Bosch Sensortec — BMM350 Magnetometer

The BMM350 from Bosch Sensortec is a 16-bit 3-axis magnetometer for products which need accurate heading information in a very small footprint. Based on tunnel magnetoresistance technology (TMR), the BMM350 is aimed at consumer and industrial systems such as AR and VR headsets, wearables, hearables, robots, vehicles, drones, and GPS-enabled products. 

While it is specified as a 16-bit sensor at a system level, the magnetometer internally uses higher-resolution digital representation, with magnetic and temperature data delivered in a 21-bit signed format within 24-bit registers, enabling more precise processing and measurement handling. 

Performance is a key strength. The BMM350 measures magnetic fields on the x, y, and z axes across a typical range of ±2000uT, while combining low current consumption with low noise. Average current consumption of 200uA at 100Hz in normal mode. The magnetometer is housed in a 1.28mm x 1.28mm x 0.5mm wafer level chip scale package. 

The BMM350 supports field shock recovery, enabling it to recover from excessively strong magnetic fields up to 400mT, tolerating fields up to 100 times the measurement range without performance degradation. This helps to maintain stable sensing in products exposed to transient magnetic disturbance. 

For intelligent sensing designs, the BMM350 can support far more than a basic digital compass. Bosch Sensortec highlights use such as head orientation for 3D audio, reduced pixel latency in AR and VR, indoor navigation in combination with an accelerometer, and positioning or speed detection in vehicles or industrial machines. Used alongside the BMI270 inertial measurement unit and BMP58x pressure sensors, the BMM350 can form part of a 10 DoF sensing solution for more accurate context awareness and heading estimation.