Adxl345

3-Axis, ±2 g/±4 g/±8 g/±16 g Digital Accelerometer ADXL345
FEATURES
Ultralow power: as low as 23 µA in measurement mode and 0.1 µA in standby mode at VS = 2.5 V (typical) Power consumption scales automatically with bandwidth User-selectable resolution Fixed 10-bit resolution Full resolution, where resolution increases with g range, up to 13-bit resolution at ±16 g (maintaining 4 mg/LSB scalefactor in all g ranges) Patent pending, embedded memory management system with FIFO technology minimizes host processor load Single tap/double tap detection Activity/inactivity monitoring Free-fall detection Supply voltage range: 2.0 V to 3.6 V I/O voltage range: 1.7 V to VS SPI (3- and 4-wire) and I2C digital interfaces Flexible interrupt modes mappable to either interrupt pin Measurement rangesselectable via serial command Bandwidth selectable via serial command Wide temperature range (−40°C to +85°C) 10,000 g shock survival Pb free/RoHS compliant Small and thin: 3 mm × 5 mm × 1 mm LGA package

GENERAL DESCRIPTION
The ADXL345 is a small, thin, ultralow power, 3-axis accelerometer with high resolution (13-bit) measurement at up to ±16 g. Digital output data is formatted as 16-bit twoscomplement and is accessible through either a SPI (3- or 4-wire) or I2C digital interface. The ADXL345 is well suited for mobile device applications. It measures the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration resulting from motion or shock. Its high resolution (3.9 mg/LSB) enables measurement of inclination changes less than 1.0°. Several specialsensing functions are provided. Activity and inactivity sensing detect the presence or lack of motion by comparing the acceleration on any axis with user-set thresholds. Tap sensing detects single and double taps in any direction. Freefall sensing detects if the device is falling. These functions can be mapped individually to either of two interrupt output pins. An integrated, patent pending memorymanagement system with a 32-level first in, first out (FIFO) buffer can be used to store data to minimize host processor activity and lower overall system power consumption. Low power modes enable intelligent motion-based power management with threshold sensing and active acceleration measurement at extremely low power dissipation. The ADXL345 is supplied in a small, thin, 3 mm × 5 mm × 1 mm,14-lead, plastic package.

APPLICATIONS
Handsets Medical instrumentation Gaming and pointing devices Industrial instrumentation Personal navigation devices Hard disk drive (HDD) protection

FUNCTIONAL BLOCK DIAGRAM
VS

VDD I/O

ADXL345

POWER MANAGEMENT

3-AXIS SENSOR

SENSE ELECTRONICS

ADC

DIGITAL FILTER

CONTROL AND INTERRUPT LOGIC

INT1 INT2

32 LEVEL FIFOSDA/SDI/SDIO SERIAL I/O SDO/ALT ADDRESS
07925-001

SCL/SCLK GND CS

Figure 1.
Rev. C
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ADXL345 TABLE OFCONTENTS
Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1...