3-Axis, 2 g/4 g/8 g/16 g Digital Accelerometer Data Sheet ADXL345 FEATURES GENERAL DESCRIPTION Ultralow power: as low as 23 A in measurement mode and The ADXL345 is a small, thin, ultralow power, 3-axis accelerometer 0.1 A in standby mode at V = 2.5 V (typical) S with high resolution (13-bit) measurement at up to 16 g. Digital Power consumption scales automatically with bandwidth output data is formatted as 16-bit twos complement and is acces- 2 User-selectable resolution sible through either a SPI (3- or 4-wire) or I C digital interface. Fixed 10-bit resolution The ADXL345 is well suited for mobile device applications. It Full resolution, where resolution increases with g range, measures the static acceleration of gravity in tilt-sensing appli- up to 13-bit resolution at 16 g (maintaining 4 mg/LSB cations, as well as dynamic acceleration resulting from motion scale factor in all g ranges) or shock. Its high resolution (3.9 mg/LSB) enables measurement Embedded memory management system with FIFO of inclination changes less than 1.0. technology minimizes host processor load Several special sensing functions are provided. Activity and Single tap/double tap detection inactivity sensing detect the presence or lack of motion by Activity/inactivity monitoring comparing the acceleration on any axis with user-set thresholds. Free-fall detection Tap sensing detects single and double taps in any direction. Free- Supply voltage range: 2.0 V to 3.6 V fall sensing detects if the device is falling. These functions can I/O voltage range: 1.7 V to V S 2 be mapped individually to either of two interrupt output pins. SPI (3- and 4-wire) and I C digital interfaces An integrated memory management system with a 32-level first in, Flexible interrupt modes mappable to either interrupt pin first out (FIFO) buffer can be used to store data to minimize host Measurement ranges selectable via serial command processor activity and lower overall system power consumption. Bandwidth selectable via serial command Wide temperature range (40C to +85C) Low power modes enable intelligent motion-based power 10,000 g shock survival management with threshold sensing and active acceleration Pb free/RoHS compliant measurement at extremely low power dissipation. Small and thin: 3 mm 5 mm 1 mm LGA package The ADXL345 is supplied in a small, thin, 3 mm 5 mm 1 mm, APPLICATIONS 14-lead, plastic package. Handsets Medical instrumentation Gaming and pointing devices Industrial instrumentation Personal navigation devices Hard disk drive (HDD) protection FUNCTIONAL BLOCK DIAGRAM V V S DD I/O ADXL345 POWER MANAGEMENT INT1 CONTROL SENSE AND ADC DIGITAL ELECTRONICS INTERRUPT FILTER 3-AXIS LOGIC INT2 SENSOR SDA/SDI/SDIO 32 LEVEL SERIAL I/O FIFO SDO/ALT ADDRESS SCL/SCLK GND CS Figure 1. Rev. E Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 20092015 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Technical Support www.analog.com Trademarks and registered trademarks are the property of their respective owners. 07925-001ADXL345 Data Sheet TABLE OF CONTENTS Self-Test ....................................................................................... 22 Features .............................................................................................. 1 Register Map ................................................................................... 23 Applications ....................................................................................... 1 Register Definitions ................................................................... 24 General Description ......................................................................... 1 Applications Information .............................................................. 28 Functional Block Diagram .............................................................. 1 Power Supply Decoupling ......................................................... 28 Revision History ............................................................................... 3 Mechanical Considerations for Mounting .............................. 28 Specifications ..................................................................................... 4 Tap Detection .............................................................................. 28 Absolute Maximum Ratings ............................................................ 6 Threshold .................................................................................... 29 Thermal Resistance ...................................................................... 6 Link Mode ................................................................................... 29 Package Information .................................................................... 6 Sleep Mode vs. Low Power Mode............................................. 30 ESD Caution .................................................................................. 6 Offset Calibration ....................................................................... 30 Pin Configuration and Function Descriptions ............................. 7 Using Self-Test ............................................................................ 31 Typical Performance Characteristics ............................................. 8 Data Formatting of Upper Data Rates ..................................... 32 Theory of Operation ...................................................................... 13 Noise Performance ..................................................................... 33 Power Sequencing ...................................................................... 13 Operation at Voltages Other Than 2.5 V ................................ 33 Power Savings ............................................................................. 14 Offset Performance at Lowest Data Rates ............................... 34 Serial Communications ................................................................. 15 Axes of Acceleration Sensitivity ............................................... 35 SPI ................................................................................................. 15 2 Layout and Design Recommendations ................................... 36 I C ................................................................................................. 18 Outline Dimensions ....................................................................... 37 Interrupts ..................................................................................... 20 Ordering Guide .......................................................................... 37 FIFO ............................................................................................. 21 Rev. E Page 2 of 40