August 28, 2026, Tessendloh Hamm, Belgium – Melexis, a global microelectronics engineering company, today announced the introduction of the ultra-low-power MLX90391 3D magnetometer for cost-sensitive, high-volume applications. This chip offers real-time flexibility and a wide range of selectable measurement ranges, providing robust tamper-proof protection up to 500mT for smart metering instruments. In addition to metering applications, this compact sensor also provides an ideal contactless solution for upgrading rotary, linear, and human-machine interface (HMI) controls in smart home devices and white goods.
Tamper-proof protection has become a critical design requirement in the field of smart metering instruments, especially when manufacturers need to control system costs or design complexity, effectively detecting strong external magnetic fields that may interfere with instrument operation. Based on this customer need, the MLX90391 introduces Melexis's vertical Hall effect technology into a cost-effective product tier, integrating a flexible digital architecture, low-power operation, and compact integration, making it suitable for high-volume instrument deployments.
MLX90391 Features
This device supports triaxial magnetic field measurement, offering selectable ranges of ±65mT, ±130mT, ±260mT, and ±520mT. This allows a single chip to meet both high-sensitivity position measurement and tamper-proof detection under high magnetic fields. For customers already using other magnetometers, the MLX90391 provides a seamless migration path. It uses a standard TSOT23-6L package with compatible pin definitions and a familiar I2C digital interface, supporting direct pin-to-pin replacement, helping to reduce PCB redesign costs, certification overhead, and time-to-market. This allows manufacturers to easily enhance their tamper-proof capabilities while maintaining a compact module layout and existing high-volume production processes.
The MLX90391 integrates the digital functions required for low-power system designs, including a 16-bit digital output for magnetic field and temperature data, runtime selectable modes, independently selectable magnetic axes, and built-in configurable digital filters. Three different wake-up/interrupt modes allow the host system to remain in deep sleep until the chip detects a specific magnetic field change; while data-ready outputs and external synchronous measurement capabilities support collaborative operation with a microcontroller (MCU) in more complex sensing architectures. The device features a 10nA power-down mode, a supply voltage of 1.7V to 3.6V, and an operating temperature range of -40°C to 125°C, making it suitable for deployment in compact, periodically operating sensing nodes in harsh environments.
The introduction of the MLX90391 further enriches Melexis' 3D magnetometer product portfolio, which also includes solutions such as the MLX90394 based on Triaxis® Hall technology, suitable for applications with higher requirements for accuracy, noise, and industrial-grade performance. With the MLX90391, Melexis expands its product portfolio into more cost-sensitive high-magnetic-field applications such as smart meters. Furthermore, this device is also suitable for various non-contact position sensing scenarios, such as smart knobs, liquid level detection, electronic locks, handheld tool switches, game controllers, and gear shift detection for electric bicycles. It provides options for compact HMI functionality, avoiding the wear, tolerance, and reliability limitations that can arise from traditional mechanical switches, sliders, or potentiometers.
A Voice from Melexico
“Our goal in designing the MLX90391 was to deliver high magnetic field measurement performance at a competitive price,” said Minko Daskalov, Product Line Director at Melexico. “By leveraging our experience and strengths in vertical Hall effect technology, we provide smart instrument manufacturers with a compact, low-power solution offering robust tamper-proof protection up to 500mT.”
Melexico has always prioritized a deep understanding of customer needs across different application scenarios, driving product definition accordingly. The launch of the MLX90391 reflects this continued philosophy—translating specific requirements into semiconductor product designs that combine performance, cost, and broad applicability.
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