Source: Murata news
Murata Manufacturing Co., Ltd. has begun mass production of the BLM18DN Series of high-frequency ferrite bead noise filters for power supply use, which are designed to meet the increasing requirements for filtering in automotive electronics.
1．Background of Development
In the automotive industry, in line with the expanding functionality of automobiles in recent years such as self-driving and ADAS*1, the resolution of the automotive cameras used as sensors has been further improved and automotive networks connecting various ECUs*2 are becoming more advanced.
At the same time, the weight of the network cables and power cables supporting these functions has become a problem, and the implementation of Power over Coaxial (PoC), a technology that supports simultaneous transmission of power and data transmission on a single coaxial cable to reduce the weight of equipment installed in vehicles, is advancing apace.
PoC superimposed power lines (Bias T Circuit) require components with high impendence up to high frequencies and capable of carrying large currents. Murata has developed the BLM18DN Series in order to satisfy these requirements.
Employing Murata’s magnetic material technology and internal electrode formation technology, the BLM18DN Series fully realize the characteristics and reliability demanded of compact noise filters used in automotive circuits.
2．Product Features
The details of the BLM18DN Series’ features are as follows.
- High-impedance characteristics even in the 1GHz high-frequency band
- Compatible with a maximum rated current of 1400mA
- Dimensions of 1.6×0.8×0.95mm (length x width x height) thanks to Murata’s proprietary magnetic material technology, which supports high frequency, high impedance and large current transmission for the first time*3
- A lineup of four products to meet a wide range of customer needs
Table: BLM18DN Series Noise Filter Ferrite Bead
| Model |
Impedance
at 100MHz
（Ω）
|
Impedance
at 1GHz
（Ω）
|
Maximum DC resistance
（Ω）
|
Rated current （ｍA） |
|
| at 85℃ | at 125℃ | ||||
| BLM18DN151SH1 | 150（±25%） | 400（±30%） | 0.120 | 1400 | 900 |
| BLM18DN221SH1 | 220（±25%） | 650（±30%） | 0.210 | 1000 | 650 |
| BLM18DN381SH1 | 380（±25%） | 1100（±30%） | 0.325 | 850 | 550 |
| BLM18DN601SH1 | 600（±25%） | 1500（±30%） | 0.435 | 700 | 450 |
The operating temperature range is -55 to 125℃
3．Future Outlook
The performance required of automotive electronic components is expected to further increase as a result of the improving functionality and expanding use of electronics in automobiles. Murata will continue to engage in research and development in order to develop products that meet the needs of our customers with respect to compact dimensions, guaranteed temperature characteristics, etc.
*1 Abbreviation of Advanced Driving Assistance System
*2 Abbreviation of Electronic Control Unit used in automobiles
*3 According to research by Murata. As of December 2018.