ROHM Semiconductor – MEMS accelerometer provides built-in pedometer, free-fall detection and other motion-sensor functions


The KX126-1063 from Kionix, a ROHM Semiconductor group company, is a three-axis MEMS accelerometer which is supplied with algorithms implementing a pedometer and functions for tracking orientation and detecting tap/double tap, activity and free-fall events.

It offers a user-configurable full-scale measurement range of ±2g, ±4g or ±8g, and an output data rate up to 25.6kHz. Its measurements of acceleration are very stable over the full operating-temperature range. It can survive extreme shocks.

The device can operate in a low-power stand-by mode when still. The threshold for triggering its wake-up and sleep functions is configurable to a level as low as 3.9mg.

The KX126’s sense element is fabricated using Kionix’ proprietary plasma micromachining process technology.

An ASIC integrated into the accelerometer’s package performs signal conditioning and implements intelligent user-programmable functions.

The accelerometer is supplied in a 2mm x 2mm x 0.9mm LGA plastic package which is pin-compatible with the KX122 from Kionix. An internal voltage regulator ensures stable operation over the supply-voltage range of 1.71V to 3.6V.


  • 0.6% non-linearity
  • ±2% cross-axis sensitivity
  • 0.7mgrms noise at an output data rate of 50Hz
  • Factory-programmed offset and sensitivity
  • 2,048-byte FIFO/FILO buffer can record data when being read
  • User-selectable low-power and high-resolution modes
  • Self-test function
  • Digital high-pass filter outputs
  • I2C and serial peripheral interfaces


  • Consumer electronics devices
  • Industrial equipment