Three-Axis, 2/4/8/16g
Digital Accelerometer
ADXL345
Preliminary Technical Data
FEATURES
GENERAL DESCRIPTION
Ultra low power: 25 to 130 µA at VS = 2.5 V (typ)
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-
wire) or I2C digital interface.
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
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°.
•
•
•
Tap/Double Tap detection
Activity/Inactivity monitoring
Free-Fall detection
Supply and I/O voltage range: 1.8 V to 3.6 V
SPI (3 and 4 wire) and I2C digital interfaces
Flexible interrupt modes – Any interrupt mappable to either
interrupt pin
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.
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
Low power modes enable intelligent motion-based power
management with threshold sensing and active acceleration
measurement at extremely low power dissipation.
APPLICATIONS
Handsets
Gaming and pointing devices
Personal navigation devices
HDD protection
The ADXL345 is supplied in a small, thin 3 mm × 5 mm ×
1 mm, 14-lead, plastic package.
Fitness equipment
Digital cameras
FUNCTIONAL BLOCK DIAGRAM
Vs
VDD I/O
POWER
MANAGEMENT
INT1
INT2
CONTROL
AND
INTERRUPT
LOGIC
SENSE
DIGITAL
FILTER
ELECTRONICS
3 AXIS
SENSOR
SDA/SDI/SDIO
SERIAL I/O
ADXL345
SDO/ALT
ADDRESS
SCL/SCLK
COM
CS
Figure 1. ADXL345 Simplified Block Diagram
Rev. PrA
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