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Melexis Presents Low-Cost 500 mT-Range 3D Magnetometer
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.
www.melexis.com
Melexis announced the introduction of the MLX90391, a 3D magnetometer IC engineered for cost-sensitive, high-volume deployments. Utilizing vertical Hall technology, the sensor integrates wide selectable measurement ranges and digital power-management modes to prevent external magnetic interference in smart electricity, gas, and water meters while serving as a contactless alternative to mechanical switches and potentiometers.
High-Field Anti-Tamper Protection and Dynamic Measurement
The device measures magnetic flux density across three spatial axes (X, Y, Z) and features runtime-selectable measurement ranges of ±65 mT, ±130 mT, ±260 mT, and ±520 mT. This wide dynamic range allows a single integrated circuit to handle both high-field anti-tamper detection (up to 500 mT) and high-resolution position tracking.
Key features and system integration capabilities include:
- Digital Processing & Filtering: Delivers 16-bit digital output resolution for magnetic and temperature data, accompanied by runtime-selectable operating modes, individually selectable measurement axes, and an integrated configurable digital filter.
- Low-Power Architecture: Features a 5 nA deep sleep power-down mode, operating across a supply voltage range of 1.7 V to 3.6 V and an operating temperature range of -40 °C to 125 °C.
- System Synchronization & Wake-Up: Incorporates three wake-up-on-change interrupt modes that allow host microcontrollers to stay in low-power sleep until magnetic thresholds are crossed, alongside data-ready outputs and external measurement synchronization pins.
- Drop-In Compatibility: Housed in an industry-standard TSOT23-6L package with standard pinout and an I²C-compatible interface, enabling pin-to-pin migration from existing market alternatives without requiring board redesigns.
Target Markets and Contactless Control
While specifically addressing stringent anti-tamper mandates in high-growth regional smart metering markets such as India, the MLX90391 also targets contactless human-machine interfaces (HMI) across smart home appliances, white goods, electronic smart locks, power tool triggers, liquid-level sensors, gaming controllers, and e-bike gear selectors.
The MLX90391 complements Melexis’ existing 3D Hall sensor lineup, joining higher-precision Triaxis-based solutions such as the MLX90394.
Additional Context
This section details technical specifications not included in the original news release.
Vertical Hall-effect elements integrate planar semiconductor structures oriented perpendicular to the chip surface, allowing the sensor to detect in-plane magnetic flux vectors alongside standard perpendicular fields without requiring complex post-passivation ferromagnetic flux concentrators. In smart utility metering installations, external permanent neodymium magnets placed against meter enclosures can saturate standard current transformers or lock mechanical registers to conceal electrical consumption. By detecting magnetic field vectors exceeding 500 millitesla across all spatial orientations, the sensor issues hardware interrupt flags to host microcontrollers to log tampering timestamps and switch meters into fail-safe billing routines.
Operating over standard and fast-mode I²C buses (up to 400 kHz or 1 MHz), the sensor uses internal analog-to-digital converters paired with digital decimation filters to adjust oversampling ratios. By configuring single-measurement polling or automated duty-cycled autonomous sniffing modes, average current consumption can be maintained below 10 microamperes during continuous low-frequency scanning, preserving primary lithium-thionyl chloride battery lifespans in standalone gas and water utility meters for deployment lifespans exceeding 10 to 15 years.
Edited by Romila DSilva, Induportals Editor, with AI assistance.
While specifically addressing stringent anti-tamper mandates in high-growth regional smart metering markets such as India, the MLX90391 also targets contactless human-machine interfaces (HMI) across smart home appliances, white goods, electronic smart locks, power tool triggers, liquid-level sensors, gaming controllers, and e-bike gear selectors.
The MLX90391 complements Melexis’ existing 3D Hall sensor lineup, joining higher-precision Triaxis-based solutions such as the MLX90394.
Additional Context
This section details technical specifications not included in the original news release.
Vertical Hall-effect elements integrate planar semiconductor structures oriented perpendicular to the chip surface, allowing the sensor to detect in-plane magnetic flux vectors alongside standard perpendicular fields without requiring complex post-passivation ferromagnetic flux concentrators. In smart utility metering installations, external permanent neodymium magnets placed against meter enclosures can saturate standard current transformers or lock mechanical registers to conceal electrical consumption. By detecting magnetic field vectors exceeding 500 millitesla across all spatial orientations, the sensor issues hardware interrupt flags to host microcontrollers to log tampering timestamps and switch meters into fail-safe billing routines.
Operating over standard and fast-mode I²C buses (up to 400 kHz or 1 MHz), the sensor uses internal analog-to-digital converters paired with digital decimation filters to adjust oversampling ratios. By configuring single-measurement polling or automated duty-cycled autonomous sniffing modes, average current consumption can be maintained below 10 microamperes during continuous low-frequency scanning, preserving primary lithium-thionyl chloride battery lifespans in standalone gas and water utility meters for deployment lifespans exceeding 10 to 15 years.
Edited by Romila DSilva, Induportals Editor, with AI assistance.
