Würth releases application note on blocking capacitors

Electronics manufacturer Würth Elektronik has released a new publication in its series of application notes dealing in detail with challenging issues regarding the design of circuits, providing valuable tips for practical applications.

Application Note ANP098, ‘Effect of layout, vias and design on the blocking quality of filter capacitors’, is aimed at blocking capacitors, which filter out higher frequencies from the signal path by deriving RF signals superimposing a DC current against ground. Using real measurements and practically realistic simulations, PCB-layout techniques for filter and blocking capacitors are also described that are ideally suited for the supply pins of digital ICs.

The application note was written by field application engineer Andreas Nadler, whose job at Würth Elektronik is located in the Business Unit for passive and active components and who is responsible for the EMC-conform design of power-supply systems and the suppression screening of electronic modules. Nadler describes the effects of layout, vias and design on the blocking quality of filter capacitors, a topic that is otherwise dealt with in handbooks only at the theoretical level.

The fundamental task of blocking capacitors on supply pins is basically to short-circuit the clocked current loop of the digital circuits locally using low impedance. This reduces the radiated magnetic field strength and the RF interference currents coupled into the supply voltage level as much as possible. If the capacitors are optimally selected with regard to their impedance curve and geometrically optimally placed at the VCC pins, then the clocked RF current can be blocked in the best possible way.

The aim of Application Note ANP098 is to illustrate the influence that the MLCC design, the number of ground vias, and the placement of the filter components have on each other. In addition, it is clearly shown how unexpected problems can arise as a result of the unfortunate dimensioning of capacitor banks.

In addition to this, Würth Elektronik’s Wireless Connectivity & Sensors Division has released a Wireless Connectivity & Sensors Product Guide to make it easier for customers to select the right products for them by providing overviews, schematics and graphics on the technologies. Its 200 pages offer a wealth of information about the products and the technologies behind them for application development.

Würth Elektronik’s broad portfolio of radio modules with various common but also proprietary radio technologies forms the basis for new Internet-of-Things (IoT) applications. Equipping temperature, humidity, pressure or vibration sensors with minute power-saving radio modules is an important aspect of intelligent solutions. As adding ‘smart’ IoT features to its own products allows many possibilities to be offered, Würth Elektronik provides numerous examples and solution strategies in the Product Guide for Smart Factory, Smart Industry, Smart Home, Smart Building and other application areas.

“We explain the products and the technologies used and strive to provide ideas on how sensor technology and networking open up new options,” said Markus Eberle, Marketing Manager at Würth Elektronik. “Of course, we also provide our customers with advice and support — through to design-in assistance.”

Image credit: ©stock.adobe.com/au/ipuwadol

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