IMU delivers high efficiency and accuracy for embedded systems

By Alex Pluemer, contributing writer

STMicroelectronics recently introduced the LSM6DSO
inertial measurement unit (IMU), a highly accurate and power efficient always-on 3D accelerometer and 3D gyroscope system-in-package. 

Two key features contribute to the improved system-level power efficiency, according to ST. The new IMU features a 9K-byte FIFO capable of storing more data than comparable sensors, thereby allowing the system processor to sleep longer and make fewer data requests. The LSM6DSO also features a combination MIPI I3Cand SPI/I2C serial interface. The MIPI I3C interface
provides dynamic address assignment and follower-initiated communication as well as communication speeds up to ten times faster than I2C.

Faster and less frequent transmission results in the processor sleeping longer and lowers the system’s overall power consumption. The LSM6DSO also features an embedded programmable finite state machine, which off-loads simple, repetitive tasks, further lessening the burden on the processor and conserving system power.


The IMU provides high-level accuracy, featuring a full-scale acceleration range of between ±2 g to ±16 g and an angular rate range of ±125 dps to ±2000 dps. The sensors offer excellent overall noise performance with an acceleration noise density of 70
mg/√Hz and a rate noise density of 3.8 mdps/√Hz, as well as a configurable phase delay for OIS/EIS applications and typical ZRL of ±1 dps.  These features make the LSM6DSO well suited for enhancing camera performance and motion detection, as well as a variety of
other applications.

In addition, the sensor implements an ST-developed pedometer algorithm that utilizes floating-point math to reduce step-counter errors by 60 percent.  A false-positive rejection block recognizes train, bus and subway movements and differentiates them from normal steps, reducing
step-counter errors. The algorithm can be configured to enable tuning to particular user populations and their physical body parameters, thereby further enhancing accuracy.

The LSDM6DSO is priced at $1.99 for orders of 1000 pieces.