Materials expertise achieves 4W in 3264 size thick-film shunt resistor
Adding to its range of shunt resistors, Rohm has introduced the LTR100L thick-film shunt resistors. They are optimised for industrial and consumer applications.
The series achieves the industry’s highest rated power of 4W in the 3264 size (3.2 x 6.4mm) / 1225 size (0.12 x 0.25inch), says Rohm, by revising resistor materials and applying terminal temperature derating. The result is a series of shunt resistors suitable for current detection in motor control and over-current protection circuits for industrial and consumer applications. The resistors were developed in response to these applications increasing power demands. The optimisation of the element structure is claimed to deliver best-in-class temperature co-efficient of resistance (TCR) characteristics for thick-film shunt resistors. The TCT is less than 300ppm per degree C (at 10mOhm resistance) within the operating temperature range. This reduces the change in resistance value due to temperature changes compared with standard products by 50 to 65 per cent, enabling high accuracy current detection that improves application reliability, adds Rohm. They are therefore not easily affected by temperature, enabling high accuracy, high reliability current detection.
Samples can be purchased from online distributors Digi-Key, Mouser and Farnell. Initial samples will have resistances of 10, 47 and 91mOhm. There are design tools and application notes available online at the company’s website.
The company says that it will expand its resistor line up, from low to high power to achieve greater energy savings and reliability.
The company’s web-based simulation environment enables thermal simulation of shunt resistors in combination with power devices and ICs. These simulations allow thermal design to be simulated in advance, reducing design load. Rohm also offers current detection solutions using ICs and discrete components that contribute to greater circuit efficiency and miniaturisation.
