Bourns offers a full range of current sense resistors covering a full range of requirements.
High Power Density: Bourns has the highest power density available with the ability to design resistors in 1206 cases (CRF 1206) with a constant current of 10 Amps (100 mV) and 2512 cases (CRA 2512) with a constant current of 17 Amps (170 mV).
High Accuracy: Bourns offers very high accuracy being able to provide TCRs as low as 15 PPM in the PWR220-25 series maganin foil resistors between 20 °C and 60 °C and 75 PPM in their CRA2512, CRA2010, CRF2512, CRF1206 stamped metal alloy current sense resistors.
High Operating Temperature: For applications requiring a high operating temperature, the PWR4412 is derated to zero watts at 325 °C ambient temperature while CRA2512 is derated to zero watts at 170 °C. Having such high operating temperatures allows designers to run the component at less than 100% power over a much wider operating temperature.
Small SMD: For designers who require small SMD current sense resistors with a power rating of 1W and temperature derating started from 80 °C, the CRA2512 is a good solution.
Hot Ambient Temperature / High Continuous Currents: Bourns Models PWR4412 and PWR4413 are designed for a wide range of environments where the ambient temperature could get quite hot and where very high continuous currents are required to be measured. They have the advantage of being very robust and capable of withstanding large inrushes of current.
Low Ohmic Wire: Bourns PWR4412 and PWR4413 Series consist of low ohmic wire with a TCR of +20 PPM which is formed, cut and welded to tin-plated copper terminations. The terminations are 1 mm in diameter and can carry up to 78 amps in current.
High Constant Currents: Bourns offers parts for very high constant currents such as models PWR4412, PWR4413 with a maximum current of 30 Amps or PWR220 with a maximum current of 50 Amps.
All models of the PWR220 or PWR263 series, whether thick film or manganin foil technology are able to dissipate high amounts of power and carry up to 50 amps of current, provided there is a sufficient thermal path between the resistor, its backplate and the mounting surface. The large the heat sink that the resistor can attach to, the lower the overall thermal resistance and high the amount of current that can be carried. The most important condition for operating this range of resistors is to keep the temperatures of the backplate 25 °C under power. The maximum surface temperature of the resistor typically should be 155 °C.