The latest surface-mount technology (SMT) power resistors from Bourns have good pulse protection, a smaller footprint, and simple series dropping functions that enable cost-effective automated assembly (see the figure). Designated as the PWR2010, PWR3014, PWR4318 and PWR5322, the power resistors feature high power density, low temperature coefficient, and power ratings of 1/2 to 3 W. They feature the characteristics of a wirewound resistor in a surface-mount package, which proves improved pulse handling for greater stability over a wide temperature range and improved product longevity.
The SMT power resistors work well in high-volume, automated assembly and as drop-in replacements for higher-priced and larger footprint parts. A special contour maximizes the surface area of the device and minimizes the temperature rise of the package for improved stability over time. The temperature coefficient of resistance (TCR) is 20 ppm for resistance values greater than 10 O, 50 ppm for resistance values less than 10 O, and 90 ppm for resistance values less than 0.99 O.
The PWR2010, PWR3014, PWR4318 and PWR5322 power resistors are available now. Pricing falls between $0.48 and $0.77 each in 5000-piece quantities.