High-power low-value auto-grade surface-mount shunt resistor

Now available from Farnell element14, TT /Welwyn's LRMAP3920 is a high-power low-value SMT shunt resistor. With values down to 200µohm and a power rating on FR4 of 5W, the maximum measurable current is over 150A, and in most cases restricted only by the capacity of the PCB tracks. In addition to the 5W rating for FR4 PCB mounting, an even higher 10W power rating may be achieved for assemblies on thermal substrates such as DBC (direct bonded copper) ceramic or IMS (insulated metal substrate), making the parts ideal for power hybrid modules, says the company. By offering AEC-200Q qualification, the LRMAP3920 provides the assured reliability of a true automotive-grade component. With their very low values, the LRMAP3920 resistors minimise the energy wastage normally associated with including a series resistor in the high current circuit. Additionally, the parts’ low thermal impedance minimises heating of the resistor itself, which in turn further improves reliability. Offering high reliability under inrush and momentary short circuit conditions, LRMAP3920 resistors feature a high energy-surge capability up to 14J. The resistors’ typical load life stability of ±0.5 per cent, together with TCRs down to ±50ppm/C and thermal EMFs less than 2µV/C, result in only a small part of the designer’s error budget being consumed, enabling more design freedom elsewhere in the circuit. The resistors are manufactured using the latest bulk metal technology with e-beam welded copper terminations to deliver very low surface temperatures and excellent surge energy performance. In short, LRMAP3920 offers highly stability, accurate current sensing of AC and DC currents up to 150A in a compact, surface-mount format.