ADXRS642 [ADI]
Vibration Rejecting ±250°/s Yaw Rate Gyro; 振动拒绝± 250 ° /秒偏航角速度陀螺仪
| 型号： | ADXRS642 |
| 厂家： | 
ADI |
| 描述： | Vibration Rejecting ±250°/s Yaw Rate Gyro |
| 文件： | 总10页 (文件大小：191K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Vibration Rejecting ± ±250°/ ꢀaꢁ Rate ꢂGro
ADXRS64±
PreliminarG Technical Data
FEATURES
GENERAL DESCRIPTION
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 wide frequency
10,000 g powered shock survivability
Ratiometric to referenced supply
5 V single-supply operation
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
−40°C to +105°C operation
Self-test on digital command
Ultrasmall and light (<0.15 cc, <0.5 gram)
Temperature sensor output
The output signal, RATEOUT (1B, 2A), is a voltage propor-
tional to angular rate about the axis normal to the top surface
of the package. The measurement range is a minimum of
250ꢀ°s. The output is ratiometric with respect to a provided
reference supply. Other external capacitors are required for
operation.
RoHS compliant
APPLICATIONS
Industrial applications
Inertial Measurement Units
Severe Mechanical Environments
Platform stabilization
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 condi-
tioning circuits. The ADXRS642 is available in a 7 mm × 7 mm ×
3 mm BGA chip-scale package.
FUNCTIONAL BLOCK DIAGRAM
3 to 5V
(ADC REF)
100nF
5V
ST2 ST1
TEMP
V
RATIO
AV
CC
ADXRS642
25k
SELF-TEST
25k
@ 25°C
100nF
AGND
DEMOD
AC
AMP
DRIVE
AMP
MECHANICAL
SENSOR
VGA
5V
180k ±1%
V
DD
CHARGE PUMP
AND VOLTAGE
REGULATOR
100nF
PGND
CP1
SUMJ
100nF
RATEOUT
CP2 CP3
CP4 CP5
C
OUT
22nF
22nF
08820-001
Figure 1. Block Diagram
Rev. Pr 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 registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©201 Analog Devices, Inc. All rights reserved.
ADXRS64±
PreliminarG Technical Data
TABLE OF CONTENTS
Features .............................................................................................. 1
Setting Bandwidth.........................................................................6
Temperature Output and Calibration.........................................6
Supply Ratiometricity ...................................................................6
Modifying the measurement range.............................................7
Null Adjustment ............................................................................8
Self-Test Function .........................................................................8
Continuous Self-Test.....................................................................8
mechanical performance..............................................................8
Outline Dimensions..........................................................................9
Ordering Guide .............................................................................9
Applications....................................................................................... 1
General Description......................................................................... 1
Functional Block Diagram .............................................................. 1
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
Rate Sensitive Axis ....................................................................... 4
ESD Caution.................................................................................. 4
Pin Configuration and Function Descriptions............................. 5
Theory of Operation ........................................................................ 6
Rev. Pr. A | Page 2 of 10
PreliminarG Technical Data
ADXRS64±
SPECIFICATIONS
All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed.
TA = 25ꢀC, VS = AVCC = VDD = 5 V, VRATIO = AVCC, angular rate = 0ꢀ°sec, bandwidth = 80 Hz (COUT = 0.01 μF), IOUT = 100 μA,
1 g, unless otherwise noted.
Table 1.
Parameter
Conditions
Min
2ꢀ0
Typ
300
7.0
2
Max
Unit
SENSITIVITY1
Clockwise rotation is positive output
Full-scale range over specifications range
−40°C to +10ꢀ°C
Measurement Range2
Initial and Over Temperature
Temperature Drift3
Nonlinearity
°/sec
mV/°/sec
%
Best fit straight line
0.01
% of FS
NULL1
Null
−40°C to +10ꢀ°C
−40°C to +10ꢀ°C
−40°C to +10ꢀ°C
Any axis
2.ꢀ
0.1
1
0.03
0.0002
V
Calibrated Null7
°/sec
°/sec
°/sec/g
°/s/g2
Temperature Drift
Linear Acceleration Effect
Vibration Rectification
NOISE PERFORMANCE
Rate Noise Density
Resolution Floor
FREQUENCY RESPONSE
Bandwidth4
2ꢀg RMS, ꢀ0Hz to ꢀkHz
TA ≤ 2ꢀ°C
0.02
20
°/sec/√Hz
°/hr
TA = 2ꢀ°C 1 minute to 1 hour in-run
+3dB user adjustable up to
2000
18
Hz
kHz
Sensor Resonant Frequency
SELF-TEST1
16
20
ST1 RATEOUT Response
ST2 RATEOUT Response
ST1 to ST2 Mismatchꢀ
Logic 1 Input Voltage
Logic 0 Input Voltage
Input Impedance
TEMPERATURE SENSOR1
VOUT at 2ꢀ°C
ST1 pin from Logic 0 to Logic 1
ST2 pin from Logic 0 to Logic 1
-4ꢀ
4ꢀ
2
°/sec
°/sec
%
V
V
-ꢀ
3.3
ꢀ
1.7
100
To common
40
ꢀ0
kΩ
Load = 10 MΩ
2ꢀ°C, VRATIO = ꢀ V
2.3ꢀ
2.ꢀ
9
2ꢀ
2ꢀ
2.6ꢀ
ꢀ0
V
Scale Factor6
mV/°C
kΩ
kΩ
Load to VS
Load to Common
TURN-ON TIME7
Power on to 0.ꢀ°/s of final with CPꢀ = 100nF
For rated specifications
ms
OUTPUT DRIVE CAPABILITY
Current Drive
Capacitive Load Drive
POWER SUPPLY
200
1000
μA
pF
Operating Voltage (VS)
Quiescent Supply Current
TEMPERATURE RANGE
Specified Performance
4.7ꢀ
−40
ꢀ.00
3.ꢀ
ꢀ.2ꢀ
4.ꢀ
V
mA
+10ꢀ
°C
1 Parameter is linearly ratiometric with VRATIO
.
2 Measurement range is the maximum range possible, including output swing range, initial offset, sensitivity, offset drift, and sensitivity drift at ꢀ V supplies.
3 From +2ꢀ°C to −40°C or +2ꢀ°C to +10ꢀ°C.
4 Adjusted by external capacitor, COUT. Reducing bandwidth below 0.01 Hz does not result in further noise improvement.
ꢀ Self-test mismatch is described as (ST2 + ST1)/((ST2 − ST1)/2).
6 Scale factor for a change in temperature from 2ꢀ°C to 26°C. VTEMP is ratiometric to VRATIO. See the Temperature Output and Calibration section for more information.
7 Based on characterization
Rev. Pr. A | Page 3 of 10
ADXRS64±
PreliminarG Technical Data
ABSOLUTE MAXIMUM RATINꢂS
RATE SENSITIVE AXIS
Table 2.
This is a Z-axis rate-sensing device (also called a yaw rate-
sensing 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.
Parameter
Acceleration (Any Axis, 0.ꢀ ms)
Unpowered
Powered
VDD, AVCC
VRATIO
ST1, ST2
Output Short-Circuit Duration
(Any Pin to Common)
Operating Temperature Range
Storage Temperature Range
Rating
3,000 g
3,000 g
−0.3 V to +6.0 V
AVCC
AVCC
Indefinite
RATE
AXIS
RATE OUT
V
7
= 5V
CC
LONGITUDINAL
AXIS
4.75V
+
1
V
/2
−ꢀꢀ°C to +12ꢀ°C
−6ꢀ°C to +1ꢀ0°C
RATIO
RATE IN
0.25V
A B C D E F G
LATERAL AXIS
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.
A1
GND
Figure 2. RATEOUT Signal Increases with Clockwise Rotation
ESD CAUTION
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.
Rev. Pr. A | Page 4 of 10
PreliminarG Technical Data
ADXRS64±
PIN CONFIꢂURATION AND FUNCTION DESCRIPTIONS
V
CP5
CP3
DD
CP4
PGND
7
6
5
4
3
2
1
CP1
ST1
CP2
ST2
AV
TEMP
CC
AGND
RATEOUT
V
NC
D
SUMJ
C
RATIO
G
F
E
B
A
Figure 3. Pin Configuration
Table 3. Pin Function Descriptions
Pin No.
6D, 7D
6A, 7B
6C, 7C
ꢀA, ꢀB
4A, 4B
3A, 3B
1B, 2A
1C, 2C
1D, 2D
1E, 2E
1F, 2G
3F, 3G
4F, 4G
ꢀF, ꢀG
6G, 7F
6E, 7E
Mnemonic
Description
CPꢀ
CP4
CP3
CP1
CP2
AVCC
RATEOUT
SUMJ
NC
VRATIO
AGND
TEMP
ST2
ST1
PGND
VDD
HV Filter Capacitor, 100nF.
Charge Pump Capacitor, 22 nF.
Charge Pump Capacitor, 22 nF.
Charge Pump Capacitor, 22 nF.
Charge Pump Capacitor, 22 nF.
Positive Analog Supply.
Rate Signal Output.
Output Amp Summing Junction.
Do Not Connect.
Reference Supply for Ratiometric Output.
Analog Supply Return.
Temperature Voltage Output.
Self-Test for Sensor 2.
Self-Test for Sensor 1.
Charge Pump Supply Return.
Positive Charge Pump Supply.
Rev. Pr. A | Page ꢀ of 10
ADXRS64±
PreliminarG Technical Data
THEORꢀ OF OPERATION
The ADXRS642 operates on the principle of a resonator gyro.
Figure 4 shows a simplified version of one of four polysilicon
sensing structures. Each sensing structure contains a dither
frame that is electrostatically driven to resonance. This
produces the necessary velocity element to produce a Coriolis
force when experiencing angular rate. The ADXRS642 is
designed to sense a Z-axis (yaw) angular rate.
SETTING BANDWIDTH
External Capacitor COUT is used in combination with the on-
chip ROUT resistor to create a low-pass filter to limit the bandwidth
of the ADXRS642 rate response. The −3 dB frequency set by
ROUT and COUT is
fOUT 1°
2 π ROUT COUT
and can be well controlled because ROUT has been trimmed
during manufacturing to be 180 kΩ 1%. Any external resistor
applied between the RATEOUT pin (1B, 2A) and SUMJ pin
(1C, 2C) results in
When the sensing structure is exposed to angular rate, the
resulting Coriolis force couples into an outer sense frame,
which contains movable fingers that are placed between fixed
pickoff fingers. This forms a capacitive pickoff structure that
senses Coriolis motion. The resulting signal is fed to a series of
gain and demodulation stages that produce the electrical rate
signal output. The quad sensor design rejects linear and angular
acceleration, including external g-forces and vibration. This is
achieved by mechanically coupling the four sensing structures
such that external g-forces appear as common-mode signals
that can be removed by the fully differential architecture
implemented in the ADXRS642.
ROUT
180 kꢁ REXT
°
180 kꢁ REXT
In general, an additional filter (in either hardware or software)
is added to attenuate high frequency noise arising from demodu-
lation spikes at the 18 kHz resonant frequency of the gyro. An
R°C output filter consisting of a 3.3k series resistor and 22nF
shunt capacitor (2.2kHz pole) is recommended.
TEMPERATURE OUTPUT AND CALIBRATION
It is common practice to temperature-calibrate gyros to improve
their overall accuracy. The ADXRS642 has a temperature propor-
tional voltage output that provides input to such a calibration
method. The temperature sensor structure is shown in Figure .
The temperature output is characteristically nonlinear, and any
load resistance connected to the TEMP output results in decreasing
the TEMP output and its temperature coefficient. Therefore,
buffering the output is recommended.
X
Y
Z
The voltage at TEMP (3F, 3G) is nominally 2.5 V at 25ꢀC, and
VRATIO = 5 V. The temperature coefficient is ~9 mV°ꢀC at 25ꢀC.
Although the TEMP output is highly repeatable, it has only
modest absolute accuracy.
V
RATIO
V
TEMP
R
R
FIXED
TEMP
Figure 5. Temperature Sensor Structure
Figure 4. Simplified Gyro Sensing Structure – One Corner
SUPPLY RATIOMETRICITY
The electrostatic resonator requires 18 to 20V for operation.
Because only 5V are typically available in most applications,
a charge pump is included on chip. If an external 18 to 20V
supply is available, the two capacitors on CP1 to CP4 can be
omitted, and this supply can be connected to CP5 (Pin 6D,
Pin 7D). CP5 should not be grounded when power is applied to
the ADXRS642. No damage occurs, but under certain conditions,
the charge pump may fail to start up after the ground is removed
without first removing power from the ADXRS642.
The AD642’s RATEOUT, ST1, ST2, and TEMP signals are
ratiometric to the VRATIO voltage, i.e., the null voltage, rate
sensitivity, and temperature outputs are proportional to VRATIO
So, it is most easily used with a supply-ratiometric ADC which
results in self cancellation of errors due to minor supply
variations. There is some small, usually negligible, error due to
non-ratiometric behavior. Note that, in order to guarantee full
rate range, VRATIO should not be greater than AVCC
.
Rev. Pr. A | Page 6 of 10
PreliminarG Technical Data
ADXRS64±
MODIFYING THE MEASUREMENT RANGE
The ADXRS642 scale factor can be reduced to extend the
measurement range to as much as 450ꢀ°s by adding a single
225kΩ resistor between the RATEOUT and SUMJ. If an
external resistor is added between RATEOUT and SUMJ COUT
must be proportionally reduced to maintain correct bandwidth.
Rev. Pr. A | Page 7 of 10
ADXRS64±
PreliminarG Technical Data
response with and without 15g RMS 50Hz to 5kHz of random
vibration. Bandwidth of the gyro was limited to 1600Hz.
Performance is similar regardless of the direction of input
vibration.
NULL ADJUSTMENT
The nominal 2.5 V null is for a symmetrical swing range at
RATEOUT (1B, 2A). However, a nonsymmetric output swing
may be suitable in some applications. Null adjustment is possible
by injecting a suitable current to SUMJ (1C, 2C). Note that supply
disturbances may reflect some null instability. Digital supply noise
should be avoided, particularly in this case.
1
0.1
0.01
SELF-TEST FUNCTION
0.001
0.0001
0.00001
The ADXRS642 includes a self-test feature that actuates each of
the sensing structures and associated electronics in the same
manner, as if subjected to angular rate. It is activated by standard
logic high levels applied to Input ST1 (5F, 5G), Input ST2
(4F, 4G), or both. ST1 causes the voltage at RATEOUT to change
about −0.3 V, and ST2 causes an opposite change of +0.3 V. The
self-test response follows the viscosity temperature dependence
of the package atmosphere, approximately 0.25%°ꢀC.
10
100
1000
10000
Frequency
Figure 6. ADXRS642 Output Response With and Without Random Vibration
(15g RMS, 50Hz to 5kHz)
Activating both ST1 and ST2 simultaneously is not damaging.
ST1 and ST2 are fairly closely matched ( 2%), but actuating
both simultaneously may result in a small apparent null bias
shift proportional to the degree of self-test mismatch.
Figure 7 demonstrates the ADXRS642 DC bias response to 5g
Sine vibration over the 20Hz to 5kHz range. As can be seen,
there are no sensitive frequencies present and vibration
rectification is vanishingly small. As in the previous example
gyro bandwidth was set to 1600Hz.
ST1 and ST2 are activated by applying a voltage equal to VRATIO
to the ST1 pin and the ST2 pin. The voltage applied to ST1 and
ST2 must never be greater than AVCC
.
0.12
0.1
CONTINUOUS SELF-TEST
0.08
0.06
0.04
0.02
0
The on-chip integration of the ADXRS642 gives it higher reliability
than is obtainable with any other high volume manufacturing
method. Also, it is manufactured under a mature BiMOS process
that has field-proven reliability. As an additional failure detection
measure, power-on self-test can be performed. However, some
applications may warrant continuous self-test while sensing rate.
Details outlining continuous self-test techniques are also
available in the AN-768 Application Note.
‐0.02
‐0.04
10
100
1000
10000
Hz
Figure 7. ADXRS642 Sine Vibration Output Response (5g, 20Hz to 5kHz)
MECHANICAL PERFORMANCE
The ADXRS642 excellent vibration rejection is demonstrated in
the graphs below. Figure 6 shows the ADXRS642 output
Rev. Pr. A | Page 8 of 10
PreliminarG Technical Data
OUTLINE DIMENSIONS
ADXRS64±
7.05
6.85 SQ
6.70
*
A1 CORNER
INDEX AREA
A1 BALL
CORNER
7
6
5
4
3
2
1
A
B
C
D
E
F
4.80
BSC SQ
0.80
BSC
G
TOP VIEW
DETAIL A
BOTTOM VIEW
DETAIL A
3.80 MAX
3.20 MAX
2.50 MIN
0.60 MAX
0.25 MIN
0.60
0.55
0.50
COPLANARITY
0.15
SEATING
PLANE
BALL DIAMETER
*
BALL A1 IDENTIFIER IS GOLD PLATED AND CONNECTED
TO THE D/A PAD INTERNALLY VIA HOLES.
Figure 8. 32-Lead Ceramic Ball Grid Array [CBGA]
(BC-32-3)
Dimensions shown in millimeters
ORDERING GUIDE
Model1
ADXRS642BBGZ
ADXRS642BBGZ-RL
EVAL-ADXRS642Z
Temperature Range
–40°C to +10ꢀ°C
–40°C to +10ꢀ°C
Package Description
Package Option
32-Lead Ceramic Ball Grid Array [CBGA]
32-Lead Ceramic Ball Grid Array [CBGA]
Evaluation Board
BC-32-3
BC-32-3
1 Z = RoHS Compliant Part.
Rev. Pr. A | Page 9 of 10
ADXRS642
NOTES
Preliminary Technical Data
©2011 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
PR09770-0-2/11(PrA)
Rev. PrA | Page 10 of 10
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