CASR 6-NP/SP1 Closed-Loop Fluxgate Current Sensor

CASR6-NP/SP1 Product Overview

The CASR 6-NP/SP1 is a high-performance closed-loop fluxgate current sensor from LEM (Switzerland), rated at 6 A and designed for precise electronic measurement of AC and DC currents. As a global leader in electrical measurement transducers, LEM has accumulated decades of technological expertise, delivering reliable solutions across industrial, automotive, energy, and many other sectors.

The CASR 6-NP/SP1 employs closedloop (compensated) multi-range current sensing technology with an internal fluxgate sensor type. It provides highly accurate measurement of direct, alternating, and pulsed currents, while ensuring galvanic isolation between the primary and secondary circuits. Its compact PCB-mount design and insulating plastic case (UL 94-V0 rated) allow easy integration into spaceconstrained circuit boards.

CASR6-NP/SP1 Core Technical Advantages

Closed-loop fluxgate technology – accurate and reliable
Compared with traditional open-loop Hall-effect sensors, the advanced closed-loop fluxgate principle offers lower offset drift over temperature and superior noise immunity. The sensor outputs a ratiometric voltage signal and operates from a single 4.75 V ~ 5.25 V supply, making it extremely easy to use.

Bidirectional measurement – versatile for all applications
Supports bidirectional current detection, faithfully capturing current flow regardless of direction. The 6 A rated current fulfills demanding accuracy requirements for low-current scenarios.

Ultra-fast response – excellent dynamic performance
With a response time of just 0.3 µs and a frequency bandwidth from DC to 300 kHz, the sensor reproduces high-frequency switching ripple and transient current surges in real time with high fidelity.

High accuracy and linearity
Sensitivity: 104.2 mV/A; Linearity: ±1%; Accuracy: ±0.8%. Wide operating temperature range (–40 °C to +105 °C) ensures stable performance even in harsh environments.

Galvanic isolation – compliant with international standards
Primary-to-secondary isolation voltage: 1000 Vrms. Meets EN50178, IEC60950, IEC61010, IEC61326, and UL508 safety standards.

CASR6-NP/SP1 Key Technical Specifications

CASR6-NP/SP1 Typical Applications

Industrial drives and control – precise current monitoring and feedback control in AC variable-speed drives, servo motor drives, DC motor drives, and static converters.

Power management – current sensing and protection in uninterruptible power supplies (UPS) and switch-mode power supplies (SMPS).

Battery monitoring – accurate charge/discharge current measurement in battery-powered equipment.

Renewable energy and storage – current feedback in solar inverters and wind turbine converters.

Welding equipment – wide-dynamic-range current measurement in welding power sources.

Railway and traction – on-board energy metering and consumption monitoring.

Why Choose the CASR 6-NP/SP1?

Proven LEM quality – LEM is the benchmark in electrical transducers worldwide, renowned for high reliability and long service life. Backed by a 5-year warranty.

End-of-life – limited stock available – This model is currently in end-of-life status, with limited inventory on hand. For customers maintaining existing equipment or requiring small-batch production, this is your last opportunity to secure this part.

Excellent compatibility – Pin-compatible with the LTSR series, simplifying product upgrades. Its compact, low-profile design suits high-density PCB layouts.

Stable over full temperature range – Very low offset drift ensures measurement consistency from –40 °C to +105 °C.

High immunity to interference – Outstanding dv/dt immunity guarantees stable operation in high-EMI environments.