ANALOG DEVICES ADXRS642 Service Manual

Vibration Rejecting ±250°/s Yaw Rate Gyroscope

FEATURES

Complete rate gyroscope on a single chip
Z-axis (yaw rate) response
20°/hour bias stability

0.02°/√second angle random walk
High vibration rejection over a wide frequency
10,000 g powered shock survivability
Ratiometric to referenced supply
5 V single supply operation

−40°C to +105°C operation
Self-test on digital command
Ultrasmall and light (<0.15 cc, <0.5 gram)
Temperature sensor output
RoHS compliant

APPLICATIONS

Industrial applications
Inertial measurement units
Severe mechanical environments
Platform stabilization

GENERAL DESCRIPTION

The ADXRS642 is a complete angular rate sensor (gyroscope)
that uses the Analog Devices, Inc., surface-micromachining
process to make a functionally complete and low cost angular rate
sensor integrated with all of the required electronics on one chip.
The manufacturing technique for this device is a patented high
volume BiMOS process with years of proven field reliability.

The ADXRS642 is an industrial grade gyroscope that is 100%
pin, package, temperature, and function compatible with the

ADXRS622 and ADXRS652, while offering enhanced vibration

rejection

The output signal, RATEOUT (1B, 2A), is a voltage propor­tional to angular rate about the axis normal to the top surface
of the package. The measurement range is a minimum of
±250°/s. The output is ratiometric with respect to a provided
reference supply. Other external capacitors are required for
operation.

A temperature output is provided for compensation techniques.
Two digital self-test inputs electromechanically excite the sensor
to test proper operation of both the sensor and the signal condi­tioning circuits. The ADXRS642 is available in a 7 mm × 7 mm ×
3 mm BGA chip-scale package.

FUNCTIONAL BLOCK DIAGRAM

3V TO 5V

(ADC REF)

ADXRS642

100nF

5V

AV

CC

100nF

AGND

DRIVE

5V

V

DD

100nF

PGND

CP1 CP2 CP3 CP4 CP5 SUMJ RATEOUT

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 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.

ST2 ST1 TEMP V

SELF-TEST

MECHANICAL

AMP

SENSOR

CHARGE PUMP

AND VOLTAGE

REGULATOR

22nF

22nF

RATIO

25kΩ

@ 25°C

100nF

Figure 1.

25kΩ

AC

AMP

180kΩ ±1%

C

OUT

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2011 Analog Devices, Inc. All rights reserved.

VGA

ADXRS642

DEMOD

09770-001

ADXRS642

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1

General Description ......................................................................... 1

Functional Block Diagram .............................................................. 1

Revision History ............................................................................... 2

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

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

Rate Sensitive Axis ....................................................................... 4

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

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

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

REVISION HISTORY

4/11—Revision 0: Initial Version

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

Setting Bandwidth .........................................................................8

Temperature Output and Calibration .........................................8

Supply Ratiometricity ...................................................................8

Modifying the Measurement Range ...........................................9

Null Adjustment ............................................................................9

Self-Test Function .........................................................................9

Continuous Self-Tes t .....................................................................9

Mechanical Performance ..............................................................9

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

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

Rev. 0 | Page 2 of 12

ADXRS642

SPECIFICATIONS

All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed. TA = 25°C, VS = AVCC = VDD = 5 V,

= AVCC, angular rate = 0°/sec, bandwidth = 80 Hz (C

V

RAT IO

Table 1.

Parameter Conditions Min Typ Max Unit

SENSITIVITY1 Clockwise rotation is positive output

Measurement Range2 Full-scale range over specifications range ±250 ±300 °/sec
Initial and Over Temperature

−40°C to +105°C 7.0 mV/°/sec
Temperature Drift3 ±2 %
Nonlinearity Best fit straight line 0.01 % of FS

NULL1

Null −40°C to +105°C 2.5 V
Calibrated Null4 −40°C to +105°C ±0.1 °/sec
Temperature Drift −40°C to +105°C ±1 °/sec
Linear Acceleration Effect Any axis 0.03 °/sec/g
Vibration Rectification 25 g rms, 50 Hz to 5 kHz 0.0002 °/s/g2

NOISE PERFORMANCE

Rate Noise Density TA ≤ 25°C 0.02 °/sec/√Hz
Resolution Floor

T

= 25°C 1 minute to 1 hour in-run

A

FREQUENCY RESPONSE

Bandwidth

5

+3 dB user adjustable up to specification 2000 Hz

Sensor Resonant Frequency 15 17 19 kHz

SELF-TEST1

ST1 RATEOUT Response

ST1 pin from Logic 0 to Logic 1 −45 °/sec
ST2 RATEOUT Response ST2 pin from Logic 0 to Logic 1 45 °/sec
ST1 to ST2 Mismatch6 −5
Logic 1 Input Voltage 3.3 V
Logic 0 Input Voltage 1.7 V
Input Impedance To common 40 50 100 kΩ

TEMPERATURE SENSOR1

V

at 25°C Load = 10 MΩ 2.35 2.5 2.65 V

OUT

Scale Factor7 25°C, V
Load to V

S

25 kΩ

= 5 V 9 mV/°C

RAT IO

Load to Common 25 kΩ

TURN-ON TIME4 Power on to ±0.5°/sec of final with CP5 = 100 nF 50 ms
OUTPUT DRIVE CAPABILITY

Current Drive For rated specifications 200 µA
Capacitive Load Drive 1000 pF

POWER SUPPLY

Operating Voltage (VS) 4.75 5.00 5.25 V
Quiescent Supply Current 3.5 4.5 mA

TEMPERATURE RANGE

Specified Performance −40 +105 °C

1

Parameter is linearly ratiometric with V

2

Measurement range is the maximum range possible, including output swing range, initial offset, sensitivity, offset drift, and sensitivity drift at 5 V supplies.

3

From +25°C to −40°C or +25°C to +105°C.

4

Based on characterization.

5

Adjusted by external capacitor, C

6

Self-test mismatch is described as (ST2 + ST1)/((ST2 − ST1)/2).

7

Scale factor for a change in temperature from 25°C to 26°C. V

.

RATIO

. Reducing bandwidth below 0.01 Hz does not result in further noise improvement.

OUT

is ratiometric to V

TEMP

= 0.01 µF), I

OUT

= 100 µA, ±1 g, unless otherwise noted.

OUT

20 °/hr

. See the Temperature Output and Calibration section for more information.

RATIO

±2 +5

%

Rev. 0 | Page 3 of 12

ADXRS642

RATE

AXIS

LONGITUDINAL

AXIS

LATERAL AX IS

+

A B C D G

1

7

E F

A1

RATE OUT

RATE IN

4.75V

0.25V

VCC = 5V

V

RATIO

/2

GND

09770-002

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

Acceleration (Any Axis, 0.5 ms)

Unpowered 10,000 g
Powered 10,000 g

VDD, AV

CC

V

AVCC

RAT IO

−0.3 V to +6.0 V

ST1, ST2 AVCC
Output Short-Circuit Duration

Indefinite

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

Stresses above those listed under the 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.

Drops onto hard surfaces can cause shocks of greater than
10,000 g and can exceed the absolute maximum rating of the
device. Care should be exercised in handling to avoid damage.

RATE SENSITIVE AXIS

This is a z-axis rate-sensing device (also called a yaw rate­sensing device). It produces a positive going output voltage
for clockwise rotation about the axis normal to the package
top, that is, clockwise when looking down at the package lid.

Figure 2. RATEOUT Signal Increases with Clockwise Rotation

ESD CAUTION

Rev. 0 | Page 4 of 12