Three-Axis, ±2/4/8/16g

Digital Accelerometer

Preliminary Technical Data

ADXL345

Rev. PrA

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibilityisassumedbyAnalogDevices for itsuse,nor foranyinfringementsofpatentsor other

rightsofthirdpartiesthatmayresultfromitsuse.Specificationssubjecttochangewithoutnotice.No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarksandregisteredtrademarksarethepropertyoftheirrespectiveowners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.461.3113

©2008 Analog Devices, Inc. All rights reserved.

FEATURES

Power consumption scales automatically with bandwidth

User selectable fixed 10-bit resolution or 4mg/LSB scale

factor in all g-ranges, up to 13-bit resolution at ±16 g

32 level output data FIFO minimizes host processor load

Built in motion detection functions

•

Tap/Double Tap detection

•

Activity/Inactivity monitoring

•

Free-Fall detection

Supply and I/O voltage range: 1.8 V to 3.6 V

Flexible interrupt modes – Any interrupt mappable to either

interrupt pin

Measurement ranges selectable via serial command

Bandwidth selectable via serial command

Wide temperature range (-40 to +85°C)

10,000 g shock survival

Pb free/RoHS compliant

Small and thin: 3 × 5 × 1 mm LGA package

APPLICATIONS

Handsets

Gaming and pointing devices

Personal navigation devices

HDD protection

Fitness equipment

Digital cameras

GENERAL DESCRIPTION

The ADXL345 is a small, thin, low power, three-axis

accelerometer with high resolution (13-bit) measurement up to

±16 g. Digital output data is formatted as 16-bit twos

complement and is accessible through either a SPI (3- or 4-

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 (4mg/LSB) enables

resolution of inclination changes of as little as 0.25°.

Several special sensing functions are provided. Activity and

inactivity sensing detect the presence or lack of motion and if

the acceleration on any axis exceeds a user-set level. Tap sensing

detects single and double taps. Free-Fall sensing detects if the

device is falling. These functions can be mapped to interrupt

output pins. An integrated 32 level FIFO can be used to store

data to minimize host processor intervention.

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.

FUNCTIONAL BLOCK DIAGRAM

Figure 1. ADXL345 Simplified Block Diagram

3 AXIS

SENSOR

DIGITAL

FILTER

SENSE

ELECTRONICS

CONTROL

AND

INTERRUPT

LOGIC

SERIAL I/O

POWER

MANAGEMENT

COM

CS

SCL/SCLK

SDO/ALT

ADDRESS

SDA/SDI/SDIO

INT2

V

Vs

INT1

ADXL345

3 AXIS

SENSOR

DIGITAL

FILTER

DIGITAL

FILTER

SENSE

ELECTRONICS

CONTROL

AND

INTERRUPT

LOGIC

CONTROL

AND

INTERRUPT

LOGIC

SERIAL I/O

SERIAL I/O

POWER

MANAGEMENT

POWER

MANAGEMENT

COM

CS

SCL/SCLK

SDO/ALT

ADDRESS

SDA/SDI/SDIO

INT2

V

Vs

INT1

ADXL345