To create a surface-mount film resistor that is less susceptible to damaging surges, TT electronics' IRC Wire and Film Technologies Div. has certified its HSF Series to meet or exceed GR1089 lightning strike specifications. Typically, conventional devices that meet GR1089 are relatively bulky through-hole wirewound components, according to the company. Thick-film devices are more vulnerable to surges because the trimmed path of the resistive element provides a failure point where the resistor material narrows. The HSF Series is unspiraled, removing this failure mode under these types of strikes, even in the lower resistance values, where power is maximized.
The HSF Series resistors feature a power rating of 1 W at 70°C and a working voltage of 350 V. The devices come in resistance values of 5.9, 11, 27, 68, and 270 Ω, with a tolerance of ±10%, and TCRs to ±50 ppm/°C. Maximum operating temperature is 150°C. IRC will also produce devices outside these specifications to meet customer requirements. Typical pricing for the HSF Series resistors is approximately $0.18 each in quantities of 10,000. Lead-time is from stock to four to six weeks. Check out www.irctt.com/products.aspx?frmCategory=37.