Corpus Christi, Tex. TT electronics IRC has developed the OARS-XP series to provide a current sense device with high current-carrying capability for power electronics circuits. Applications include surge and pulse circuits, AC power applications, and current sensing and feedback circuits.
The OARS-XP series of metal element resistors deliver power ratings up to 5 watts in a unique flameproof open-air, surface-mount package that offers the maximum heat dissipation for a printed-circuit-board (PCB) mounted component. Resistance values range from 1 mohm to 25 mohms (.001 ohm to .0025 ohms), with tolerances down to ±1%. Inductance values are less than 10 nanohenries, with an operating temperature range from -40°C to +125°C. Custom specifications are available.
The OARS-XP series resistors consist of a 0.25" wide metal element resistance alloy, welded to compliant copper terminals designed to handle thermal coefficient of expansion (TCE) mismatch between the device and the PCB. Unlike other resistor technologies such as thin-film, thick-film or foil devices, the open-air metal element will not experience degradation of performance at extreme temperatures, even up to 500°C (a conservative temperature rating for the alloy itself), IRC said. However, since most PCB solder materials typically melt between 183°C and 230°C, the solder will reflow long before the device itself experiences any heat damage.
IRC will provide specific recommendations for maximizing heat dissipation when developing PCB layouts and traces for the devices. Lead-free, RoHS-compliant and zero-ohm jumper versions are also available.
Pricing: $0.53 each in quantities of 10,000.
Availability: Lead time is from stock to 10 weeks.
Product information: current sense resistors
IRC, 1-361-992-7900, www.irctt.com