ADXL345 Digital iMEMS® Motion Sensor

ADI's ADXL345 ultra-low-power digital accelerometer has an output data range that scales from 0.1 Hz to 3.2 kHz, unlike competing devices, which have fixed 100 Hz, 400 Hz, or 1 kHz data rates. This allows portable system designers to better manage energy consumption by precisely allocating power for a given system function and reserving unused power for other uses. The ADXL345 measures dynamic acceleration resulting from motion or shock and with a 10,000-g shock rating is well suited for applications such as hard-disk drive protection in personal computers.

Featuring resolution of 4-milli-g / least-significant bit (LSB) across all g ranges, single tap and double tap detection, activity and inactivity detection, free fall detection, and user-programmable threshold levels, the new accelerometer also includes I²C and three- and four-wire serial peripheral interface (SPI) digital interfaces and a voltage range of 1.8 V to 3.6 V.

The ADXL345 motion sensor incorporates an on-chip first-in / first-out (FIFO) memory block that stores up to 32 sample sets of X, Y, and Z data. By sampling input data to determine if the system should be actively responding to a change in movement or acceleration, the new motion sensing devices save additional system power by off-loading that function from the host processor. Typically, a host processor consumes a dominant amount of system power budget, so allowing it to remain in sleep mode as long as possible can dramatically decrease overall power usage upwards of 75% of the budget, when utilized effectively. The ADXL345 is supplied in a small, thin, 3 mm x 5 mm x 1 mm, 14-lead, plastic package.