LRE Series Metal Alloy Low-Resistance Resistors
The LRE Series is a range of lead-free, halogen-free, RoHS-compliant metal alloy low-resistance resistors in miniature surface-mount footprints, optimised for current sensing in compact, high-precision electronic products. Power ratings span 1/6W to 1W and resistance values cover 1mΩ to 60mΩ depending on case size, with tolerance options of ±0.5%, ±1%, ±2%, and ±5%. The operating temperature range is −55°C to +150°C.
Nine case sizes are offered — LRE0306, LRE0402, LRE0508, LRE0603, LRE0612, LRE0805, and LRE1206, plus four-terminal variants of the LRE0306 and LRE0612 — extending from the compact 0.85mm × 1.60mm body of the LRE0306 up to the 3.20mm × 1.60mm LRE1206. The four-terminal variants of the LRE0306 and LRE0612 provide separate current-carrying and voltage-sensing contacts in a Kelvin configuration, enabling more accurate resistance measurement in circuits where lead and contact resistance would otherwise introduce error. All variants are supplied on 8mm tape and reel at up to 10,000 pieces per reel for automated placement.
TCR varies by package and resistance value, ranging from ±50ppm/°C at the higher resistance values in larger packages to ±600ppm/°C in the sub-3mΩ range of the LRE0402. Rated continuous currents range from 9.1A for the LRE0402 at 1/4W up to 63.2A for the LRE0612 and LRE1206 at 1W, reflecting the progressively larger element geometry and thermal dissipation capacity of the larger footprints.
What are the LRE Series Metal Alloy Low-Resistance Resistors?
The LRE Series consists of miniature surface-mount current sensing resistors built from precision metal alloy elements, targeting applications where the available board area is too small for the LR Series packages but where the accuracy and stability of a metal alloy construction are required. The series spans footprints from the sub-millimetre LRE0306 — measuring just 0.85mm × 1.60mm — up to the 3.20mm × 1.60mm LRE1206, filling the space between chip resistor form factors used in portable and consumer electronics and the larger power-rated packages used in industrial and automotive applications.
The metal alloy resistive element is the defining technology choice of the LRE Series. Unlike thick-film alternatives, the metal alloy construction delivers resistance values and TCR figures that remain stable across temperature and over the component lifetime, without the trimming artefacts or moisture sensitivity that can affect thick-film elements at low resistance values. This makes the LRE Series suitable for precision current measurement where the resistor itself must not introduce drift or non-linearity that would degrade the accuracy of the sensing circuit.
The two-terminal variants of the LRE0306, LRE0402, LRE0508, LRE0603, LRE0805, and LRE1206 use standard two-pad SMD land patterns and are compatible with conventional reflow soldering processes. The four-terminal LRE0306-4T and LRE0612-4T add separate voltage-sensing pads to the body, providing a Kelvin connection that eliminates the resistance of the solder joint and PCB traces from the measurement. This is particularly relevant in the lower resistance values of the range, where solder joint resistance can represent a non-trivial fraction of the total element resistance and where the additional accuracy of a four-terminal measurement is warranted.
Short-time overload is qualified at four times rated power for five seconds, with resistance change not exceeding ±0.5% for all types except the LRE0612, which is rated to ±1.0%. Environmental qualifications follow JIS C5201-1 and MIL-STD-202 methods, covering solder heat resistance at 260°C, solderability at 245°C, 1000-hour high-temperature storage at +150°C, 1000-hour low-temperature storage at −55°C, 1000-cycle rapid temperature change from −55°C to +150°C, vibration, moisture resistance, bias humidity at 85°C and 85% RH for 1000 hours, and a 1000-hour load life test at rated power. Marking follows a four-digit format using the letter ‘R’ or ‘m’ to denote the decimal position, with some of the smallest packages — LRE0306, LRE0402, LRE0508, LRE0603, and LRE0805 — supplied without body marking due to the limited surface area available.
LRE Series Metal Alloy Low-Resistance Resistors Specifications
A practical overview for engineers and procurement teams evaluating resistive solutions.
Model: LRE
Resistor type: Metal alloy
Description: Low resistance
Power Rating: 1/6W~1W
Resistance (Ω): 0.2m~300m
Tolerance (%): ±0.5, ±1, ±2, ±5
TCR (ppm/C): 1-175
Applications of the LRE Series Metal Alloy Low-Resistance Resistors
Where RARA metal clad resistors are deployed in the field.
Power supply current sensing — monitoring output or input current in miniaturised switched-mode and linear power supplies where the small LRE footprints permit current sensing on densely populated boards.
Battery pack management — charge and discharge current measurement in lithium-ion cells and battery modules for portable devices, where the LRE0306 and LRE0402 occupy minimal board area while delivering stable metal alloy measurement accuracy.
LED driver circuits — output current sensing in compact constant-current LED drivers for solid-state lighting, display backlighting, and portable illumination products.
Measuring instruments and precision test equipment — shunt resistors in handheld and benchtop instruments where stable, low-TCR elements are required for accurate current measurement across operating temperature ranges.
Wearable and portable consumer electronics — current sensing in smartwatches, fitness trackers, hearables, and other miniaturised devices where the LRE0306 and LRE0402 provide the smallest available metal alloy shunt in an SMD outline.
Motor drive and fan control circuits — phase current sensing in small brushless DC motor and fan driver ICs, where the LRE0508 and LRE0603 packages balance current-handling capacity with compact footprint requirements.
DC-DC converters and point-of-load regulators — inductor current sensing and output current monitoring in synchronous buck and boost converters integrated into space-constrained power modules.
Automotive electronics — current sensing in body electronics modules, battery management units, and low-power control circuits requiring RoHS and halogen-free compliant components across the −55°C to +150°C operating range.
Industrial control and automation — current feedback in field device transmitters, sensor power supplies, and compact control modules where low-resistance, low-profile sensing elements are needed within tight PCB area budgets.
Related Products of the LRE Series Metal Alloy Low-Resistance Resistors
Model: MFF
Resistor type: Metal foil
Description: Low resistance chip
Power Rating: 0.33W~4W
Resistance (Ω): 0.5m~100m
Tolerance (%): ±0.3, ±0.5, ±1
TCR (ppm/C): 30-100
Model: MFR (Metal foil)
Resistor type: Metal foil
Description: Low resistance chip
Power Rating: 0.33W~5W
Resistance (Ω): 1m~700m
Tolerance (%): ±0.5, ±1
TCR (ppm/C): 50, 75, 100
Model: MFF
Resistor type: Metal foil
Description: Low resistance chip
Power Rating: 0.33W~4W
Resistance (Ω): 0.5m~100m
Tolerance (%): ±0.3, ±0.5, ±1
TCR (ppm/C): 30-100
Model: MR
Resistor type: Metal alloy
Description: Low resistance
Power Rating: 2W, 3W, 5W
Resistance (Ω): 4m~100m
Tolerance (%): ±1, ±2, ±5
TCR (ppm/C): 50, 75, 200
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.
