New thick film shunt resistors support higher power

ROHM has developed thick-film shunt resistors, LTR100L, optimized for industrial and consumer applications. Often used to detect current in battery protection and motor drive circuits, shunt resistors require higher accuracy to improve reliability and ensure high-efficiency operation.

Recent years have seen an emphasis on energy savings in the industrial and consumer fields, with efforts being made to reduce power consumption during drive operation by using motor inverters. At the same time, protection circuits are becoming more important in these fields as applications continue to increase in power.

The company has been expanding its considerable lineup, most recently with the GMR320 series of metal plate shunt resistors – released in February 2021. The devices feature a higher guaranteed rated power of up to 10W. Since April 2018, ROHM has produced the LTR50 series of low ohmic thick film shunt resistors rated at 2W. With these latest products, ROHM has expanded its lineup of thick-film shunt resistors to support an even higher power area.

The series achieves the industry’s highest-rated power of 4W in the 3264 size (3.2mm x 6.4mm) / 1225 size (0.12" x 0.25") by revising resistor materials and applying terminal temperature derating. This makes them ideal for current detection in motor control and overcurrent protection circuits for industrial and consumer applications, which are progressing towards higher power. In addition, optimisation of the element structure delivers best-in-class TCR (temperature coefficient of resistance) characteristics among thick-film shunt resistors. As a result, the temperature does not easily affect them, enabling high accuracy, high-reliability current detection.

Samples can be purchased with the following resistances of 10mOhm, 47mOhm, and 91mOhm). Moreover, various content and tools beneficial for design, including application notes, are available.