ADXL05

–5–

REV. B

Polarity of the Acceleration Output

The polarity of the ADXL05 output is shown in the Figure 1.

When oriented to the earth’s gravity (and held in place), the

ADXL05 will experience an acceleration of +1 g. This corre-

put pin. Note that the polarity will be reversed to a negative

inverting configuration.

+1g

INDICATED POLARITY IS THAT

OCCURRING AT V

TAB

PIN 5

+

–

Acceleration Vectors in Three Dimensions

The ADXL05 is a sensor designed to measure accelerations that

result from an applied force. The ADXL05 responds to the

component of acceleration on its sensitive X axis. Figures 2a

and 2b show the relationship between the sensitive “X” axis and

the transverse “Z” and “Y” axes as they relate to the TO-100

Z

Z

X

TRANSVERSE Z AXIS

SENSITIVE (X) AXIS

SIDE VIEW

X

TAB

PIN 5

Figure 2a. Sensitive X and Transverse Z Axis

TRANSVERSE Y AXIS

TOP VIEW

Y

X

Y

SENSITIVE (X) AXIS

X

TAB

PIN 5

Figure 2b. Sensitive X and Transverse Y Axis

GLOSSARY OF TERMS

Acceleration: Change in velocity per unit time.

Acceleration Vector: Vector describing the net acceleration

g: A unit of acceleration equal to the average force of gravity

occurring at the earth’s surface. A g is approximately equal to

32.17 feet/s

Nonlinearity: The maximum deviation of the ADXL05 output

voltage from a best fit straight line fitted to a plot of acceleration

vs. output voltage, calculated as a % of the full-scale output

voltage (@ 5 g).

Resonant Frequency: The natural frequency of vibration of

the ADXL05 sensor’s central plate (or “beam”). At its resonant

frequency of 12 kHz, the ADXL05’s moving center plate has a

peak in its frequency response with a Q of 3 or 4.

Sensitivity: The output voltage change per g unit of accelera-

Sensitive Axis (X): The most sensitive axis of the accelerom-

eter sensor. Defined by a line drawn between the package tab

and Pin 5 in the plane of the pin circle. See Figures 2a and 2b.

Sensor Alignment Error: Misalignment between the

ADXL05’s on-chip sensor and the package axis, defined by

Pin 5 and the package tab.

Total Alignment Error: Net misalignment of the ADXL05’s

on-chip sensor and the measurement axis of the application.

This error includes errors due to sensor die alignment to the

package, and any misalignment due to installation of the sensor

package in a circuit board or module.

Transverse Acceleration: Any acceleration applied 90

° to the

axis of sensitivity.

Transverse Sensitivity Error: The percent of a transverse ac-

transverse sensitivity is 1%, then a +10 g transverse acceleration

verse sensitivity can result from a sensitivity of the sensor to

transverse forces or from misalignment of the internal sensor to

its package.

Transverse Y Axis: The axis perpendicular (90

°) to the pack-

age axis of sensitivity in the plane of the package pin circle. See

Figure 2.

Transverse Z Axis: The axis perpendicular (90

°) to both the

package axis of sensitivity and the plane of the package pin

circle. See Figure 2.