Shunt resistors for current sensing are primarily used for overcurrent protection in power supplies and battery level detection, as well as in motor drive circuits across a wide range of fields, including automotive, industrial equipment, and consumer electronics. To achieve the energy savings required for various applications, precise circuit control using high-precision and reliable shunt resistors is essential. Furthermore, as application functionality improves, circuit boards become increasingly dense, necessitating smaller, higher-power shunt resistors. Particularly in the automotive sector, ensuring high sensing accuracy even in high-temperature environments is crucial.
These new products achieve a rated power of 5 W using new materials with excellent temperature characteristics and terminal temperature reduction. This makes them best-in-class for 6432-size flat chip types with a protective film. With a rated power approximately 2.5 times that of conventional 2 W PMR100 products and about 1.7 times that of 3 W models, they can replace larger, high-power types, contributing to further miniaturization in various applications. Furthermore, a rated terminal temperature of 130 °C (for 0.5 mΩ and 1 mΩ products) and an operating temperature range of -65 °C to +175 °C are guaranteed, ensuring stable operation even in extreme temperature environments. The excellent resistance temperature coefficient (CTR) of ±75 ppm/°C ensures highly accurate current sensing.
ROHM continues to advance in coil development. By further increasing the wattage and resistance ranges, ROHM can expand the PMR100 series to include compact, high-wattage, high-temperature, and high-precision models, as well as 4W types in the smaller sizes of 1210 (0.12 in × 0.1 in) / 3225 (3.2 mm × 2.5 mm) and 2010 (0.2 in × 0.1 in) / 5025 (5.0 mm × 2.5 mm).
In the future, ROHM will continue to contribute to the miniaturization and energy savings of applications by improving the performance of its wide range of shunt resistors.
PMR Series
The PMR series features the most widely used metal plate coils in ROHM's shunt coil range.
Seven standard sizes are offered, ranging from size 0402 (0.04 in × 0.02 in) / 1005 (1.0 mm × 0.5 mm) to size 2512 (0.25 in × 0.12 in) / size 6432 (6.4 mm × 3.2 mm).
Furthermore, the adoption of a patented edgeless structure suppresses the product temperature rise caused by localized current concentration. This allows for a greater distance between electrodes, improving the ease of pattern design even with resistances as low as 0.5 mΩ.
PMR100 Range
Application Examples
The new products are universally compatible for current detection in a wide range of applications.
Automotive: electric power steering (EPS), electric compressors, oil/water pumps, door motors, ADAS controllers, etc.
Industrial equipment: industrial power modules, power conditioners, power tools, photovoltaic inverters, server power supplies, UPS (uninterruptible power supplies), base station power supplies, etc.
Consumer applications: household appliances (e.g., air conditioners, refrigerators, vacuum cleaners, washing machines), etc.
