Murata’s 150 ºC compatible chip ferrite beads suppress power line noise in automobile applications

Hoofddorp, The Netherlands: Murata has announced the BLM31KN_BH series of chip ferrite beads for use in automotive powertrain safety applications with a very high, guaranteed temperature capability of 150 ºC. The chip ferrite beads are aimed at the automotive market for use as noise suppression components in power line circuits installed in engine bays and LED headlights that require guaranteed performance at high temperatures.
In the automotive market, the need for noise suppression to counteract conductive and radiated noise has recently increased due to the development of motorisation of various functions including those in hybrid and electric cars. For example, the number of motor control circuits (with brushes) or inverter circuits (brushless) has increased with the motorisation of powertrains, requiring noise suppression components that are capable of dealing with large currents. Furthermore, in order to reduce vehicle weight – which is directly related to fuel economy improvement – the ECUs for engine systems and safety systems tend to be located in engine bays that reach high temperatures, and hence require noise suppression components capable of working in, and sustaining those high temperatures.
Murata has realised a product with the small package size of 3216 (3.2 x 1.6 mm) that supports the large currents suitable for power lines (120 ohm / 4 A at 125 ºC) by creating design specifications for internal and external electrodes for use in environments of 150 ºC, thus contributing to the creation of noise suppression designs for these power lines.
The BLM31KN_BH series conforms to the all-important automotive test standard AEC-Q200, and is available within the range of -55 to 150 ºC with derating of the rated current; it determines the rated current at ambient temperatures of 125 ºC and 150 ºC and guarantees the specifications and reliability in environments of 150 ºC. The beads’ impedance up to 1000 ohm is effective for noise suppression at 100 MHz.

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