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DE-ACCM2G2 Buffered ±2g Accelerometer

Features

Dual axis ±2g sense range

660mV/g sensitivity

500Hz bandwidth

Operating voltage 3.5V to 15V (onboard regulator)

Reverse voltage protection

Overvoltage protected up to 14V

Output short protection

Standard DIP-14 form factor

Integrated power supply decoupling

Draws under 2mA

<4% typical 0g bias deviation from Vcc/2

Shiny gold pins to distract the enemy!

Applications

Motion, tilt and slope measurement

Shock sensing

Vehicle acceleration logging

General Description

The DE-ACCM2G2 is an off the shelf 2 axis 2g

accelerometer solution with analog outputs. It

features integrated op amp buffers for direct

connection to a microcontroller’s analog

inputs, or for driving heavier loads.

Additional circuitry ensures that the product

won’t be damaged by reversed power

connections, or voltages above the

recommended ratings.

The DE-ACCM2G2 is designed to fit the DIP-

14 form factor, making it suitable for

breadboarding, perfboarding, and insertion

into standard chip sockets.

It is based on the ST MicroElectronics

LIS244ALH for superior sensitivity and lower

cost.

Summary of content (4 pages)

PAGE 1
DE-ACCM2G2 Buffered ±2g Accelerometer General Description The DE-ACCM2G2 is an off the shelf 2 axis 2g accelerometer solution with analog outputs. It features integrated op amp buffers for direct connection to a microcontroller’s analog inputs, or for driving heavier loads. Additional circuitry ensures that the product won’t be damaged by reversed power connections, or voltages above the recommended ratings.
PAGE 2
Measuring acceleration and tilt The voltage outputs on the DE-ACCM2G correspond to acceleration being experienced in the X and Y directions. The output is ratiometric, so the output sensitivity (in mV/g) depends on the supply voltage. The onboard regulator of the DE-ACCM2G2 keeps a constant 3.3V, making sensitivity a consistent 660mV/g. Zero acceleration (0g) will result in an output of Vcc/2.
PAGE 3
Voltage to acceleration example: ”The X output reads 2.14V. What acceleration does this correspond to?” The 0g point is approximately Vcc / 2 = 3.3 / 2 = 1.65V 2.14V – 1.65V = +0.49V with respect to the 0g point If sensitivity is 660mV/g, 0.49 / 0.660 = 0.742g Therefore the acceleration in the X direction is +0.742g Acceleration to voltage example: ”What voltage will correspond to an acceleration of -0.5g?” The 0g point is approximately 1.65V If sensitivity is 660mV/g, -0.5 * 0.660 = -0.
PAGE 4
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-ACCM2G, a dual rail to rail operational amplifier buffers the outputs from the LIS244ALH, greatly reducing output impedance. Supply filtering A pair of resistors and a 0.1uF ceramic bypass capacitor on the DE-ACCM2G2 provide excellent power supply decoupling.