Analog Devices ADXL311 B Datasheet

Ultracompact ±2g Dual-Axis Accelerometer

FEATURES

High resolution
Dual-axis accelerometer on a single IC chip
5 mm × 5 mm × 2 mm LCC package
Low power <400 µA (typ)
X-axis and Y-axis aligned to within 0.1° (typ)
BW adjustment with a single capacitor
Single-supply operation
High shock survival

APPLICATIONS

Tilt and motion sensing
Smart hand-held devices
Computer security
Input devices
Pedometers and activity monitors
Game controllers
Toys and entertainment products

GENERAL DESCRIPTION

The ADXL311 is a low power, complete dual-axis accelerometer
with signal conditioned voltage outputs, all on a single
monolithic IC. The ADXL311 is built using the same proven
iMEMS® process used in over 180 million Analog Devices
accelerometers shipped to date, with demonstrated 1 FIT
reliability (1 failure per 1 billion device operating hours).

The ADXL311 measures acceleration with a full-scale range of
±2 g. The ADXL311 can measure both dynamic acceleration
(e.g., vibration) and static acceleration (e.g., gravity). The
outputs are analog voltages proportional to acceleration.

ADXL311

FUNCTIONAL BLOCK DIAGRAM

3.0V
V

DD

X SENSOR

DEMOD

CDC

OSCILLATOR

DEMOD

Y SENSOR

COM Y

The typical noise floor is 300 µg/√
2 mg (0.1° of inclination) to be resolved in tilt sensing appli-

cations using narrow bandwidths (10 Hz).

The user selects the bandwidth of the accelerometer using
capacitors C

and CY at the X

X

of 1 Hz to 3 kHz can be selected to suit the application.

The ADXL311 is available in a 5 mm × 5 mm × 2 mm,
8-terminal, hermetic LCC package.

C

X

FILT

32kΩ

Y

FILT

32kΩ

OUT

Figure 1.

and Y

OUT

X

X

OUT

ADXL311

C

Y

, allowing signals below

Hz

OUT

SELF TEST

pins. Bandwidths

03582-001

Rev. B

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However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
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registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2005 Analog Devices, Inc. All rights reserved.

ADXL311

TABLE OF CONTENTS

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 4

ESD Caution.................................................................................. 4

Pin Configuration and Function Descriptions............................. 5

Typical Performance Characteristics ............................................. 6

Theory of Operation ........................................................................ 8

Applications................................................................................... 8

REVISION HISTORY

1/05—Rev. A to Rev. B

Changes to Specifications................................................................ 3

Change to Pin Configuration.......................................................... 5

Change to Table 5 ............................................................................. 8

Changes to Self Test Section............................................................ 8

Removed R
Change to Design Trade-Offs for Selecting Filter Characteristics:

The Noise/BW Trade-Off Section ...............................................8

Changes to Using the ADXL311 with

Operating Voltages Other than 3 V Section .............................. 9

Updated Outline Dimensions....................................................... 10

Changes to Ordering Guide.......................................................... 10

Selection Section .................................................... 8

BIAS

Design Trade-Offs for Selecting Filter Characteristics:

The Noise/BW Trade-Off.............................................................8

Using the ADXL311 with

Operating Voltages Other than 3 V ............................................9

Using the ADXL311 as a Dual-Axis Tilt Sensor .......................9

Outline Dimensions....................................................................... 10

Ordering Guide .......................................................................... 10

7/03—Rev. 0 to Rev. A

Change to OUTLINE DIMENSIONS..........................................10

Revision 0: Initial Version

Rev. B | Page 2 of 12

ADXL311

SPECIFICATIONS

TA = 25°C, VDD = 3 V, acceleration = 0 g, unless otherwise noted.

Table 1.

Parameter Conditions Min Typ Max Unit

SENSOR INPUT Each axis

Measurement Range ±2
Nonlinearity Best fit straight line 0.2 % of FS
Aligment Error1 ±1 Degrees
Aligment Error X sensor to Y sensor ±0.1 Degrees
Cross-Axis Sensitivity2 ±2 %

SENSITIVITY Each axis

Sensitivity at X

, Y

V

FILT

FILT

= 3 V 174 mV/g

DD

Sensitivity Tolerance (part to part) ±15 %
Sensitivity Change due to Temperature3 ∆ from 25°C ±0.02 %/°C

0 g BIAS LEVEL Each axis

0 g Voltage X

, Y

V

FILT

FILT

= 3 V 1.2 1.5 1.8 V

DD

0 g Offset vs. Temperature ∆ from 25°C ±1.0 mg/°C

NOISE PERFORMANCE

Noise Density @ 25°C 300

FREQUENCY RESPONSE

−3 dB Bandwidth @ Pin X

and Pin Y

FILT

3 kHz

FILT

Sensor Resonant Frequency 5.5 kHz

FILTER

R

Tolerance 32 kΩ nominal ±15 %

FILT

Minimum Capacitance @ Pin X

and Pin Y

FILT

1000 pF

FILT

SELF TEST

X

, Y

Self Test 0 to Self Test 1 50 mV

FILT

FILT

POWER SUPPLY

Operating Voltage Range 2.4 5.25 V
Quiescent Supply Current 0.4 1.0 mA
Turn-On Time4 160 × C

+ 4 ms

FILT

TEMPERATURE RANGE

Operating Range 0 70 °C

1

Alignment error is specified as the angle between the true and indicated axis of sensitivity.

2

Cross axis sensitivity is the algebraic sum of the alignment and the inherent sensitivity errors.

3

Defined as the change from ambient to maximum temperature, or ambient to minimum temperature.

4

C

in µF.

FILT

g

µg/√Hz

rms

Rev. B | Page 3 of 12

ADXL311

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Acceleration
(Any Axis, Unpowered)

Acceleration
(Any Axis, Powered, V

VDD –0.3 V to + 6 V
All Other Pins –0.3 V to VDD + 0.3 V
Output Short-Circuit Duration,

(Any Pin to Common)
Operating Temperature Range –55°C to +125°C
Storage Temperature –65°C to +150°C

= 3 V)

DD

3,500 g, 0.5 ms

3,500 g, 0.5 ms

Indefinite

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

Table 3. Package Characteristics

Package Type

8-Lead LCC 120°C/W 20°C/W <1.0 g

θJC

θ

JA

Device Weight

Rev. B | Page 4 of 12