resistors and other items classified as passive components. Modular components, such as DC/DC converter modules, while not strictly passive components, are included as many passive component manufactures produce them, which is a growing trend that will continue.

Passive components, as well as the entire cadre of electronic devices, are always driven by a market eager for smaller, cheaper and higher quality parts. For designers and manufactures of capacitors and other passive components, these three factors require an ongoing search for new materials, innovative packaging techniques, and manufacturing processes that translate to lower cost.

Manufacturers are always on the lookout for new materials or variants of older materials that can be incorporated into passive components. In the case of capacitors, this includes a wide variety of materials with dielectric properties that will enhance energy density, frequency response, ESR, ESL and temperature range. The multi-layer ceramic capacitor (MLCC) is an excellent example of a passive component that has enjoyed robust growth using a wide variety of dielectric materials and making improvements to device design . There are many engineered dielectric materials that have been used in MLCC devices, which allow an array of devices to be built to meet specific design requirements. EIA Class 2 dielectrics, for example, are available in various temperature and tolerance ranges, allowing manufacturers to produce capacitors for a particular purpose. Advances in material science have led to a burgeoning of passive components designed for a particular application, and this trend will only continue. Another example of the importance of new materials is found in the ultracapacitor arena; ultracapacitors range in value from 1 to 9000 F or more, and their energy density has been gradually increasing over the last decade through ongoing research efforts with the goal of making energy density on par with some battery types, such as lead acid storage batteries. The importance of new materials cannot be overemphasized. In the case of ultracapacitors, for example, if new electrolytes and/or electrode materials can be found that will enhance the energy density of these devices to be on par with lead acid storage batteries, it would represent a game changer in the industry, leading to the wholesale replacement of lead acid storage devices with ultracapacitors due to their superior operating performance. There are at least two major efforts to increase energy density of these devices by exploring the ramifications of new electrode design.

Packaging and manufacturing processes are also important. Again, the MLCC can be pointed to as an example. The rigidity of the ceramic substrate made MLCC devices prone to failures associated with flexure of circuit boards and/or vibration casing lead out connection failures due to cracking. The problem was solved by packaging the devices in such a way that the devices had “flexible” lead outs. The increase in the number of passive components available on the market today is astonishing to someone who has been in the passive component business for any length of time; this fact is driven home by the increase in the number of pages necessary to enumerate all the capacitor selections in a component catalog. There is little doubt that due to new materials, packaging techniques, and the demand for higher quality components, the number of passive components for specific applications will continue to grow and become a major trend in the passive component industry.

Modules will also continue to grow and become a major product line for many passive component manufactures. The value-added proposition of modular packages has grown in the last two decades and will continue to do so.

Passive components represent a growing industry that will be driven by customer demand for specialized passive components and passive components in modular packages. The proliferation of new materials and nano-scale materials will be utilized in the passive component market, as well as in innovative production processes. There is room for both small and large companies in the passive component industry, and the value-added proposition of modular devices will be most advantageous, especially for small specialty companies.

Footnotes: (1) MLCC devices had issues of cracking, which leads to failure due to lead fracture. In order to overcome this difficulty, one manufacturer developed a “flexible” inner connect, which is but a single example of device design. (2) Historical Introduction to Capacitor Technology, IEEE Electrical Insulation Magazine, Vol. 26, No. 1 (3) The superior performance of ultracapacitors in terms of charge-discharge cycle, charging rates that are a fraction of that for storage batteries, low maintenance, longer shelf life, and better performance at lower temperature constitute the reasons for wholesale replacement.