3-Axis, 1.5 g/3 g/6 g/12 g Digital Accelerometer Data Sheet ADXL312 FEATURES GENERAL DESCRIPTION 1 Ultralow power: as low as 57 A in measurement mode and The ADXL312 is a small, thin, low power, 3-axis accelerometer 0.1 A in standby mode at V = 3.3 V (typical) S with high resolution (13-bit) measurement up to 12 g. Digital Power consumption scales automatically with bandwidth output data is formatted as 16-bit twos complement and is User-selectable resolution accessible through either a serial port interface (SPI) (3- or 4-wire) 2 Fixed 10-bit resolution or I C digital interface. Full resolution, where resolution increases with g range, The ADXL312 is well suited for car alarm or black box applica- up to 13-bit resolution at 12 g (maintaining 2.9 mg/LSB tions. It measures the static acceleration of gravity in tilt-sensing scale factor in all g ranges) applications, as well as dynamic acceleration resulting from motion Embedded FIFO technology minimizes host processor load or shock. Its high resolution (2.9 mg/LSB) enables resolution of Built-in motion detection functions for activity/inactivity inclination changes of as little as 0.25. A built-in FIFO facili- monitoring tates using oversampling techniques to improve resolution to as Supply and I/O voltage range: 2.0 V to 3.6 V little as 0.05 of inclination. 2 SPI (3- and 4-wire) and I C digital interfaces Several special sensing functions are provided. Activity and Flexible interrupt modes mappable to either interrupt pin inactivity sensing detects the presence or absence of motion and Measurement ranges selectable via serial command whether the acceleration on any axis exceeds a user-set level. Bandwidth selectable via serial command These functions can be mapped to interrupt output pins. An Wide temperature range (40 to +105C) integrated 32 level FIFO can be used to store data to minimize 10,000 g shock survival host processor intervention. Pb free/RoHS compliant Small and thin: 5 mm 5 mm 1.45 mm LFCSP package Low power modes enable intelligent motion-based power Qualified for automotive applications management with threshold sensing and active acceleration measurement at extremely low power dissipation. APPLICATIONS Car alarm The ADXL312 is supplied in a small, thin 5 mm 5 mm Hill start aid (HSA) 1.45 mm, 32-lead, LFCSP package. Electronic parking brake Data recorder (black box) FUNCTIONAL BLOCK DIAGRAM V V S DD I/O ADXL312 POWER MANAGEMENT INT1 CONTROL SENSE ADC AND 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. ADXL312 Simplified Block Diagram 1 Protected by U.S. Patent 8,156,264B2. Rev. B 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. 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Technical Support www.analog.com 08791-001ADXL312 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 FIFO ............................................................................................. 18 Applications ....................................................................................... 1 Self-Test ....................................................................................... 19 General Description ......................................................................... 1 Register Map ................................................................................... 20 Functional Block Diagram .............................................................. 1 Register Definitions ................................................................... 21 Revision History ............................................................................... 2 Applications Information .............................................................. 25 Specifications ..................................................................................... 3 Power Supply Decoupling ......................................................... 25 Absolute Maximum Ratings ............................................................ 5 Mechanical Considerations for Mounting .............................. 25 Thermal Resistance ...................................................................... 5 Threshold .................................................................................... 25 ESD Caution .................................................................................. 5 Link Mode ................................................................................... 25 Pin Configuration and Function Descriptions ............................. 6 Sleep Mode vs. Low Power Mode............................................. 25 Typical Performance Characteristics ............................................. 7 Using Self-Test ............................................................................ 26 Theory of Operation ...................................................................... 10 Data Formatting of Upper Data Rates ..................................... 27 Power Sequencing ...................................................................... 10 Noise Performance ..................................................................... 28 Power Savings.............................................................................. 10 Axes of Acceleration Sensitivity ............................................... 29 Serial Communications ................................................................. 12 Solder Profile ................................................................................... 30 SPI ................................................................................................. 12 Outline Dimensions ....................................................................... 31 2 I C ................................................................................................. 15 Ordering Guide .......................................................................... 32 Interrupts ..................................................................................... 17 Automotive Products ................................................................. 32 REVISION HISTORY 4/2017Rev. A to Rev. B Added Serial Port I/O Default States Section ............................. 12 Changes to Standby Mode Leakage Current Parameter, Table 1 ...... 3 Added Preventing Bus Traffic Errors Section and Figure 23 Updated Outline Dimensions ....................................................... 31 Renumbered Sequentially ............................................................. 13 Changes to Ordering Guide .......................................................... 32 Changes to FIFO Section ............................................................... 18 Changes to Figure 41 ...................................................................... 31 7/2015Rev. 0 to Rev. A 12/2010Revision 0: Initial Version Changes to Features Section............................................................ 1 Changes to Pin 22 Description, Table 4 ......................................... 6 Changes to Serial Communications Section, SPI Section, Figure 21, and Figure 22 ................................................................ 12 Rev. B Page 2 of 32