ROHM expands its PSR series with ultra-low ohmic shunt resistors for automotive and industrial applications

Compact designs contribute to improved performance in high power applications

ROHM's new ultra-lo-ohmic Shunt Resistors-PSR100

With its PSR100 series, ROHM offers a significantly more compact version of its proven PSR series. The PSR100 series ultra-low ohmic shunt resistors have a high-power capability and are suited to current measurement in automotive and industrial applications.

The new shunt resistors, which are based on a high-performance metal alloy as the resistive element, feature superior temperature coefficients (TCR) from 50ppm to 150ppm. Thanks to ROHM's innovative precision welding technology, they deliver a high rated power of 3W coupled with an ultra-compact form factor of 6.35mm x 3.05mm. Their resistance range covers 0.3mΩ to 3.0mΩ. The resistance tolerance is specified with F (1%). The operating temperature range is –55°C to +170°C.

The PSR100 series is the ideal solution for automotive and industrial applications as well as many other areas with high requirements in terms of performance and size. These include for example on-board chargers, electronic compressors and EPS in motor vehicles in addition to UPS and base stations.

PSR Series Shunt Resistors

High power applications supported
Shunt resistors are widely used in the automotive and industrial sectors for measuring current in high power applications. Due to the increasing demand for electric vehicles and the need to provide greater safety and efficiency, the automotive sector is seeing a shift towards computerisation and electro-mechanical systems. This has led to an increasing number of small motors and ECUs being used in the vehicles, which in turn drives up the demand for compact shunt resistors that can support higher power. To cater to this demand, ROHM has expanded its PSR series of high power low-resistance shunt resistors.

Higher rated power achieved using precision welding technology and high performance alloy

Excellent temperature coefficient of resistance – even in the ultra-low resistance region
Generally, the lower the resistance, the higher the temperature coefficient of resistance (TCR). In line with this, ROHM used a high-performance alloy as a high-resistivity metal, which ensures superior TCR, even in the ultra-low resistance region. The latest version is currently available with resistances from as low as 0.3mΩ, thus facilitating a wider range of applications.

Superior temperature coefficient of resistance - even in the ultra-low-ohmic region


Circuit Diagram

Circuit Diagram

Specifications

Part No. Size (mm)
[inch]
Rated Power
(+70ºC)
Resistance
Tolerance
Temperature*
Coefficient
of Resistance (ppm/ºC)
Resistance
Range (mΩ)
Operating Temp.
Range (Cº)
NEWPSR100 6.35 x 3.05
[2512]
3W F(±1%) ±150 0.3 -55ºC to + 170ºC
±115 0.5
±100 1.0
±50 2.0, 3.0
PSR400 10 x 5.2
[3921]
4W F(±1%) ±225 0.2
±175 0.3, 0.5
±75 1.0, 2.0, 3.0
PSR500 15 x 7.75
[5931]
5W F(±1%) ±250 0.1
±225 0.2
±150 0.3, 0.4, 0.5
±75 1.0, 2.0

◊ These products are under development, and therefore the specifications are subject to change without notice. Please contact a ROHM sales representative for more information.
* +20ºC to +125ºC

Terminology

TCR (Temperature Coefficient of Resistance)
The lower the value, the less resistance change with a change in ambient temperature. This makes it possible to suppress variations during device operation.