World’s smallest MEMS accelerometers save space in wearable and audio devices

Bosch Sensortec has launched the world’s smallest MEMS accelerometers, the BMA530 and BMA580.

Both accelerometers include built-in features which make them easy to design in: the BMA530 tracks activity with a step counter, and is especially suitable for wearable devices. The BMA580, which includes voice detection, is best suited to audio and hearing devices. 

The two accelerometers use an innovative wafer-level chip-scale package (WLCSP) design to reduce the board space that is needed: the board footprint is 0.8 mm x 1.2 mm, and the height is just 0.55 mm. These small dimensions make the sensors easier to accommodate in the densely populated board layouts in small consumer devices such as wireless earbuds. 

Alongside voice activity detection, the BMA580 offers an advanced feature set for audio devices. Typically, microphones consume a lot of power because they need to be always on to listen for voice activity. To avoid this power drain, the BMA580 uses bone conduction to detect the vibration of the user’s voice. This can trigger a signal to wake up the microphone from sleep, enabling substantial power savings when there is no voice activity. 

The BMA580 also enables user interaction with the host audio device in response to a tap on the device, for example to answer or end a call. The sensor software includes an algorithm that can distinguish between single, double and triple taps.

The new BMA530 acceleration sensor is ideal for gesture recognition in toys, fall detection in laptop computers, and power management functions such as putting a smartphone to sleep after it has been motionless for a period of time.

Both the BMA530 and BMA580 offer multiple power modes, and the BMA580 automatically switches from high-power to low-power modes to extend battery life. The accelerometers offer a flexible set of connectivity options, including an I3C interface.