Vishay Foil Resistors division, a part of Vishay Precision Group, has introduced a low-value current-sensing resistor, the CSM3637P.
The resistor is capable of handling currents upto 40 A and the power rating has improved upto 5 W. It has an absolute TCR of 15 ppm/°C. The value of resistance ranges from 3 to 100 mW.
CSM3637P
The heat sink that is placed at the top of the foil resistor is responsible for such high power rating. The resistor is designed to reduce termination resistance by separating the current and voltage sensing leads. Also, the thermal EMF of the resistor is less than 3 microvolts/°C. This is made possible by ensuring contact between the welded terminals and the chip. This method of designing minimizes build up of parasitic voltage, which is commonly encountered in majority of current-sensing resistors.
The CSM3637P comes with 0.2% load-life stability at +70/°C for 2000 h at the rated power. This stability is five times greater than conventional current-sensing resistors. This feature makes the new current-sensing resistor suitable for applications such as power amplifiers, bridge networks, switching linear power supplies, medical and test equipment.
The CSM3637P's low absolute TCR reduces the errors caused by temperature variations. Therefore, the resistor can handle harsh environments and is suitable for radiation ridden environments, well logging equipment, oil exploration and underwater repeaters for cross ocean communication systems.
The stability of the resistor can be improved further through post manufacturing operations such as temperature cycling, accelerated load life and short-time overload.