Technical Analysis and Application Guide for SMU01 Open-Loop Hall Effect Current Sensor

1. One-Sentence Description

SMU01 is an automotive-grade current sensor based on open-loop Hall effect technology, specifically designed for high-precision and wide-range DC current detection in new energy vehicles and industrial fields, supporting a measurement range of ±1500A and meeting the requirements of extreme working conditions from -40°C to 125°C.

2. Core Features

• Open-loop Hall effect architecture: No hysteresis, low power consumption, directly sensing magnetic field changes through Hall elements.
• Ultra-high insulation performance: With a withstand voltage rating of 4.7kV RMS (IEC 60664 standard) and a creepage distance of ≥16.5mm.
• Wide dynamic range: A single package covers current detection from ±400A to ±1500A, flexibly adapting to different power requirements.
• High reliability: Passed the ISO 16750-4 vibration/impact test, suitable for harsh automotive environments.
• Digital output: Provides a 0-2V voltage signal proportional to the input current, supporting bus power supply (5V DC).

3. Core Technical Specifications

4. The Story Behind the Chip

SMU01 adopts LEM Group's patented open-loop Hall effect technology, whose core is to convert the magnetic field (B∝IP) generated by the primary side large current into a linear voltage signal through Hall elements. Compared with the traditional closed-loop scheme, it eliminates the compensation coil and drive circuit, achieving high cost performance with a simplified architecture. The ASIC chip integrated inside the sensor uses CMOS technology, and the thermal drift is controlled within ±0.04mV/℃ through a temperature compensation algorithm to ensure stable accuracy across the entire temperature range.

5. Design Philosophy

• Modular platform strategy: The same housing is compatible with multiple ranges (400A to 24000A), reducing customer inventory costs.
• Electromagnetic isolation design: Gas gap isolation between the primary side high voltage and the secondary side electronic circuit, complying with automotive functional safety standards.
• High-frequency response optimization: 35kHz bandwidth supports fast transient current detection, suitable for dynamic scenarios such as motor control.

6. Application Scenarios

• New energy vehicles: Current sampling for battery management systems (BMS) and motor controllers (MCU).
• Charging infrastructure: Real-time current monitoring of power modules in charging piles.
• Industrial automation: Overcurrent protection and energy efficiency analysis for frequency converters and UPS systems.
• Renewable energy: DC side current detection for photovoltaic inverters and energy storage systems.

7. Unique Advantages

• Zero insertion loss: No core reset circuit is required, avoiding the copper loss problem of traditional transformers.
• Strong anti-interference capability: Built-in RC filter (optional) to suppress EMC noise, in line with the ISO 11452-4 conducted immunity standard.
• Flexible deployment: Supports direct installation of the primary side busbar, saving space and wiring costs.

8. Must-Know for Engineers in Selection

• Range matching principle: Select the model according to the system's peak current (e.g., ±1500A corresponds to a maximum continuous 1500A load).
• Thermal design considerations: The temperature rise under full load should be less than 85℃ (derating is required when TA=125℃).
• Calibration requirements: It is recommended to perform zero-point and gain calibration in a 25℃ environment to compensate for initial offset errors.
• Layout specifications: Follow the PCB wiring guidelines to ensure that the primary side wire passes vertically through the center hole of the sensor to reduce stray magnetic field interference.

Conclusion

With its high precision, wide temperature range, and automotive-grade reliability, SMU01 has become a core component for current detection in new energy vehicles and industrial automation. Engineers need to balance range, thermal management, and anti-interference design according to specific application scenarios to achieve optimal system performance.