ADXL345

Part: ADXL345 (Analog Devices)

Type: 3-Axis Digital Accelerometer

Key Specs:

• Ultralow power: 23 µA in measurement mode, 0.1 µA in standby mode at V^S = 2.5 V
• Supply voltage range: 2.0 V to 3.6 V
• I/O voltage range: 1.7 V to V^S
• Measurement ranges: ±2 g, ±4 g, ±8 g, ±16 g
• Resolution: Fixed 10-bit, up to 13-bit at ±16 g
• Temperature range: −40°C to +85°C
• Shock survival: 10,000 g

Features:

• Power consumption scales automatically with bandwidth
• User-selectable resolution
• Embedded memory management system with FIFO technology
• Single tap/double tap detection
• Activity/inactivity monitoring
• Free-fall detection
• SPI (3- and 4-wire) and I2C digital interfaces
• Flexible interrupt modes mappable to either interrupt pin
• Measurement ranges selectable via serial command
• Bandwidth selectable via serial command
• Pb free/RoHS compliant

Applications:

• Handsets
• Medical instrumentation
• Gaming and pointing devices
• Industrial instrumentation
• Personal navigation devices
• Hard disk drive (HDD) protection
• Tilt-sensing applications

Package:

• LGA package: 3 mm × 5 mm × 1 mm, 14-lead plastic

• ► Ultralow power: as low as 23 µA in measurement mode and 0.1 µA in standby mode at V^S = 2.5 V (typical)
• ► Power consumption scales automatically with bandwidth
• ► User-selectable resolution
  • ► Fixed 10-bit resolution
  • ► Full resolution, where resolution increases with g range, up to 13-bit resolution at ±16 g (maintaining 4 mg/LSB scale factor in all g ranges*)*
• ► Embedded memory management system with FIFO technology minimizes host processor load
• ► Single tap/double tap detection
• ► Activity/inactivity monitoring
• ► Free-fall detection
• ► Supply voltage range: 2.0 V to 3.6 V
• ► I/O voltage range: 1.7 V to V^S
• ► SPI (3- and 4-wire) and I2C digital interfaces
• ► Flexible interrupt modes mappable to either interrupt pin
• ► Measurement ranges selectable via serial command
• ► Bandwidth selectable via serial command
• ► Wide temperature range (−40°C to +85°C)
• ► 10,000 g shock survival
• ► Pb free/RoHS compliant
• ► Small and thin: 3 mm × 5 mm × 1 mm LGA package

• ► Handsets

• ► Medical instrumentation

• ► Gaming and pointing devices

• ► Industrial instrumentation

• ► Personal navigation devices

• ► Hard disk drive (HDD) protection

GENERAL DESCRIPTION

The ADXL345 is a small, thin, ultralow power, 3-axis accelerometer with high resolution (13-bit) measurement at 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.

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 (3.9 mg/LSB) enables measurement of inclination changes less than 1.0°.

Several special sensing functions are provided. Activity and inactivity sensing detect the presence or lack of motion by comparing the acceleration on any axis with user-set thresholds. Tap sensing detects single and double taps in any direction. Free-fall sensing detects if the device is falling. These functions can be mapped individually to either of two interrupt output pins. An integrated memory management system with a 32-level first in, first out (FIFO) buffer can be used to store data to minimize host processor activity and lower overall system power consumption.

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.

Figure 3. Pin Configuration (Top View)

Table 5. Pin Function Descriptions

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Table 2.

Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability.

Table 3. Package Characteristics