MLX90391 / 3D magnetometer for cost-effective applications
The MLX90391 is a 3-axis magnetometer specifically designed for micropower cost-sensitive applications. It measures magnetic fields along the X, Y, and Z axes using a combination of vertical and horizontal Hall-effect technology, and outputs 16-bit magnetic and IC temperature data over an I²C interface. Featuring four user-selectable magnetic range options (±65 mT, ±130 mT, ±260 mT, and ±520 mT), the device allows engineers to use the same IC for high-resolution position measurement or for robust external-magnet anti-tamper protection up to 500 mT in smart utility meters. Its standard TSOT23-6L package and familiar I²C interface enable a direct drop-in replacement, simplifying upgrades without PCB redesigns.
MLX90391 Key features:
- 16-bit Digital Output for magnetic and temperature data
- Three Wake-up on change / Interrupt modes
- Data Ready output for μC synchronization
- Built-in chip temperature compensation
- Runtime selectable modes (on-the-fly)
- Integrated configurable digital filter
- Individually selectable magnetic axes
- Four user selectable configurations of the magnetic range ±65 mT, ±130 mT, ±260 mT & ±520 mT
- I2C compatible with 0.1 MHz, 0.4 MHz & 1.0 MHz
- External synchronized measurement via I2C
- Two selectable I2C slave addresses in one device
- Power Down mode of 5nA current consumption
- Wide supply voltage from 1.7 V to 3.6 V
- Ambient temperature range from -40 °C to 125 °C
- TSOT23-6L (SE) package: RoHS, Green and Halogen free compliant
MLX90391 Applications:
- Anti-tampering – E-meters, Doors & Windows
- White goods – Smart knob & liquid levels
- Battery powered tools – Hairdryer & drill trigger
- Smart home – HMI thermostat & electronic lock
- Wearables – Smart watch digital crown & bezel
- Industrial – Linear & pneumatic actuators
- Gaming – Joystick, D-pads & Trigger buttons
- E-bikes – Forks and Gear position
- PC peripheral – Mouse roller
The chip integrates Wake-up on Change (WOC) logic with Static Delta and Dynamic Delta modes, allowing the host system to remain in deep sleep while the IC monitors magnetic field variations. Operating from 1.7 V to 3.6 V across -40C to 125C, it features an ultra-low 5 nA power-down mode for prolonged battery operation.
The MLX90391 offers synchronization options via an external trigger pin or an I2C command. Two I2C addresses (per device) are available by swapping SDA and INTB pins. Furthermore, it is available in two versions to offer more variety in I2C address options. In total, four pre-programmed MLX90391 can be placed on a single I2C bus.
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