ADXL345

Preliminary Technical Data FEATURES Ultra low power: 25 to 130 µA at VS = 2.5 V (typ) 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 SPI (3 and 4 wire) and I2C digital interfaces 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 Three-Axis, ±2/4/8/16g Digital Accelerometer ADXL345 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 4wire) 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 (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. APPLICATIONS Handsets Gaming and pointing devices Personal navigation devices HDD protection Fitness equipment Digital cameras FUNCTIONAL BLOCK DIAGRAM Vs VDD I/O POWER MANAGEMENT A/D CONVERTER 3 AXIS AXIS SENSOR SENSE ELECTRONICS DIGITAL FILTER CONTROL AND INTERRUPT LOGIC INT1 INT2 SDA/SDI/SDIO ADXL345 SERIAL I/O SDO/ALT ADDRESS SCL/SCLK COM CS Figure 1. ADXL345 Simplified Block Diagram Rev. PrA 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 rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. 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. ADXL345 TABLE OF CONTENTS Features .............................................................................................. 1 Applications....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 4 ESD Caution.................................................................................. 4 Pin Configuration and Descriptions.............................................. 5 Typical performance characteristics .............................................. 6 Functional Description .................................................................... 7 Device Operation ......................................................................... 7 Power Sequencing ........................................................................ 7 Power Saving ................................................................................. 7 Serial Communications ................................................................... 9 SPI................................................................................................... 9 Preliminary Technical Data I2C................................................................................................. 10 Interrupts..................................................................................... 11 FIFO ............................................................................................. 11 Self Test ........................................................................................ 12 Register Map ................................................................................... 13 Register Definitions ................................................................... 14 Application ...................................................................................... 18 Power Supply Decoupling ......................................................... 18 Mechanical Considerations for Mounting.............................. 18 Tap Detection.............................................................................. 18 Threshold .................................................................................... 19 Link Mode ................................................................................... 19 Recommended PWB Land Pattern.......................................... 20 Recommended Soldering Profile ............................................. 21 Outline Dimensions ....................................................................... 22 Ordering Guide .......................................................................... 22 REVISION HISTORY 11/08—Rev. PrA - Initial Version Rev. PrA | Page 2 of 24 Preliminary Technical Data SPECIFICATIONS TA = 25°C, VS = 2.5 V, VDD I/O = 1.8 V, Acceleration = 0 g, unless otherwise noted. Table 1. Specifications1 Parameter SENSOR INPUT Measurement Range Nonlinearity Inter-Axis Alignment Error Cross-Axis Sensitivity2 OUTPUT RESOLUTION All g-ranges ±2 g range ±4 g range ±8 g range ±16 g range SENSITIVITY Sensitivity at XOUT, YOUT, ZOUT Scale Factor at XOUT, YOUT, ZOUT Sensitivity at XOUT, YOUT, ZOUT Scale Factor at XOUT, YOUT, ZOUT Sensitivity at XOUT, YOUT, ZOUT Scale Factor at XOUT, YOUT, ZOUT Sensitivity at XOUT, YOUT, ZOUT Scale Factor at XOUT, YOUT, ZOUT Sensitivity Change due to Temperature 0 g BIAS LEVEL 0 g Output (XOUT, YOUT, ZOUT) 0 g Offset vs. Temperature NOISE PERFORMANCE Noise (x-, y-axes) Noise (z-axis) OUTPUT DATA RATE / BANDWIDTH Measurement Rate3 SELF TEST Output Change X Output Change Y Output Change Z POWER SUPPLY Operating Voltage Range (VS) Interface Voltage Range (VDD I/O) Supply Current Supply Current Standby Mode Leakage Current Turn-On Time4 TEMPERATURE Operating Temperature Range WEIGHT Device Weight 1 2 ADXL345 Conditions Each axis User Selectable Percentage of full scale Min Typ ±2, 4, 8, 16 ±0.5 ±0.1 ±1 10 10 11 12 13 Max Unit g % Degrees % Bits Bits Bits Bits Bits Each axis 10-bit mode Full-Resolution Full-Resolution Full-Resolution Full-Resolution Each axis VS = 2.5 V, ±2 g 10-bit or Full-Resolution VS = 2.5 V, ±2 g 10-bit or Full-Resolution VS = 2.5 V, ±4 g 10-bit mode VS = 2.5 V, ±4 g 10-bit mode VS = 2.5 V, ±8 g 10-bit mode VS = 2.5 V, ±8 g 10-bit mode VS = 2.5 V, ±16 g 10-bit mode VS = 2.5 V, ±16 g 10-bit mode Each axis VS = 2.5 V, TA = 25°C 232 3.5 116 7.0 58 14.0 29 28.1 256 3.9 128 7.8 64 15.6 32 31.2 ±0.02 0 0x10, and THRESH_TAP>3g. Setting very low values in the L ATENT, WINDOW, and/or THRESH_TAP registers may result in unpredictable response due to the accelerometer picking up “echoes” of the tap inputs. After a tap interrupt is received, the first axis to exceed the THRESH_TAP level is reported in the ACT_TAP_STATUS register. This register is never cleared, but overwritten with new data. Rev. PrA | Page 19 of 24 ADXL345 RECOMMENDED PWB LAND PATTERN 3.3400 1.0500 Preliminary Technical Data 0.5500 0.2500 3.0500 0.3400 5.34 0.2500 1.1450 Figure 14. Recommended Printed Wiring Board Land Pattern (Dimensions Shown in Millimeters) Rev. PrA | Page 20 of 24 06238-015 Preliminary Technical Data RECOMMENDED SOLDERING PROFILE TP RAMP-UP ADXL345 tP CRITICAL ZONE TL TO TP TEMPERATURE TL TSMAX TSMIN tL tS PREHEAT RAMP-DOWN t25°C TO PEAK TIME Figure 15. Recommended Soldering Profile Table 17. Recommended Soldering Profile1 Profile Feature Average Ramp Rate (TL to TP) Preheat Minimum Temperature (TSMIN) Maximum Temperature (TSMAX) Time (TSMIN to TSMAX)(tS) TSMAX to TL Ramp-Up Rate Time Maintained Above Liquidous (TL) Liquidous Temperature (TL) Time (tL) Peak Temperature (TP) Time Within 5°C of Actual Peak Temperature (tP) Ramp-Down Rate Time 25°C to Peak Temperature Sn63/Pb37 3°C/sec max 100°C 150°C 60 sec to 120 sec 3°C/sec max 183°C 60 sec to 150 sec 240 + 0/−5°C 10 sec to 30 sec 6°C/sec max 6 minutes max Condition Pb-Free 3°C/sec max 150°C 200°C 60 sec to 180 sec 3°C/sec max 217°C 60 sec to 150 sec 260 + 0/−5°C 20 sec to 40 sec 6°C/sec max 8 minutes max Rev. PrA | Page 21 of 24 06238-016 ADXL345 OUTLINE DIMENSIONS Preliminary Technical Data 1 Figure 35. 14-Lead Land Grid Array Package [LGA] 3 mm × 5 mm Body, Thick Quad Dimensions shown in millimeters Lead finish: matte tin ORDERING GUIDE Model ADXL345BCCZ1 ADXL345BCCZ–RL1 ADXL345BCCZ–RL71 EVAL-ADXL345Z1 1 Measurement Range ±2, 4, 8, 16g ±2, 4, 8, 16g ±2, 4, 8, 16g Specified Voltage (V) 2.5 2.5 2.5 Temperature Range −40°C to +85°C −40°C to +85°C −40°C to +85°C Package Description 14-Lead Land Grid Array Package [LGA] 14-Lead Land Grid Array Package [LGA] 14-Lead Land Grid Array Package [LGA] Evaluation Board Package Option TBD TBD TBD Z = Pb-free part. Rev. PrA | Page 22 of 24 Preliminary Technical Data NOTES ADXL345 Rev. PrA | Page 23 of 24 ADXL345 NOTES Preliminary Technical Data ©2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR07925-0-11/08(PrA) Rev. PrA | Page 24 of 24