The increasing number of small motors and electronic control units, driven by the ongoing electrification and motorization of automobiles, is driving demand for compact shunt resistors for high-performance applications. As a result of this trend, ROHM began mass production of the PSR series in 2016, which has been very well received by the market ever since.
In order to meet the demands for a wider resistance range, ROHM now offers the GMR series with 5 mΩ to 220 mΩ and therefore with much higher resistance values than the PSR series.
By using special materials and structures, ROHM has achieved a 45 percent reduction in surface temperature compared to conventional products. As a result, the shunts maintain stable resistance not only during normal operation but also under overcurrent loads. Furthermore, the use of a high-performance alloy as the resistance metal provides an excellent temperature coefficient (TCR) even in the low-resistance range, ensuring greater accuracy and reliability. A special design reduces the module height to just 0.4 mm. The new GMR100 series is 47 percent thinner than existing solutions. In applications with stringent temperature requirements, such as in the automotive and industrial sectors, this frees up space, reducing development effort and enabling further miniaturization of the final products.
Key Features
1. Wide Product Range:
The GMR series offers a wider range of resistances than the PSR series (5 mΩ to 220 mΩ compared to 0.1 mΩ to 3 mΩ).
2. Patented Materials and Special Design Reduce Temperature Rise by 45% Compared to Conventional Products:
Typical shunt resistors are thermally destroyed at high power levels. However, ROHM has been able to significantly reduce the surface temperature thanks to a special design and patented materials. Thus, when using a 10 Ω resistor at 3W, the GMR100 limits the temperature rise to 100°C. In comparison, a conventional resistor reaches 181°C. This represents a reduction of no less than 45%.
Thanks to excellent heat dissipation, stable properties can be maintained both during normal operation and under overcurrent loads without any change in resistance values.
3. Excellent temperature coefficient of resistance, even at extremely low impedance ranges.
Typically, as resistance decreases, the temperature coefficient of resistance (TCR) increases. The GMR series ensures excellent TCR through the use of a high-performance alloy as the resistance metal, even in the low impedance range. This enables high-precision current measurement that is insensitive to heat, thus increasing application reliability.
4. Compact dimensions with reduced height.
The GMR100 series is offered in a standard 6432 (2512 inch) package, allowing for easy replacement. Due to its special design, the height of the shunt resistors has been reduced by 50 percent compared to conventional products, resulting in a 47 percent reduction in overall volume.
Application Examples and Availability:
The GMR100 series is the ideal solution for applications in the automotive sector (engine control units, electronic power steering, converters, etc.), in industry (uninterruptible power supplies or universal inverters), and in consumer goods (inverters for refrigerators, air conditioners, and washing machines).
Shunt resistors are already available in sample and OEM quantities.
