High-rated X2 capacitors

EMI problems under control

A new series of high-rated X2 capacitors with up to 45 μF allows the construction of space-saving and low-inductance EMI filters.

The number of nonlinear loads in industrial and consumer electronics is increasing continuously. Whether it’s a frequency converter, PC or energy-saving lamp - hardly any appliance now draws sinusoidal current from the power network. The consequence is considerable pollution of the power system with harmonics and interference.

Ever-higher capacitances required

X2 capacitors are typically used for filtering. The rising proportion of harmonics as well as their high amplitudes require higher capacitances to assure a sufficient filter effect. To obtain these values, several capacitors are usually connected in parallel. However, parallel circuits have their own drawbacks, such as parasitic inductances and losses in the connecting leads. They also involve higher labor and material costs, as well as taking up more space on the circuit board.

Single-capacitor solution

To solve this problem, EPCOS has developed the new B3292*E/F series of X2 capacitors rated for up to 45 μF. The following example shows the potential for space saving that it offers: a filter with the required capacitance of 20 μF designed with five conventional 4 μF-X2 capacitors each with dimensions of 18.0 x 41.5 x 32.5 mm3 (W x L x H) has a volume of 121.39 cm3. In contrast, a 20-μF capacitor of the new B3292*E/F series with dimensions of 30 x 42 x 45 mm3 takes up only 56.7 cm3 – meaning a volume reduction of more than 50 percent. The footprint saving is even more impressive: the new solution from EPCOS occupies only 12.6 cm2 instead of 37.37 cm2 for the discrete capacitor solution, corresponding to a space saving of about two thirds.

For further information please visit:
www.epcos.de/web/generator/Web/Sections/Components/Page,locale=en,r=263282,a=849334.html

Samples are available at your local Sasco Holz Branch Office.