DE-ACCM3D Datasheet, PDF (4/5 Pages) List of Unclassifed Manufacturers – Buffered ±3g Tri-axis Accelerometer

Performance features
Output buffers
A bare accelerometer chip has an output impedance of 32kΩ, which is unsuitable for obtaining reliable
measurements when connected to an analog to digital converter. On the DE-ACCM3D, a quad rail to rail
operational amplifier buffers the outputs from the ADXL330, greatly reducing output impedance. The
absolute maximum load beyond which accuracy begins to seriously suffer is 3.3mA, or 500Ω.
Supply filtering
A 1uF ceramic bypass capacitor on the DE-ACCM3D provides excellent power supply decoupling. No
external capacitors are necessary between Vcc and GND.
Output filtering and noise
A pair of 10nF capacitors limit the noise figure of the DE-ACCM3D, without overly sacrificing bandwidth.
RMS noise is typically 7.3mg, and output bandwidth is 500Hz - making it suitable for high frequency
sampling of acceleration.
Regulator Bypass
Most people will want to power DE-ACCM3D using the onboard 3.3V regulator. However, if you are
designing an application that needs a lower operating voltage, you can bypass the voltage regulator.
To do this, use the GND pin as normal. For the positive supply, solder a wire to the exposed pad labeled
BYP. The onboard 1uF capacitor will still be in parallel with the accelerometer chip, so additional capacitance
is not necessary unless running from a noisy source.
This would be useful for e.g. an application powered directly by 2 AA batteries or a lithium coin battery.
The minimum operating voltage when using bypass mode is 2.0V and the absolute maximum
voltage that can be applied when bypassing the regulator is 3.6V.