Reference Design

A system-level evaluation board that combines ROHM's IC and discrete products. We have already solved not only the characteristics of individual products but also the problems that may occur when combining them to build a system, thus contributing significantly to the reduction of development time for our customers.

100A shunt resistor and operational amplifier current sense circuit reference design


Low-side current sensing circuits are used for functions such as current (voltage) control, overcurrent limiting, and remaining battery level detection in the automotive and industrial equipment fields. Low-side current sensing circuits realized with shunt resistors and current-sensing amplifiers are the most common compared to other systems. REFSENS003 is a current sensor reference design of a shunt resistor and current sensing amplifier. We are releasing design data and selling reference boards, so please use them as design references and help reduce design man-hours.


  • The simplest current sense circuit with shunt resistor and operational amplifier (LMR1802G)
  • High power shunt resistor PSR400 2mΩ 4 in parallel
  • Current sense range: up to 100A
  • Thermally designed to keep each component within its absolute maximum rating even at a detected current Iin = 100A and an ambient temperature Ta = 85°C


Name of reference board designREFSENS002
Name of reference boardREFSENS002-EVK-001
Circuit systemOperational amplifier current sense circuit using shunt resistor system
Input voltage 1
(equipped device)
2.7 to 5.5V (LMR1802G-LB)
Input voltage 2
(sensing line)
~26V (Terminal protection by Zener diode)
Output systemAnalog voltage value
Dimension90mm x 80mm

Application examples

  • Switching power supply for industrial equipment
  • Motor drive for industrial equipment
  • Other current sense for industrial equipment

Reference Board Image

Product namefeatureSpiceUn-encrypted Spiceweb simsymbol&
3D Modelthermal
Calc toolEVK, Eval board
for individual product
LMR1802G-LBLow Noise, Low Input Offset Voltage CMOS Operational Amplifier-----
PSR400ITQFJ2L00High Power Type Metal Plate Shunt Resistor-------
TDZV5.1High reliability Small mold type-----

Design Data

Related Reference Design