The low ohmic values maximize energy conversion efficiency and minimize power consumption, while the low thermal EMF minimizes sensing errors. WSL resistors are available in 0603, 0805, 1205, 2010, 2512, and 2816 cases with power ratings from 0.1 W to 2 W; WSR devices are available in 4527 packages with ratings of 2, 3 or 5W. The high power density of these new resistors allows the size of circuit boards to be reduced, which in turn increases manufacturing throughput and reduces material costs.
Both WSL and WSR resistors feature an all-welded construction and a solid-metal nickel-chrome or manganese-copper alloy resistive element. The components feature a very low inductance of 0.5 to 5 nH while delivering an excellent frequency response to 50MHz. A low TCR of under 100 ppm/°C minimizes resistance change caused by self-heating and high-temperature environments. Tolerances of ±0.5 and ±1% are available, maximizing current-sensing performance, saving energy, and enabling fast response times to switching currents. For devices with a ±1% tolerance, resistance values range from 0.001 to 0.5Ω for the WSL series and 0.001 to 0.2Ω for the WSR.
Both resistors are available with tin/lead or lead-free terminations; lead-free styles are also RoHS-compliant. Both series operate at temperatures from -65 to +275degC, allowing for operation in high-temperature conditions with minimal reduction (derating) of rated power. WSL and WSR Power Metal Strip® resistors are the ideal choice for all types of current sensing, voltage division, and pulse applications in motors, power supplies, instruments, and many other end products.