Datasheet ADXL312 (Analog Devices)

3-Axis, ±1.5 g /±3 g /±6 g /±12 g Digital Accelerometer Data Sheet ADXL312 FEATURES GENERAL DESCRIPTION Ultralow power: as low as 57 µA in measurement mode and
The ADXL3121 is a small, thin, low power, 3-axis accelerometer
0.1 µA in standby mode at VS = 3.3 V (typical)
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)
Fixed 10-bit resolution
or I2C 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.
SPI (3- and 4-wire) and I2C digital interfaces Flexible interrupt modes mappable to either interrupt pin
Several special sensing functions are provided. Activity and
Measurement ranges selectable via serial command
inactivity sensing detects the presence or absence of motion and
Bandwidth selectable via serial command
whether the acceleration on any axis exceeds a user-set level.
Wide temperature range (−40 to +105°C)
These functions can be mapped to interrupt output pins. An
10,000 g shock survival
integrated 32 level FIFO can be used to store data to minimize
Pb free/RoHS compliant
host processor intervention.
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
APPLICATIONS
measurement at extremely low power dissipation.
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 VS VDD I/O ADXL312 POWER MANAGEMENT CONTROL INT1 SENSE ADC AND ELECTRONICS DIGITAL INTERRUPT 3-AXIS FILTER LOGIC INT2 SENSOR SDA/SDI/SDIO 32 LEVEL SERIAL I/O FIFO SDO/ALT ADDRESS SCL/SCLK
001
GND CS
08791- Figure 1. ADXL312 Simplified Block Diagram 1 Protected by U.S. Patent 8,156,264B2.
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Document Outline Features Applications General Description Functional Block Diagram Revision History Specifications Absolute Maximum Ratings Thermal Resistance ESD Caution Pin Configuration and Function Descriptions Typical Performance Characteristics Theory of Operation Power Sequencing Power Savings Power Modes Autosleep Mode Standby Mode Serial Communications Serial Port I/O Default states SPI Preventing Bus Traffic Errors I2C Interrupts DATA_READY Activity Inactivity Watermark Overrun FIFO Bypass Mode FIFO Mode Stream Mode Trigger Mode Retrieving Data from FIFO Self-Test Register Map Register Definitions Register 0x00—DEVID (Read Only) Register 0x1E, Register 0x1F, Register 0x20—OFSX, OFSY, OFSZ (Read/Write) Register 0x24—THRESH_ACT (Read/Write) Register 0x25—THRESH_INACT (Read/Write) Register 0x26—TIME_INACT (Read/Write) Register 0x27—ACT_INACT_CTL (Read/Write) ACT AC/DC and INACT AC/DC Bits ACT_x Enable Bits and INACT_x Enable Bits Register 0x2C—BW_RATE (Read/Write) LOW_POWER Bit Rate Bits Register 0x2D—POWER_CTL (Read/Write) Link Bit AUTO_SLEEP Bit Measure Bit Sleep Bit Wake-Up Bits Register 0x2E—INT_ENABLE (Read/Write) Register 0x2F—INT_MAP (Read/Write) Register 0x30—INT_SOURCE (Read Only) Register 0x31—DATA_FORMAT (Read/Write) SELF_TEST Bit SPI Bit INT_INVERT Bit FULL_RES Bit Justify Bit Range Bits Register 0x32 to Register 0x37—DATAX0, DATAX1, DATAY0, DATAY1, DATAZ0, DATAZ1 (Read Only) Register 0x38—FIFO_CTL (Read/Write) FIFO_MODE Bits Trigger Bit Samples Bits 0x39—FIFO_STATUS (Read Only) FIFO_TRIG Bit Entries Bits Applications Information Power Supply Decoupling Mechanical Considerations for Mounting Threshold Link Mode Sleep Mode vs. Low Power Mode Using Self-Test Data Formatting of Upper Data Rates Noise Performance Axes of Acceleration Sensitivity Solder Profile Outline Dimensions Ordering Guide Automotive Products