500 mT-Range 3D magnetometer

Melexis introduces the MLX90391, a low-power 3D magnetometer for cost-sensitive, high-volume applications. Delivering on-the-fly flexibility and wide selectable ranges, it provides smart utility meters with robust tampering protection up to 500 mT. Beyond metering applications, this compact sensor offers an optimal contactless solution for upgrading rotary, linear, and HMI controls in smart home devices and white goods.

Anti-tamper protection has become a critical design requirement in smart metering, particularly in India, where manufacturers need to detect strong external magnets that may be used to interfere with meter operation, without increasing system cost or design complexity. Driven by this clear customer requirement, the MLX90391 brings Melexis’ vertical Hall technology into an ideal cost-performance class, combining a flexible digital architecture, low-power operation, and compact integration for high-volume meter deployments.

The device measures magnetic fields across three axes. It allows engineers to select from ±65 mT, ±130 mT, ±260 mT, and ±520 mT ranges, enabling the same IC to address both sensitive position measurement and high-field anti-tamper detection. For customers already using alternative magnetometers, the MLX90391 also provides a direct migration route. Its standard TSOT23-6L package, matching pinout, and familiar I²C-compatible digital interface support pin-to-pin replacement, reducing PCB redesign effort, qualification overhead, and time to production. This makes it easier for manufacturers to strengthen their anti-tamper capabilities while preserving compact module layouts and established high-volume manufacturing flows.

The MLX90391 integrates the digital functions needed for practical, low-power system design, including 16-bit digital output for magnetic and temperature data, runtime-selectable modes, individually selectable magnetic axes, and an integrated, configurable digital filter. Three wake-up-on-change/interrupt modes allow the wider system to remain in deep sleep until the IC detects a defined magnetic field change, while data-ready output and externally synchronized measurement support microcontroller unit (MCU) coordination in more complex sensing architectures. With a 5nA power-down mode, 1.7V to 3.6V supply range, and -40°C to 125°C ambient temperature operation, the device is suited to compact, duty-cycled sensing nodes even in challenging deployment environments.

The MLX90391 sits alongside Melexis’ broader 3D magnetometer family, including Triaxis-Hall-based solutions like the MLX90394 for applications requiring higher accuracy, lower noise, and more demanding industrial-grade performance. With the MLX90391, Melexis extends its portfolio into more cost-sensitive, high-field applications such as utility meters. It also serves a wide range of contactless position sensing applications, such as smart knobs, liquid-level sensing, electronic locks, handheld tool triggers, gaming controls, and e-bike gear position sensing. Ultimately, it provides a reliable choice for compact HMI functions where mechanical switches, sliders, or potentiometers could introduce wear, tolerance issues, and reliability constraints.