EMI filters from Knowles Precision Devices can be used in medical implants
Manufacturers of electronic equipment for hi-rel applications can struggle to meet stringent EMC and safety standards, says Knowles Precision Devices (KPD) as it releases a range of EMI components, under the Syfer brand. The EMI filters are designed to meet the needs of designers in the medical implantable and space sectors as well as industrial, automotive, aerospace and telecom applications.
The increasing use of surface mount filters over conventional panel mounted filters has simplified assembly methods, reduced production costs and enabled smaller volumetric efficiencies to be gained giving a greater choice of options to the designer – with shorter lead-times for development samples.
KPD’s efforts to refine its existing ranges includes exploring new ranges and to bring on board new materials, like lead free dielectrics.
For example, the Syfer E01 and E07 ranges of feed through MLCC C filters now have extended working voltages from 25 to 200V DC, and in certain cases up to 500V DC. These surface mount EMI filter three- terminal chip devices are designed to offer reduced inductance compared to conventional MLCCs when used in signal line filtering. The filtered signal passes through the chip’s internal electrodes with the ‘noise’ filtered to the grounded side contacts, resulting in reduced length noise transmission paths. Available in C0G/NP0 & X7R dielectrics, in case sizes 0805 to 1812. Current ratings are 300mA to 3A with voltage ratings of 25 to 200V DC (500V DC in some case sizes).
Conventional array filters can be replaced in medical implantable devices using the Syfer E03 (X2Y) range. Case sizes range from 0805 to 2220 for these integrated passive devices. They feature both common and differential mode capacitors in a single MLCC chip. C0G and X7R dielectric versions are also available as options. X7R dielectric versions are available with KPD’s FlexiCap termination which is recommended for new designs.
For both signal and power lines, the Syfer SBSP range of surface mount pi-filters ensure EMI filtering performance, says KPD. Suitable for telecomms, power supplies and industrial electronic equipment, the filters have an operating temperature range of -55 to +125 degrees C, ensuring they are also suitable for mil/aerospace applications. The use of X7R and C0G ceramic dielectrics sees capacitance values from 22pF to 150nF with a 1A current rating. They have working voltages up to 100V DC.
FlexiCap termination is used throughout the range and all versions are available with either tin or tin/lead finishes.