Copper barrier caps – just what the doctor ordered!

3rd December 2009

ES Admin

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Datasheet

Imaging systems such as scanners represent the largest and most vibrant sector of the medical electronics industry. Demand for non-magnetic components is increasing, especially for medical applications such as MRI equipment. UK-based component manufacturer, Syfer Technology, has developed a new range of multilayer ceramic capacitor devices dedicated to this market, featuring a copper barrier and tin finish.

The use of conventional nickel barrier terminations is not suitable due to the magnetic properties exhibited by nickel. Silver/palladium (Ag/Pd) terminations have been used in the past, but are no longer viable due to the increase in soldering temperatures necessitated by the use of lead-free solders, as dictated by RoHS requirements. The result has been solder leaching problems for Ag/Pd terminations, making an alternative termination essential.

Syfer’s solution is to use a copper barrier, which is non-magnetic, with a tin finish on top. The company offers a wide range of multilayer ceramic chip capacitors, available in C0G/NP0, High Q and X7R dielectrics. With the C0G/NPO and High Q dielectrics, parts are offered across the capacitance range from 0.1pF to 15nF (50V to 3kV). In addition, X7R capacitors range from 47nF to 6.8µF (16V to 2kV). Devices are packaged in case sizes from 0402 to 2225, depending on value. Operating temperature range for all non-magnetic devices is -55 to 125oC.

To meet high temperature 260ºC soldering reflow profiles as detailed in the medical electronics standard, J-STD-020, Syfer’s C0G/ NP0 dielectrics are supplied with sintered termination while X7R dielectrics feature Syfer’s award winning FlexiCap™ termination.