Shunt resistor features ultra-low profile

Rohm Semiconductor has claimed the industry’s lowest height, measuring 0.03-inch, for a 12-W metal-plate shunt resistor. The new PSR350 shunt resistor is optimized for high-power applications in automotive and industrial equipment.

(Source: Rohm Semiconductor)

While shunt resistors have been used in power modules in industrial equipment, the need for thin, double-sided cooled power modules in the main inverters for xEVs is increasing, which requires smaller power device chips like IGBTs and SiC MOSFETs and shunt resistors, said Rohm.

The challenge is conventional metal-plate shunt resistors reduce the cooling efficiency of power devices because of their high profile and decreasing the height has been difficult, said the company.

Thanks to Rohm’s vertically integrated production system, along with material and process optimization, the company achieved a thickness of 0.03-inch (0.85 mm), which is 50% smaller than conventional 12-W shunt resistors. It is the same technology that was used to develop the industry’s smallest (0.25 × 0.25-inch / 64 × 64mm) PSR330 15-W rated shunt resistor, which decreases size by about 65% compared to conventional products in the same class, said Rohm.

(Source: Rohm Semiconductor)

Measuring 7.9 × 5.6 mm (3222 package size), the PSR350 offers a resistance value of 0.27 mΩ with a ±1% tolerance. The shunt resistor operates over the temperature range of -65°C to 175°C.

The new product targets high current sensing in applications equipped with motors and/or Lithium-ion batteries. For industrial products, applications include power modules, power tools, PV inverters, server power supplies, UPS and base-station power supplies. They are also suited for automotive applications, including electronic power steering, electric compressors, main inverters, on-board chargers, DC/DC and battery management systems as well as consumer devices such as home appliances.

Rohm said it will expand the PSR line with the PSR100 0.2-mΩ model that extends the lower resistance limit from the existing 0.3 mΩ to enable detection of higher currents.