Analog Devices ADXL150 Datasheet

SELF-TEST

+V

S

2

25kV

5kV

ADXL150

GAIN

AMP

OFFSET

NULL

COM

0.1mF

BUFFER

AMP

DEMODULATORSENSOR

+V

S

TP

(DO NOT CONNECT)

V

OUT

9

CLOCK

SELF-TEST

5kV

25kV

ADXL250

GAIN
AMP

Y OFFSET

NULL

COM

0.1mF

BUFFER

AMP

DEMODULATOR

+V

S

TP

(DO NOT CONNECT)

25kV

5kV

GAIN

AMP

BUFFER

AMP

DEMODULATOR

V

OUT

Y

X OFFSET

NULL

SENSOR

+V

S

2

CLOCK

SENSOR

V

OUT

X

65 g to 650 g, Low Noise, Low Power,

a

Single/Dual Axis i

FEATURES
Complete Acceleration Measurement System

on a Single Monolithic IC
80 dB Dynamic Range
Pin Programmable 650
Low Noise: 1 m

g

g

or 625g Full Scale

/√Hz Typical

Low Power: <2 mA per Axis
Supply Voltages as Low as 4 V
2-Pole Filter On-Chip
Ratiometric Operation
Complete Mechanical & Electrical Self-Test
Dual & Single Axis Versions Available
Surface Mount Package

GENERAL DESCRIPTION

The ADXL150 and ADXL250 are third generation ± 50 g sur-

face micromachined accelerometers. These improved replace­ments for the ADXL50 offer lower noise, wider dynamic range,
reduced power consumption and improved zero g bias drift.

The ADXL150 is a single axis product; the ADXL250 is a fully
integrated dual axis accelerometer with signal conditioning on a
single monolithic IC, the first of its kind available on the com­mercial market. The two sensitive axes of the ADXL250 are

orthogonal (90°) to each other. Both devices have their sensitive

axes in the same plane as the silicon chip.

The ADXL150/ADXL250 offer lower noise and improved
signal-to-noise ratio over the ADXL50. Typical S/N is 80 dB,
allowing resolution of signals as low as 10 mg, yet still providing

a ±50 g full-scale range. Device scale factor can be increased

from 38 mV/g to 76 mV/g by connecting a jumper between

and the offset null pin. Zero g drift has been reduced to

V

OUT

0.4 g over the industrial temperature range, a 10× improvement

over the ADXL50. Power consumption is a modest 1.8 mA
per axis. The scale factor and zero g output level are both

MEM



S

Accelerometers

ADXL150/ADXL250

FUNCTIONAL BLOCK DIAGRAMS

ratiometric to the power supply, eliminating the need for a volt­age reference when driving ratiometric A/D converters such as
those found in most microprocessors. A power supply bypass
capacitor is the only external component needed for normal
operation.

The ADXL150/ADXL250 are available in a hermetic 14-lead

surface mount cerpac package specified over the 0°C to +70°C
commercial and –40°C to +85°C industrial temperature ranges.

Contact factory for availability of devices specified over automo­tive and military temperature ranges.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 1998

i

MEM

S

is a registered trademark of Analog Devices, Inc.

REV. 0

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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

(TA = +258C for J Grade, TA = –408C to +858C for A Grade,

ADXL150/ADXL250–SPECIFICATIONS

Parameter Conditions Min Typ Max Min Typ Max Units

SENSOR

Guaranteed Full-Scale Range ±40 ±50 ±40 ±50 g

Nonlinearity 0.2 0.2 % of FS
Package Alignment Error

Sensor-to-Sensor Alignment Error ±0.1 Degrees

Transverse Sensitivity

SENSITIVITY

Sensitivity (Ratiometric)

Sensitivity Drift Due to Temperature Delta from 25°C to T

ZERO g BIAS LEVEL

Output Bias Voltage

Zero g Drift Due to Temperature Delta from 25°C to T

ZERO-g OFFSET ADJUSTMENT

Voltage Gain Delta V

Input Impedance 20 30 20 30 kΩ

NOISE PERFORMANCE

Noise Density

5

Clock Noise 5 5 mV p-p

FREQUENCY RESPONSE

–3 dB Bandwidth 900 1000 900 1000 Hz
Bandwidth Temperature Drift T
Sensor Resonant Frequency Q = 5 24 24 kHz

SELF-TEST

Output Change

6

Logic “1” Voltage V
Logic “0” Voltage 1.0 1.0 V

Input Resistance To Common 30 50 30 50 kΩ

OUTPUT AMPLIFIER

Output Voltage Swing I
Capacitive Load Drive 1000 1000 pF

POWER SUPPLY (V

Functional Voltage Range 4.0 6.0 4.0 6.0 V
Quiescent Supply Current ADXL150 1.8 3.0 mA

TEMPERATURE RANGE

Operating Range J 0 +70 0 +70 °C
Specified Performance A –40 +85 –40 +85 °C

NOTES

1

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

2

Transverse sensitivity is measured with an applied acceleration that is 90 degrees from the indicated axis of sensitivity.

3

Ratiometric: V
doubled by connecting V

4

Ratiometric, proportional to VS/2. See Figure 21.

5

See Figure 11 and Device Bandwidth vs. Resolution section.

6

Self-test output varies with supply voltage.

7

When using ADXL250, both Pins 13 and 14 must be connected to the supply for the device to function.

Specifications subject to change without notice.

OUT

= V

1

2

3

Y Channel 33.0 38.0 43.0 mV/g
X Channel 33.0 38.0 43.0 33.0 38.0 43.0 mV/g

or T

MIN

MAX

4

or T

MIN

MAX

/Delta V

MIN

OUT

to T

MAX

OS PIN

ST Pin from Logic “0” to “1” 0.25 0.40 0.60 0.25 0.40 0.60 V

= ±100 µA 0.25 V

OUT

7

)

S

ADXL250 (Total 2 Channels) 3.5 5.0 mA

/2 + (Sensitivity × VS/5 V × a) where a = applied acceleration in gs, and V

S

to the offset null pin.

OUT

VS = +5.00 V, Acceleration = Zero g, unless otherwise noted)

ADXL150JQC/AQC ADXL250JQC/AQC

±1 ±1 Degrees

±2 ±2%

±0.5 ±0.5 %

VS/2 – 0.35 VS/2 VS/2 + 0.35 VS/2 – 0.35 VS/2 VS/2 + 0.35 V

0.2 0.3 g

0.45 0.50 0.55 0.45 0.50 0.55 V/V

1 2.5 1 2.5 mg/√Hz

50 50 Hz

– 1 VS – 1 V

S

– 0.25 0.25 VS – 0.25 V

S

= supply voltage. See Figure 21. Output scale factor can be

S

–2–

REV. 0

ADXL150/ADXL250

TOP VIEW

(Not to Scale)

ADXL150

14

1

78

NC
NC

NC
NC

NC

COMMON

V

S

NC
NC

V

OUT

SELF-TEST
ZERO

g

ADJ

TP (DO NOT CONNECT)

NC = NO CONNECT

ZERO

g

ADJ Y

V

OUT

Y

NC

NC

COMMON

V

S

V

S

NC
NC

ZERO

g

ADJ X

SELF-TEST

V

OUT

X

TOP VIEW

(Not to Scale)

ADXL250

14

1

78

NC

TP (DO NOT CONNECT)

NOTE: WHEN USING ADXL250, BOTH PINS 13 AND 14 NEED
TO BE CONNECTED TO SUPPLY FOR DEVICE TO FUNCTION

NC

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS*

Acceleration (Any Axis, Unpowered for 0.5 ms) . . . . . . 2000 g

Acceleration (Any Axis, Powered for 0.5 ms) . . . . . . . . . 500 g

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to +7.0 V

+V

S

Output Short Circuit Duration

, V

(V

OUT

Terminals to Common) . . . . . . . . . . . Indefinite

REF

Operating Temperature . . . . . . . . . . . . . . . . . –55°C to +125°C

Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C

*Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent damage to the device. This is a stress rating only; the functional operation of
the device at these or any other conditions above those indicated in the operational
sections of this specification is not implied. Exposure to absolute maximum rating
conditions for extended periods may affect device reliability.

Drops onto hard surfaces can cause shocks of greater than 2000 g
and exceed the absolute maximum rating of the device. Care
should be exercised in handling to avoid damage.

1

ADXL150

TOP VIEW

(Not to Scale)

78

14

A

X

1

ADXL250

TOP VIEW

(Not to Scale)

A

78

14

A

X

908

Y

Package Characteristics

Package u

JA

u

JC

Device Weight

14-Lead Cerpac 110°C/W 30°C/W 5 Grams

ORDERING GUIDE

Model Temperature Range

ADXL150JQC 0°C to +70°C
ADXL150AQC –40°C to +85°C
ADXL250JQC 0°C to +70°C
ADXL250AQC –40°C to +85°C

PIN CONNECTIONS

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 the ADXL150/ADXL250 feature 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.

POSITIVE A = POSITIVE V

POSITIVE A = POSITIVE V

OUT

OUT

Figure 1. ADXL150 and ADXL250 Sensitive Axis
Orientation

REV. 0

–3–

ADXL150/ADXL250

14

1

78

A

X

ADXL150

14

1

78

A

X

ADXL250

A

Y

GLOSSARY OF TERMS

Acceleration: Change in velocity per unit time.

Acceleration Vector: Vector describing the net acceleration

acting upon the ADXL150/ADXL250.

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

2

or 9.807 meters/s2.

Nonlinearity: The maximum deviation of the ADXL150/
ADXL250 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 (at 50 g).

Resonant Frequency: The natural frequency of vibration of
the ADXL150/ADXL250 sensor’s central plate (or “beam”). At
its resonant frequency of 24 kHz, the ADXL150/ADXL250’s
moving center plate has a slight peak in its frequency response.

Sensitivity: The output voltage change per g unit of accelera-
tion applied, specified at the V

pin in mV/g.

OUT

Total Alignment Error: Net misalignment of the ADXL150/
ADXL250’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
acceleration that appears at V

OUT

.

Transverse Axis: The axis perpendicular (90°) to the axis of

sensitivity.

Zero g Bias Level: The output voltage of the ADXL150/
ADXL250 when there is no acceleration (or gravity) acting
upon the axis of sensitivity. The output offset is the difference
between the actual zero g bias level and (V

S

/2).

Polarity of the Acceleration Output

The polarity of the ADXL150/ADXL250 output is shown in
Figure 1. When its sensitive axis is oriented to the earth’s gravity
(and held in place), it will experience an acceleration of +1 g.
This corresponds to a change of approximately +38 mV at the
output pin. Note that the polarity will be reversed if the package

is rotated 180°. The figure shows the ADXL250 oriented so that
its “X” axis measures +1 g. If the package is rotated 90° clock-

wise (Pin 14 up, Pin 1 down), the ADXL250’s “Y” axis will now
measure +1 g.

Figure 2. Output Polarity

Acceleration Vectors

The ADXL150/ADXL250 is a sensor designed to measure
accelerations that result from an applied force. It responds to
the component of acceleration on its sensitive X axis (ADXL150)
or on both the “X” and “Y” axis (ADXL250).

–4–

REV. 0

ADXL150/ADXL250

TIME – 0.2ms/Div

OUTPUT RESPONSE

500g INPUT

600

g

500

g

400

g

300

g

200

g

100

g

0

g

60

g

50

g

40

g

30

g

20

g

10

g

0

g

Typical Characteristics

5.0

4.0

3.0

2.0

1.0
0

–1.0
–2.0

ERROR FROM IDEAL – %

–3.0
–4.0

–5.0

4.0 4.5 5.0 5.5 6.0

POWER SUPPLY VOLTAGE

(@+5 V dc, +258C with a 38 mV/g Scale Factor unless otherwise noted)

Figure 3. Typical Sensitivity Error from Ideal Ratiometric
Response for a Number of Units

2.5

2.0

1.5

1.0

0.5
0

ERROR – %

–0.5
–1.0

–1.5
–2.0

4.0 4.5 5.0 5.5 6.0
SUPPLY VOLTAGE

Figure 4. Offset Error of Zero g Level from Ideal
V

/2 Response as a Percent of Full-Scale for a Number

S

of Units

6

0

–6

–12
–18

–24
–30
–36
–42

TYPICAL OUTPUT RESPONSE IN dB

–48

100 1k

RESONANCE

FREQUENCY – Hz

BEAM

PACKAGE
RESONANCE

10k

Figure 6. Typical Output Response vs. Frequency of
ADXL150/ADXL250 on a PC Board that Has Been
Conformally Coated

30

20

10

0

DRIFT – mV

g

–10

ZERO

–20

–30

–40 –30 –20 –10 10 20 30 60

05040 80 90 100

TEMPERATURE – 8C

70

Figure 7. Typical Zero g Drift for a Number of Units

2.4

2.2

2

1.8

1.6

SUPPLY CURRENT – mA

1.4

1.2

464.5
SUPPLY VOLTAGE – Volts

Figure 5. Typical Supply Current vs. Supply Voltage

REV. 0

+1058C

+258C

–408C

5 5.5

Figure 8. Typical 500 g Step Recovery at the Output

–5–