Analog Devices ADXL311 a Datasheet

Low Cost, Ultracompact

±2

g

Dual-Axis Accelerometer

FEATURES

Low cost
High resolution
Dual-axis accelerometer on a single IC chip
5 mm × 5 mm × 2 mm CLCC 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 in cost-sensitive applications
Smart handheld devices
Computer security
Input devices
Pedometers and activity monitors
Game controllers
Toys and entertainment products

ADXL311

GENERAL DESCRIPTION

The ADXL311 is a low cost, 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 100 million Analog
Devices accelerometers shipped to date, with demonstrated
1 FIT reliability (1 failure per 1 billion device operating hours).

The ADXL311 will measure acceleration with a full-scale

g.

range of ±2
acceleration (e.g., vibration) and static acceleration (e.g.,
gravity). The outputs are analog voltages proportional to
acceleration.

The typical noise floor is 300 µ
2 m

g

(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
of 1 Hz to 2 kHz may be selected to suit the application.

The ADXL311 is available in a 5 mm × 5 mm × 2 mm
8-terminal hermetic CLCC package

The ADXL311 can measure both dynamic

g

/√Hz allowing signals below

and CY at the X

X

FILT

and Y

pins. Bandwidths

FILT

3.0V

V

DD

DEMOD

ADXL311JE

DEMOD

R
32kΩ

32kΩ
R

X SENSOR

CDC

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable.
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
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective companies.

OSCILLATOR

Y SENSOR

COM Y

Figure 1. Functional Block Diagram

FILT

FILT

C

OUT

X

X

OUT

C

Y

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Tel: [phone] www.analog.com
Fax: [phone] © 2003 Analog Devices, Inc. All rights reserved.

SELF TEST

BIAS

200kΩ

ADXL311

TABLE OF CONTENTS

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

Pin Configuration and Functional Descriptions...........................9

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

Typical Performance Characteristics............................................. 5

Theory of Operation........................................................................ 7

Applications................................................................................... 7

Design Trade-Offs for Selecting Filter Characteristics: The

Noise/BW Trade-Off.................................................................... 7

Using the ADXL311 as a Dual-Axis Tilt Sensor....................... 8

REVISION HISTORY

7/03—Data sheet changed from Rev. 0 to Rev. A.

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

Revision 0: Initial Version

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

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

Rev. A | Page 2 of 12

ADXL311

SPECIFICATIONS

Table 1. TA = 25oC, VDD = 3 V, R

Parameter Conditions Min Typ Max Units

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 0.01 Degrees
Cross Axis Sensitivity2 ±2 %

SENSITIVITY Each Axis

Sensitivity at X
Sensitivity Change due to Temperature3 Delta from 25°C −0.025 %/°C

ZERO g BIAS LEVEL Each Axis

0 g Voltage X
0 g Offset vs. Temperature Delta from 25°C 2.0 mg/°C

NOISE PERFORMANCE

Noise Density @25°C 300

FREQUENCY RESPONSE

3 dB Bandwidth At Pins X
Sensor Resonant Frequency 10 kHz

FILTER

R

Tolerance 32 kΩ Nominal ±15 %

FILT

Minimum Capacitance At Pins X

SELF TEST

X

, Y

Self Test 0 to 1 45 mV

FILT

FILT

POWER SUPPLY

Operating Voltage Range 2.7 5.25 V
Quiescent Supply Current 0.4 1.0 mA
Turn-On Time 160 × C

TEMPERATURE RANGE

Operating Range 0 70 °C

, Y

V

FILT

FILT

, Y

V

FILT

FILT

= 125 kΩ, Acceleration = 0 g, unless otherwise noted.)

BIAS

= 3 V 140 167 195 mV/g

DD

= 3 V 1.2 1.5 1.8 V

DD

, Y

6 kHz

FILT

FILT

, Y

1000 pF

FILT

FILT

+ 0.3 ms

FILT

g

µg/√Hz

RMS

1

Alignment error is specified as the angle between the true and indicated axis of sensitivity ( ). Figure 1

2

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

3

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

Rev. A | 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 +0.6 V
Output Short-Circuit Duration,

(Any Pin to Commom)
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

Table 3. Package Characteristics

Package Type

8-Lead CLCC 120°C/W TBD°C/W <1.0 gram

θJC

θ

JA

Device Weight

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress rat­ing only and 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.

Rev. A | Page 4 of 12