Raleigh, N.C. Resistor manufacturer Stackpole Electronics, Inc. has introduced a new surface-mount power resistor capable of handling up to 12 watts at 85°C. Available in 5-, 10- and 12-watt ratings, the HPC Series is available from 0.1Ω to 100 KΩ. All power ratings come in a 0.5 x 0.5 x 0.5-in. package size and are available in tape and reel as well as bulk packaging.
Unlike conventional 1, 3 and 5 Watt surface mount wirewound resistors, the HPC Series employs conventional thick film chip resistors bonded to the flat surface of a subminiature aluminum extruded housing. The aluminum housing has been designed such that heat is efficiently transferred from the initial resistor/aluminum interface to all other parts of the aluminum structure. The surface area of the aluminum housing is such that it will exhibit a precise thermal resistance to air moving over that complete surface area.
"Conventional surface mount resistors depend almost exclusively on the termination pads for heat removal," explained Kory Schroeder, product engineering manager for Stackpole. "The HPC Series differs markedly in this respect. While the housing has integral J-lead type pads, the design of the housing is such that it transmits only a fraction of the resistor-generated heat to the PCB. While at maximum power, even though the resistive element can be at 150°C, the PCB solder pads will remain well under 105°C.This control of heat movement away from the PCB to better reach moving air is achieved by careful selection of the aluminum cross-section, heat travel path lengths and overall surface area of the housing."
Typical pricing for the HPC Series of resistors is approximately $0.75 each, with lead times from 6 to 8 weeks.