ANALOG DEVICES ADXL001 Service Manual

High Performance,

V

FEATURES

High performance accelerometer

±70 g, ±250 g, and ±500 g wideband ranges available 22 kHz resonant frequency structure High linearity: 0.2% of full scale

Low noise: 4 mg/√Hz Sensitive axis in the plane of the chip Frequency response down to dc Full differential signal processing High resistance to EMI/RFI Complete electromechanical self-test Output ratiometric to supply Velocity preservation during acceleration input overload Low power consumption: 2.5 mA typical 8-terminal, hermetic ceramic, LCC package

APPLICATIONS

Vibration monitoring Shock detection Sports diagnostic equipment Medical instrumentation Industrial monitoring

GENERAL DESCRIPTION

The ADXL001 is a major advance over previous generations of accelerometers providing high performance and wide bandwidth. This part is ideal for industrial, medical, and military applications where wide bandwidth, small size, low power, and robust performance are essential.

FUNCTIONAL BLOCK DIAGRAM

S

V

DD

TIMING

V

DD2

GENERATOR

Wide Bandwidth Accelerometer

ADXL001

Using the Analog Devices, Inc. proprietary fifth-generation iMEMs® process enables the ADXL001 to provide the desired dynamic range that extends from ±70 g to ±500 g in combination with 22 kHz of bandwidth. The accelerometer output channel passes through a wide bandwidth differential-to-singleended converter, which allows access to the full mechanical performance of the sensor.

The part can operate on voltage supplies from 3.3 V to 5 V.

The ADXL001 also has a self-test (ST) pin that can be asserted to verify the full electromechanical signal chain for the accelerometer channel.

The ADXL001 is available in the industry-standard 8-terminal LCC and is rated to work over the extended industrial temperature range (−40°C to +125°C).

15

12

9

6

3

0

–3

RESPONSE (d B)

–6

–9

–12

–15

1 10 100 1k 10k 100k

Figure 1. Sensor Frequency Response

ADXL001

FREQUENCY (Hz)

07510-102

DIFFERENTIAL

MOD

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 owners.

SENSOR

SELF-TEST

ST

DEMOD

AMP

COM

Figure 2.

OUTPUT

AMPLIFIER

X

OUT

07510-001

ADXL001

REVISION HISTORY

2/10—Rev. 0 to Rev. A

Added -250 and -500 models ............................................ Universal

Changes to Table 1 ............................................................................ 3

Changes to Table 2 ............................................................................ 4

Added Figure 9 through Figure 18 ................................................. 8

Changes to Ordering Guide .......................................................... 14

1/09—Revision 0: Initial Version

Rev. A | Page 2 of 16

ADXL001

SPECIFICATIONS

SPECIFICATIONS FOR 3.3 V OPERATION

TA = −40°C to +125°C, VS = 3.3 V ± 5% dc, acceleration = 0 g, unless otherwise noted.

Table 1.

ADXL001-70 ADXL001-250 ADXL001-500 Parameter Conditions Min Typ Max Min Typ Max Min Typ Max Unit

SENSOR

Nonlinearity 0.2 2 0.2 2 0.2 2 %

Cross-Axis Sensitivity

Resonant Frequency 22 22 22 kHz

Quality Factor 2.5 2.5 2.5

SENSITIVITY

Full-Scale Range I

Sensitivity 100 Hz 16.0 4.4 2.2 mV/g

OFFSET Ratiometric

Zero-g Output 1.35 1.65 1.95 1.35 1.65 1.95 1.35 1.65 1.95 V

NOISE

Noise 10 Hz to 400 Hz 85 95 105 mg rms

Noise Density 10 Hz to 400 Hz 3.3 3.65 4.25 mg/√Hz

FREQUENCY RESPONSE

−3 dB Frequency 32 32 32 kHz

−3 dB Frequency Drift Over Temperature

SELF-TEST

Output Voltage Change 400 125 62 mV Logic Input High 2.1 2.1 2.1 V Logic Input Low 0.66 0.66 0.66 V Input Resistance To ground 30 50 30 50 30 50 kΩ

OUTPUT AMPLIFIER

Output Swing I

Capacitive Load 1000 1000 1000 pF PSRR (CFSR) DC to 1 MHz 0.9 0.9 0.9 V/V POWER SUPPLY (VS)

Functional Range 3.135 6 3.135 6 3.135 6 V

I

2.5 5 2.5 5 2.5 5 mA

SUPPLY

Turn-On Time 10 10 10 ms

Includes package alignment

≤ ±100 μA −70 +70 −250 +250 −500 +500

OUT

2 2 2 %

= ±100 μA 0.2 VS − 0.2 0.2 VS − 0.2 0.2 VS − 0.2 V

OUT

2 2 2 %

g

Rev. A | Page 3 of 16

ADXL001

SPECIFICATIONS FOR 5 V OPERATION

TA = -40°C to +125°C, VS = 5 V ± 5% dc, acceleration = 0 g, unless otherwise noted.

Table 2.

ADXL001-70 ADXL001-250 ADXL001-500 Parameter Conditions Min Typ Max Min Typ Max Min Typ Max Unit

SENSOR

Nonlinearity 0.2 2 0.2 2 0.2 2 % Cross-Axis Sensitivity

Includes package

alignment Resonant Frequency 22 22 22 kHz Quality Factor 2.5 2.5 2.5

SENSITIVITY

Full-Scale Range I

≤ ±100 μA −70 +70 −250 +250 −500 +500

OUT

Sensitivity 100 Hz 24.2 6.7 3.3 mV/g

OFFSET Ratiometric

Zero-g Output 2.00 2.5 3.00 2.00 2.5 3.00 2.00 2.5 3.00 V

NOISE

Noise 10 Hz to 400 Hz 55 60 70 mg rms Noise Density 10 Hz to 400 Hz 2.15 2.35 2.76 mg/√Hz

FREQUENCY RESPONSE

−3 dB Frequency 32 32 32 kHz

−3 dB Frequency Drift

2 2 2 %

Over Temperature

SELF-TEST

Output Voltage Change 1435 445 217 mV Logic Input High 3.3 3.3 3.3 V Logic Input Low 0.66 0.66 0.66 V Input Resistance To ground 30 50 30 50 30 50 kΩ

OUTPUT AMPLIFIER

Output Swing I

= ±100 μA 0.2 VS − 0.2 0.2 VS − 0.2 0.2 VS − 0.2 V

OUT

Capacitive Load 1000 1000 1000 pF

PSRR (CFSR) DC to 1 MHz 0.9 0.9 0.9 V/V POWER SUPPLY (VS)

Functional Range 3.135 6 3.135 6 3.135 6 V I

4.5 9 4.5 9 4.5 9 mA

SUPPLY

Turn-On Time 10 10 10 ms

2 2 2 %

g

Rev. A | Page 4 of 16

ADXL001

RECOMMENDED SOLDERING PROFILE

Table 3. Soldering Profile Parameters

Profile Feature Sn63/Pb37 Pb-Free

Average Ramp Rate (TL to TP) 3°C/sec maximum 3°C/sec maximum Preheat

Minimum Temperature (T

Maximum Temperature (T Time (T T

SMAX

to T

SMIN

), ts 60 sec to 120 sec 60 sec to 150 sec

SMAX

to TL

Ramp-Up Rate 3°C/sec 3°C/sec Time Maintained Above Liquidous (tL)

Liquidous Temperature (TL) 183°C 217°C

Liquidous Time (tL) 60 sec to 150 sec 60 sec to 150 sec Peak Temperature (TP) 240°C + 0°C/−5°C 260°C + 0°C/−5°C Time Within 5°C of Actual Peak Temperature (tP) 10 sec to 30 sec 20 sec to 40 sec Ramp-Down Rate 6°C/sec maximum 6°C/sec maximum Time 25°C to Peak Temperature (t

Soldering Profile Diagram

) 100°C 150°C

SMIN

) 150°C 200°C

SMAX

) 6 minute maximum 8 minute maximum

PEAK

CRITICAL ZONE

TO T

t

T

P

T

L

T

SMAX

RAMP-UP

P

T

L

P

t

L

T

SMIN

t

TEMPERATURE (T)

S

PREHEAT

t

PEAK

TIME (t)

RAMP-DOWN

07510-022

Figure 3. Soldering Profile Diagram

Rev. A | Page 5 of 16

ADXL001

ABSOLUTE MAXIMUM RATINGS

Table 4.

Parameter Rating

Acceleration (Any Axis, Unpowered and

Powered) Supply Voltage, VS −0.3 V to +7.0 V Output Short-Circuit Duration (V Storage Temperature Range −65°C to +150°C Operating Temperature Range −55°C to +125°C Soldering Temperature (Soldering, 10 sec) 245°C

to GND) Indefinite

OUT

4000 g

Drops onto hard surfaces can cause shocks of greater than 4000 g and can exceed the absolute maximum rating of the device. Exercise care during handling to avoid damage.

ESD CAUTION

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.

Rev. A | Page 6 of 16

ADXL001

V

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

DD2

8

DNC = DO NOT CONNE CT

Table 5. Pin Function Descriptions

Pin No. Mnemonic Description

1, 2, 5 DNC Do Not Connect. 3 COM Common. 4 ST Self-Test Control (Logic Input). 6 X 7 VDD 3.135 V to 6 V. Connect to V 8 V

X-Axis Acceleration Output.

OUT

3.135 V to 6 V. Connect to VDD.

DD2

1

DNC

2

DNC

3

COM

ADXL001

(Not to Scale)

Figure 4. Pin Configuration

.

4

ST

TOP VIEW

7

V

DD

6

X

OUT

5

DNC

07510-004

Rev. A | Page 7 of 16

ADXL001

TYPICAL PERFORMANCE CHARACTERISTICS

VS = 3.3 V, TA = 25°C, unless otherwise noted.

60

25

50

40

30

20

PERCENT OF POPULATI ON

10

0

–0.07

–0.06

–0.05

–0.04

–0.03

–0.02

–0.01

VOLTS

0

0.01

0.02

0.03

Figure 5. Zero-g Bias Deviation from Ideal

45

40

35

30

25

20

15

PERCENT OF POPULATI ON

10

5

0

–0.07

–0.06

–0.05

–0.04

–0.03

–0.02

–0.01

VOLTS

0

0.01

0.02

0.03

Figure 6. Zero-g Bias Deviation from Ideal (TA = 125°C)

25

20

15

10

PERCENT OF POPULATION

5

07510-005

0.04

0.05

0.06

0.07

0

15.2

15.3

15.4

15.5

15.6

15.7

15.8

16.0

15.9

16.1

16.2

16.3

16.4

(mV/g)

16.5

07510-008

16.6

16.8

16.7

Figure 8. ADXL001-70, Sensitivity Distribution (TA = 125°C)

35

30

25

20

15

10

PERCENT OF PO P UL ATION

5

07510-006

0.04

0.05

0.06

0.07

0

4.32

4.34

4.36

4.38

4.42

4.44

4.46

4.30

4.40

(mV/g)

4.48

4.50

07510-024

4.52

4.54

Figure 9: ADXL001-250, Sensitivity Distribution

30

20

15

10

PERCENT OF PO P UL ATION

5

0

15.2

15.3

15.4

15.5

15.6

15.7

15.8

15.9

(mV/g)

Figure 7. ADXL001-70, Sensitivity Distribution

25

20

15

10

PERCENT OF POPULATION

5

07510-007

16.0

16.1

16.2

16.3

16.4

16.6

16.5

16.8

16.7

0

4.32

4.34

4.36

4.38

4.42

4.44

4.46

4.48

4.30

4.40

(mV/g)

4.52

4.50

07510-025

4.56

4.54

Figure 10: ADXL001-250, Sensitivity Distribution (TA = 125°C)

Rev. A | Page 8 of 16

ADXL001

30

25

20

15

10

PERCENT OF POPULATION

5

0

2.17

2.18

2.19

2.21

2.22

2.23

2.24

2.25

2.20

(mV/g)

2.26

Figure 11. ADXL001-500, Sensitivity Distribution

30

25

20

15

10

PERCENT OF POPULATION

5

0

2.17

2.18

2.19

2.21

2.22

2.23

2.24

2.25

2.26

2.28

2.20

(mV/g)

2.27

Figure 12. ADXL001-500, Sensitivity Distribution (TA = 125°C)

25

20

15

10

PERCENT OF POPULATION

5

07510-026

2.27

0

110

112

114

116

118

120

122

126

124

128

130

132

134

138

(mV)

136

07510-028

142

140

Figure 14. ADXL001-250, Self-Test Delta

40

35

30

25

20

15

10

PERCENT OF POPULATION

5

07510-027

2.29

0

55 56 57 58 59 60 61 62 63 64 65 66 67

(mV)

07510-029

Figure 15. ADXL001-500, Self-Test Delta

30

20

15

10

PERCENT OF PO P UL ATION

5

435

07510-009

440

0

360

365

370

375

380

385

390

400

395

405

410

415

420

430

425

(mV)

Figure 13. ADXL001-70, Self-Test Delta

25

20

15

10

PERCENT OF PO P UL ATION

5

0

2.000

2.075

2.150

2.225

2.300

2.375

2.450

2.600

2.525

2.675

2.750

Figure 16. I

(mA)

Distribution

SUPPLY

07510-010

2.825

2.900

Rev. A | Page 9 of 16

ADXL001

40

35

30

25

20

15

10

PERCENT OF POPULATION

5

07510-012

2.925

3.000

07510-011

CH1 500mV

B

CH2 500mV

W

B

M10.0µs A CH2 1. 38V

W

T 42.80%

Figure 18. Turn-On Characteristic (10 μs per DIV)

0

2.100

2.175

2.250

2.325

2.400

2.475

2.550

2.700

2.625

2.775

(mA)

Figure 17. I

SUPPLY

at 125°C

2.850

Rev. A | Page 10 of 16

ADXL001

THEORY OF OPERATION

DESIGN PRINCIPLES

The ADXL001 accelerometer provides a fully differential sensor structure and circuit path for excellent resistance to EMI/RFI interference.

This latest generation SOI MEMS device takes advantage of mechanically coupled but electrically isolated differential sensing cells. This improves sensor performance and size because a single proof mass generates the fully differential signal. The sensor signal conditioning also uses electrical feedback with zero-force feedback for improved accuracy and stability. This force feedback cancels out the electrostatic forces contributed by the sensor circuitry.

Figure 19 is a simplified view of one of the differential sensor cell blocks. Each sensor block includes several differential capacitor unit cells. Each cell is composed of fixed plates attached to the device layer and movable plates attached to the sensor frame. Displacement of the sensor frame changes the differential capacitance. On-chip circuitry measures the capacitive change.

MECHANICAL SENSOR

The ADXL001 is built using the Analog Devices SOI MEMS sensor process. The sensor device is micromachined in-plane in the SOI device layer. Trench isolation is used to electrically isolate, but mechanically couple, the differential sensing elements. Single-crystal silicon springs suspend the structure over the handle wafer and provide resistance against acceleration forces.

ANCHOR

MOVABLE

PLATE

CAPACITORS

UNIT

SENSING

CELL

ACCELERATION

Figure 19. Simplified View of Sensor Under Acceleration

MOVING

PLATE

FIXED PLATES

ANCHOR

FRAME

UNIT FORCING CELL

07510-019

Rev. A | Page 11 of 16

ADXL001

V

APPLICATIONS INFORMATION

APPLICATION CIRCUIT

Figure 20 shows the standard application circuit for the ADXL001. Note that V

and V

DD

should always be connected together.

DD2

The output is shown connected to a 1000 pF output capacitor for improved EMI performance and can be connected directly to an ADC input. Use standard best practices for interfacing with an ADC and do not omit an appropriate antialiasing filter.

S

C

VDD

0.1µF

DNC

COM

ST

DNC = DO NOT CONNE CT

1

2

3

Figure 20. Application Circuit

V

DD2

8

ADXL001

TOP VIEW

(Not to Scale)

4

ST

V

DD

7

X

OUT

6

C

OUT

5

1nF

DNC

X

OUT

07510-023

SELF-TEST

The fixed fingers in the forcing cells are normally kept at the same potential as that of the movable frame. When the digital self-test input is activated, the ADXL001 changes the voltage on the fixed fingers in these forcing cells on one side of the moving plate. This potential creates an attractive electrostatic force, causing the sensor to move toward those fixed fingers. The entire signal channel is active; therefore, the sensor displacement causes a change in X operation of the sensor, interface electronics, and accelerometer channel electronics.

Do not expose the ST pin to voltages greater than V this cannot be guaranteed due to the system design (for instance, if there are multiple supply voltages), then a low V diode between ST and V

. The ADXL001 self-test function verifies proper

OUT

+ 0.3 V. If

S

clamping

F

is recommended.

S

ACCELERATION SENSITIVE AXIS

The ADXL001 is an x-axis acceleration and vibration-sensing device. It produces a positive-going output voltage for vibration toward its Pin 8 marking.

PIN 8

07510-002

Figure 21. X

Increases with Acceleration in the Positive X-Axis Direction

OUT

OPERATING VOLTAGES OTHER THAN 5 V

The ADXL001 is specified at VS = 3.3 V and VS = 5 V. Note that some performance parameters change as the voltage is varied.

In particular, the X sensitivity with supply. The output sensitivity (or scale factor) scales proportionally to the supply voltage. At V sensitivity is typically 16 mV/g. At V is nominally 24.2 mV/g. X V

/2 at all supply voltages.

S

3.5

3.0

2.5

2.0

ZERO-g BIAS (V)

1.5

1.0

3.2 3.7 4.2 4.7 5.2 5.7

Figure 22. Typical Zero-g Bias Levels Across Varying Supply Voltages

Self-test response in gravity is roughly proportional to the cube of the supply voltage. For example, the self-test response for the ADXL001-70 at V the self-test response for the ADXL001-70 is approximately 400 mV. To calculate the self-test value at any operating voltage other than 3.3 V or 5 V, the following formula can be applied:

(STΔ @ V

where:

V

is the desired supply voltage.

X

is 3.3 V or 5 V.

V

S

output exhibits ratiometric offset and

OUT

= 3.3 V, the output

S

= 5 V, the output sensitivity

S

zero-g bias is nominally equal to

OUT

NOMINAL ZERO-g

HIGH LIM IT

LOW LIMIT

SUPPLY VOLT AG E ( V)

= 5 V is approximately 1.4 V. At VS = 3.3 V,

S

) = (STΔ @ VS) × (VX/VS)3

X

07510-016

Rev. A | Page 12 of 16

ADXL001

LAYOUT, GROUNDING, AND BYPASSING CONSIDERATIONS

CLOCK FREQUENCY SUPPLY RESPONSE

In any clocked system, power supply noise near the clock frequency may have consequences at other frequencies. An internal clock typically controls the sensor excitation and the signal demodulator for micromachined accelerometers.

If the power supply contains high frequency spikes, they may be demodulated and interpreted as acceleration signals. A signal appears at the difference between the noise frequency and the demodulator frequency. If the power supply noise is 100 Hz away from the demodulator clock, there is an output term at 100 Hz. If the power supply clock is at exactly the same frequency as the accelerometer clock, the term appears as an offset. If the difference frequency is outside the signal bandwidth, the output filter attenuates it. However, both the power supply clock and the accelerometer clock may vary with time or temperature, which can cause the interference signal to appear in the output filter bandwidth.

The ADXL001 addresses this issue in two ways. First, the high clock frequency, 125 kHz for the output stage, eases the task of choosing a power supply clock frequency such that the difference between it and the accelerometer clock remains well outside the filter bandwidth. Second, the ADXL001 has a fully differential signal path, including a pair of electrically isolated, mechanically coupled sensors. The differential sensors eliminate most of the power supply noise before it reaches the demodulator. Good high frequency supply bypassing, such as a ceramic capacitor close to the supply pins, also minimizes the amount of interference.

The clock frequency supply response (CFSR) is the ratio of the response at the output to the noise on the power supply near the accelerometer clock frequency or its harmonics. A CFSR of 0.9 V/V means that the signal at the output is half the amplitude of the supply noise. This is analogous to the power supply rejection ratio (PSRR), except that the stimulus and the response are at different frequencies.

POWER SUPPLY DECOUPLING

For most applications, a single 0.1 μF capacitor, CDC, adequately decouples the accelerometer from noise on the power supply. However, in some cases, particularly where noise is present at the 1 MHz internal clock frequency (or any harmonic thereof), noise on the supply can cause interference on the ADXL001 output. If additional decoupling is needed, a 50 Ω (or smaller) resistor or ferrite bead can be inserted in the supply line. Additionally, a larger bulk bypass capacitor (in the 1 μF to

4.7 μF range) can be added in parallel to C

DC

.

ELECTROMAGNETIC INTERFERENCE

The ADXL001 can be used in areas and applications with high amounts of EMI or with components susceptible to EMI emissions. The fully differential circuitry of the ADXL001 is designed to be robust to such interference. For improved EMI performance, especially in automotive applications, a 1000 pF output capacitor is recommended on the X

output.

OUT

Rev. A | Page 13 of 16

ADXL001

OUTLINE DIMENSIONS

0.031

0.025

0.019

7

5 BOTTOM VIEW

DETAIL A

0.183

0.177 SQ

0.171

R 0.008

(4 PLCS)

0.208

0.197 SQ

0.188

TOP VIEW

0.22

0.15

0.08

(R 4 PLCS)

0.010

0.006

0.002

0.094

0.078

0.062

0.082

0.070

0.058

0.075 REF R 0.008

(8 PLCS)

0.055

0.050

0.045

(OPTION 2)

Figure 23. 8-Terminal Ceramic Leadless Chip Carrier [LCC]

(E-8-1)

Dimensions shown in inches

ORDERING GUIDE

Model1 Temperature Range g Range Package Description Package Option

ADXL001-70BEZ −40°C to +125°C ±70 g 8-Terminal LCC E-8-1 ADXL001-70BEZ-R7 −40°C to +125°C ±70 g 8-Terminal LCC E-8-1 ADXL001-250BEZ ADXL001-250BEZ-R7 −40°C to +125°C ±250 g 8-Terminal LCC E-8-1 ADXL001-500BEZ −40°C to +125°C ±500 g 8-Terminal LCC E-8-1 ADXL001-500BEZ-R7 −40°C to +125°C ±500 g 8-Terminal LCC E-8-1 EVAL-ADXL001-250Z Evaluation Board EVAL-ADXL001-500Z Evaluation Board EVAL-ADXL001-70Z Evaluation Board

1

Z = RoHS Compliant Part.

−40°C to +125°C ±250 g 8-Terminal LCC E-8-1

1

3

0.019 SQ

(PLATING OPTION 1, SEE DET AI L A FOR OPTIO N 2)

0.030

0.020 DIA

0.010

0.108

0.100

0.092

111808-C

Rev. A | Page 14 of 16

ADXL001

NOTES

Rev. A | Page 15 of 16

ADXL001

NOTES

Rev. A | Page 16 of 16

ANALOG DEVICES ADXL001 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

FEATURES

APPLICATIONS

GENERAL DESCRIPTION

FUNCTIONAL BLOCK DIAGRAM

TABLE OF CONTENTS

REVISION HISTORY

SPECIFICATIONS

SPECIFICATIONS FOR 3.3 V OPERATION

SPECIFICATIONS FOR 5 V OPERATION

RECOMMENDED SOLDERING PROFILE

Soldering Profile Diagram

ABSOLUTE MAXIMUM RATINGS

ESD CAUTION

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

TYPICAL PERFORMANCE CHARACTERISTICS

THEORY OF OPERATION

DESIGN PRINCIPLES

MECHANICAL SENSOR

APPLICATIONS INFORMATION

APPLICATION CIRCUIT

SELF-TEST

ACCELERATION SENSITIVE AXIS

OPERATING VOLTAGES OTHER THAN 5 V

LAYOUT, GROUNDING, AND BYPASSING CONSIDERATIONS

CLOCK FREQUENCY SUPPLY RESPONSE

POWER SUPPLY DECOUPLING

ELECTROMAGNETIC INTERFERENCE

OUTLINE DIMENSIONS

ORDERING GUIDE