Low Cost ±1.2 Dual Axis Accelerometer

The ADXL213 is a low cost, low power, complete dual axis accelerometer with signal conditioned, duty cycle modulated outputs, all on a single monolithic IC. The ADXL213 measures acceleration with a full-scale range of ±1.2 g (typical). The ADXL213 can measure both dynamic acceleration (e.g., vibration) and static acceleration (e.g., gravity).

The outputs are digital signals whose duty cycles (ratio of pulse width to period) are proportional to acceleration (30%/g). The duty cycle outputs can be directly measured by a microcontroller without an A/D converter or glue logic.

Innovative design techniques are used to ensure high zero g bias stability (typically better than 0.25 mg/°C), as well as tight sensitivity stability (typically better than 50 ppm/°C).

The typical noise floor is 160 μg/√, allowing signals below 1 mg (0.06° of inclination) to be resolved in tilt sensing applications using narrow bandwidths (<60 Hz).

The user selects the bandwidth of the accelerometer using capacitors CX and CYM at the XFILT and YFILT pins. Bandwidths of 0.5 Hz to 250 Hz may be selected to suit the application.

The ADXL213 is available in a 5mm x 5mm x 2mm, 8-pad hermetic LCC package.

Applications

* Automotive tilt alarm

* Data projectors

* Navigation

* Platform stabilization/leveling

* Alarms and motion detectors

* High accuracy, 2-axis tilt sensing

* Dual axis accelerometer on a single IC chip * 5 mm × 5 mm × 2 mm LCC package * 1 mg resolution at 60 Hz * Low power: 700 µA at Vs = 5 V (typical) * High zero g bias stability