Current sense resistors offer industry's lowest TCR

11th July 2014

Nat Bowers

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Offering a TCR of ±2 ppm/°C, which the manufacturer claims is the industry's lowest for high-power current shunts, Vishay Precision Group has introduced the first devices in the S series of precision foil current sense resistors. The SHR, SHS, SNR and SPR resistors offer a range of power ratings from 1.5 in free air to 80W when mounted on a heatsink.

The S series components feature low resistance values of 0.002-50Ω, tight tolerances to ±0.1%, very low inductance, thermal EMF lower than 1µV/°C and maximum currents to 150A, with higher values available upon request. Operating over a temperature range from -40 to +130°C, the current sense resistors provide exceptional load-life stability of ±0.1% typical after rated power at 70°C for 2,000 hours.

The S series resistors provide highly accurate and reliable current sensing in power supplies, digital multimeters, current control systems, medical equipment, solar and wind inverters, AC/DC converters and battery chargers. They are available in a variety of epoxy packages and package sizes, including the standard TO-220 and surface-mount version.

Yuval Hernik, Senior Director of Application Engineering, VPG, comments: "Several years ago we decided to focus on developing resistive current sense devices with Kelvin connections that would allow quick and accurate current measurements. Current sensing circuits provide the data control that circuits need to operate properly, and foil resistors are among their fundamental building blocks. In the typical application, a controlling circuit monitors current flowing through a current sense resistor as a voltage drop across the resistor and directs parameter changes to ensure that optimum circuit performance is maintained."

Samples and production quantities of the S series current sense resistors are available now, with lead times of seven to eight weeks.