ADXL345 accelerometer: specs and pinout
Digital 3-axis accelerometer with selectable ±2 g to ±16 g ranges and I2C or SPI interfaces.
Specs
| Spec | Value | Source |
|---|---|---|
| Supply voltage (VS) | 2.0 V to 3.6 V | source Features |
| I/O voltage range | 1.7 V to VS | source Features |
| Measurement range | ±2 g, ±4 g, ±8 g, ±16 g (selectable) | source Specifications, sensitivity table |
| Resolution | Fixed 10-bit, or full resolution up to 13-bit at ±16 g with 4 mg/LSB scale factor in all g ranges | source Features, user-selectable resolution |
| Output data rate | 6.25 Hz to 3200 Hz | source Specifications, output data rate range |
| Interface | SPI (3-wire and 4-wire) and I2C | source Features |
| SPI clock frequency | 5 MHz maximum | source SPI digital interface timing table (fSCLK) |
| I2C address | 0x1D when SDO/ALT ADDRESS is high; 0x53 when it is grounded | source I2C digital interface section |
| Zero-g bias level | ±40 mg (data rate 100 Hz, ±2 g, 10-bit or full resolution) | source Specifications, 0 g bias level |
| Operating temperature | -40 °C to +85 °C | source Features; specifications |
Power
| Value | Source | |
|---|---|---|
| Supply | VS 2.0 V to 3.6 V; VDD I/O 1.7 V to VS | source Features; Table 6 (current consumption vs data rate) |
| Current | As low as 40 µA in measurement mode; 0.1 µA standby (typical), VS = 2.5 V. Table 6 gives 40 µA to 145 µA by output data rate. | source Features; Table 6 (current consumption vs data rate) |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently. Module header labels (VCC, GND, SDA, SCL…) come from the Compoden listing, not an official module schematic.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| VDD I/O (pin 1) | Digital interface supply voltage | 1.7 V to VS | Must not exceed VS or 3.6 V (absolute maximum) | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) |
| GND (pin 2) | Ground (must be connected to ground) | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| Reserved (pin 3) | Reserved: connect to VS or leave open | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| GND (pin 4) | Ground (must be connected to ground) | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| GND (pin 5) | Ground (must be connected to ground) | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| VS (pin 6) | Supply voltage | 2.0 V to 3.6 V | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | |
| CS (pin 7) | Chip select | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | High selects I2C mode | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) |
| INT1 (pin 8) | Interrupt 1 output | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | |
| INT2 (pin 9) | Interrupt 2 output | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | |
| NC (pin 10) | Not internally connected | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| Reserved (pin 11) | Reserved: connect to ground or leave open | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | ||
| SDO / ALT ADDRESS (pin 12) | Serial data output (SPI) / alternate I2C address select | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | I2C address 0x1D when high, 0x53 when grounded | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) |
| SDA / SDI / SDIO (pin 13) | Serial data (I2C) / serial data input (SPI 4-wire) / serial data input and output (SPI 3-wire) | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) | |
| SCL / SCLK (pin 14) | Serial communications clock | 3.6 V max (digital pins absolute maximum -0.3 V to +3.6 V); not 5 V tolerant | source Pin Configuration and Function Descriptions, Table 4 (datasheet Rev. 0 page 5) |
Common mistakes
- Setting the I/O supply above VS: the I/O voltage range is 1.7 V to VS (source)
- Assuming address 0x53 without checking the SDO/ALT ADDRESS pin: high gives 0x1D and grounded gives 0x53 (source)
- Using 3.9 mg/LSB as the scale factor for ±16 g: the datasheet states 4 mg/LSB in all g ranges at full resolution (source)
What we could not confirm
- The datasheet used is ADI Rev. 0 (initial 2009 version). Newer ADI revisions are not covered, so confirm values against the current one.
- I2C maximum clock is not stated in the datasheet, so a 3.4 MHz figure is not given.
- Draft's minimum output data rate of 0.1 Hz was not found in Rev. 0. 6.25 Hz is used.
- The datasheet gives no single accuracy figure. The zero-g bias row is the closest figure.
- Pin rows are the ADXL345 chip's 14 pins (datasheet Rev. 0). Which chip pin each module header label connects to (and any level shifting or regulator on the module) is not from an official source.
Sources
- Analog Devices ADXL345 datasheet, Rev. 0 (official URL: link).
- Copy of the Analog Devices Rev. 0 datasheet hosted by a hosted copy (sparkfun.com/datasheets/Sensors/Accelerometer/ADXL345.pdf).
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