SMV/SMR Series Precision Chip Shunt Resistors
Precision chip shunt (current sensing) resistor
5W power rating
Resistance range 1mΩ to 4.7Ω
Tolerance options ±0.5%, ±1%, and ±5%
TCR 30 and 50 ppm/°C
Four-terminal surface-mount construction
Low resistance for minimal power loss in series current paths
High precision for accurate current measurement across temperature
What are the SMV/SMR Series Precision Chip Shunt Resistors?
The SMV/SMR series are precision chip shunt resistors designed for current sensing and measurement applications in surface-mount assemblies. Built as four-terminal devices, they separate the current-carrying connections from the voltage sensing connections, following the Kelvin measurement principle to eliminate lead resistance error from the measurement. This construction allows the resistor to deliver accurate voltage-drop readings even at very low resistance values, where conventional two-terminal sensing would be compromised by parasitic resistance in the solder joints and interconnects.
The series is rated at 5W continuous power dissipation, with a resistance range spanning 1mΩ to 4.7Ω — covering the milliohm values most commonly required for inline current sensing in power electronics. Tolerance options of ±0.5%, ±1%, and ±5% are offered, with temperature coefficients of resistance of 30 and 50 ppm/°C depending on the selected variant. The low TCR ensures that the resistance value — and by extension the current measurement — remains stable as the component self-heats under load, which is critical in applications where accuracy must be maintained across operating temperature ranges rather than only under benign laboratory conditions.
Current sensing using a shunt resistor follows Ohm's Law directly: a known resistance in series with the load produces a proportional voltage drop that is measured by a differential amplifier or current sense IC. The accuracy of this method depends entirely on the stability of the shunt resistance, making tight tolerance and low TCR the defining specifications. The SMV and SMR variants address different physical configurations within the same electrical family, allowing design engineers to select the appropriate package geometry for their PCB layout and thermal management requirements while sharing a common set of electrical parameters.
SMV/SMR Series Precision Chip Shunt Resistors Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: SMV/SMR
Resistor type: Current sensing
Description: Precision chip
Power Rating: 5W
Resistance (Ω): 1m~4.7
Tolerance (%): ±0.5, ±1, ±5
TCR (ppm/C): 30, 50
Applications of the SMV/SMR Series Precision Chip Shunt Resistors
Where RARA current sensing resistors are deployed in the field.
Battery management systems and state-of-charge monitoring — coulomb counting in lithium-ion and lead-acid battery packs requires continuous, accurate current measurement over long periods; the low TCR of the SMV/SMR ensures measurement accuracy is maintained across the battery's operating temperature range.
Motor drive and inverter phase current sensing — variable frequency drives, servo amplifiers, and brushless motor controllers use inline shunt resistors to close the current feedback loop for torque control, overload protection, and commutation timing.
Switch-mode power supply output current monitoring — SMPS designs use current sense resistors in series with the output rail or switching node to implement current-mode control, overcurrent protection, and load monitoring.
DC-DC converter and charging circuit current measurement — buck, boost, and flyback converters in portable devices, on-board chargers, and power modules require accurate shunt sensing for regulation and protection.
UPS and power conditioning equipment — uninterruptible power supplies use shunt resistors to monitor load current, battery discharge rate, and charging current across varying temperature environments.
Automotive power electronics — on-board chargers, DC-DC converters, and battery junction boxes in electric and hybrid vehicles require AEC-Q200 compatible current sensing with stable performance over the automotive temperature range.
Industrial automation and control panels — programmable logic controllers, servo drives, and power distribution modules use precision shunts for current monitoring in closed-loop feedback and protection circuits.
Test and measurement equipment — precision power analyzers, current clamp calibration references, and laboratory current sources use low-resistance precision shunts where measurement traceability and long-term stability are required.
Renewable energy inverters and storage systems — solar inverters and battery energy storage systems require accurate current measurement over wide load and temperature ranges for maximum power point tracking and state-of-energy monitoring.
Related Products of the WCR500 / WCR1000 Series Water Cooled High Power Film Resistors
Model: CS
Resistor type: Current sensing
Description: Chip
Power Rating: 1/20W~3W
Resistance (Ω): 1m~8000m
Tolerance (%): ±1, ±2, ±5
TCR (ppm/C): 100, 1000
Model: CSTN
Resistor type: Current sensing
Description: Chip
Power Rating: 1/16W~3W
Resistance (Ω): 50m~1000m
Tolerance (%): ±0.5, ±1
TCR (ppm/C): 50, 100, 200
Model: RS
Resistor type: Current sensing
Description: Thick film chip
Power Rating: 1/16W~2W
Resistance (Ω): 10m~976m
Tolerance (%): ±1, ±5
TCR (ppm/C): 200, 1500
Model: RTX
Resistor type: Current Sensing
Description: Chip
Power Rating: 1/8W~2W
Resistance (Ω): 50m~1000m
Tolerance (%): ±0.5, ±1, ±2, ±5
TCR (ppm/C): 75-300
Why Choose RARA Current Sensing Resistors
What sets RARA apart for engineers and procurement managers in industrial and automotive markets.
01
8 Sub-Categories
No other single supplier covers AEC-Q200 chip shunts, milliohm precision types, four-terminal Kelvin shunts, power metering, and 12,000A panel shunts under one ISO-certified roof.
02
Extreme Precision
HPS, UHPS, and PSS precision shunts deliver ±0.05% tolerance and 3 ppm/°C TCR — meeting the accuracy demands of EV battery coulomb counting, precision power analyzers, and billing-grade energy metering.
03
Automotive Qualified
Multiple AEC-Q200 certified models (BCS, LRA, ECS, BWR, TCS, PCBS) with IATF 16949 manufacturing certification — covering EV battery management, motor control, and charging applications.
04
Global Track Record
Trusted by Tesla, GM Korea, Proterra, Siemens, Rockwell, and Schneider Electric — deployed in EV powertrains, industrial drives, and utility metering systems across six continents.
