ROHM (headquartered in Kyodo, Japan), a world-famous semiconductor manufacturer, has launched three types of metal plate shunt resistor "PMR100" with rated power of 5W and resistance values of 0.5m Ω, 1.0m Ω 1.5m Ω new product.

Shunt resistor for current detection is mainly used for motor drive circuit, over-current protection of power supply and residual battery power detection. It has been widely used in automobile, industrial equipment, consumer electronic equipment and many other fields. To meet the energy saving requirements of various applications, it is necessary to use high-precision and highly reliable shunt resistors for precise circuit control. In addition, with the functional improvement of the application products, the installation density on the circuit board is getting higher and higher, which requires that the shunt resistor is smaller in size and higher in power. In addition, in the automotive field, it is very important to ensure high current detection accuracy under high temperature environment.

Resistors are ROHM's pioneering products. ROHM has always been leading the industry in the development of resistor products. Among them, the metal plate shunt resistor PMR series is well received by customers because of its rich product lineup, and has been used in many applications. This time, ROHM has further expanded the small and high-power "PMR100" product lineup, which supports the use in high temperature environment and high precision, by increasing the power and expanding the resistance range.

The new product achieves 5W rated power by adopting new materials with excellent temperature characteristics and pin temperature derating * 1. This belongs to the industry's ultra-high power rating in the 6432 size flat chip products with protective film. Compared with the previous 2W products in the PMR100 series, the rated power of the new product is increased by about 2.5 times, and compared with the 3W product, the rated power is increased by about 1.7 times. It can replace large and high-power products, so it helps to miniaturize the application products. In addition, the new product also guarantees the rated pin temperature of 130 ℃ * 2 (0.5m Ω, 1m Ω products) and the operating temperature range of - 65 ℃~+175 ℃, so as to ensure stable operation under high temperature environment. In addition, it also has excellent resistance temperature coefficient (TCR * 3) of ± 75ppm/℃, which can realize high-precision and reliable current detection.

Samples of new products have been sold since December 2023 (sample price: 250 yen/piece, tax excluded), and will be put into mass production gradually from March 2024. ROHM Electronics Philippines, Inc. (Philippines) is the production base of the previous and subsequent processes.

At present, ROHM is also developing smaller 4W products in the size of 5025 and 3225 in the PMR series, and plans to further expand the product portfolio. In the future, ROHM will continue to contribute to energy saving and miniaturization of applied products by continuously improving the performance of shunt resistors.

＜ About PMR Series ＞

PMR series is the most standard metal plate resistor in ROHM shunt resistor series, which covers seven standard sizes from "1005 (1.0mm × 0.5mm)" to "6432 (6.4mm × 3.2mm)" in resistor market.

In addition, by adopting ROHM's own resistance free structure, the problem of product temperature rise caused by local concentration of current is suppressed, which effectively solves the long-standing problem, thus widening the distance between electrodes. Even products with low resistance value of 0.5m Ω can easily carry out pattern design.

＜ Product lineup of PMR100 ＞

＜ Application examples ＞

The new products are commonly used in many fields of current detection applications.

・ On board: EPS, electric compressor, water pump, oil pump, door motor, ADAS controller, etc

・ Industrial equipment: power module, power regulator, electric tools, photovoltaic inverter, server power supply, UPS (uninterruptible power supply), base station power supply, etc. for industrial equipment

・ Consumer electronic equipment: white goods (air conditioners, vacuum cleaners, refrigerators, washing machines), etc

<Explanation of Terms>

*1) Pin temperature derating

In order to suppress the self heating phenomenon that may cause failure, it is necessary to make the product work at a temperature lower than the specified rated temperature (derating). Relative to the "ambient temperature derating" based on the ambient temperature of the device, the way of taking the pin temperature of the device as the judgment reference is called "pin temperature derating".

*2) Rated pin temperature

Indicates the maximum pin temperature of the product when the rated power of the product can be applied 100%. The rated pin temperature varies with the product series and size, and in some cases, it also varies with the resistance value.

*3) TCR (abbreviation of Temperature Coefficient of Resistance)

It refers to the "resistance temperature coefficient". The lower the value, the smaller the change of resistance value relative to the ambient temperature change, so as to restrain the fluctuation during equipment operation.