High power density chip resistors for high continuous and momentary load applications

TT Electronics has launched its HPDC series high power density chip resistors. This specialist design is optimised for power management, actuator drive, and heating applications profitting from the enhanced heat transfer from the element to the terminal. Such high power density components save PCB area and boost reliability by restricting the temperature rise in the component hotspot.

“Aluminium nitride – with its wide-area solder terminations – gives TT’s HPDC series our highest power density to date. With this product, our customers can reduce the size of their power conversion designs while enhancing the reliability of the assembly through restricting the component hotspot temperatures,” said Brian Stephenson, director of Engineering, TT Electronics. “These features make the HPDC family ideal for applications with high momentary load conditions, such as power supplies, motor drives, power amplifiers, and actuator controls.”

The new chip resistors employ an aluminium nitride ceramic substrate, which provides about six times the thermal conductivity of alumina – the traditional substrate material for chip resistors. These chip resistors also provide large area terminations for enhanced thermal contact with a PCB. As a result, heat generated in the resistor element is effectively conducted away, decreasing the temperature rise. This allows these resistors to provide a high power density solution with ratings of 2.4W in 1206 and 3.5W in 2512 footprints. Short term overload performance is also improved at 4.7W in 1206 and 7.7W in 2512 for five seconds, making them ideal in active capacitor bleed circuits. Furthermore, these high power resistors can be employed in temperature-controlled heating applications in which the power applied is restricted only by the maximum element temperature of 155C and the maximum termination temperature of 110C.