300/s Single Chip Yaw Rate
Gyro with Signal Conditioning
ADXRS300
FEATURES
Complete rate gyroscope on a single chip
Z-axis (yaw rate) response
High vibration rejection over wide frequency
2000 g powered shock operation
Self-test on digital command
Temperature sensor output
Precision voltage reference output
Absolute rate output for precision applications
5 V single-supply operation
Ultrasmall and light (< 0.15 cc, < 0.5 gram)
APPLICATIONS
Vehicle chassis rollover sensing
Inertial measurement units
Platform stabilization
GENERAL DESCRIPTION
The ADXRS300 is a complete angular rate sensor (gyroscope)
that uses Analog Devices' 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 the same high vol-
ume BIMOS process used for high reliability automotive airbag
accelerometers.
The output signal, RATEOUT (1B, 2A), is a voltage proportional
to angular rate about the axis normal to the top surface of the
package (see Figure 3). A single external resistor can be used to
lower the scale factor. An external capacitor is used to set the
bandwidth. Other external capacitors are required for operation
(see Figure 4).
A precision reference and a temperature output are also pro-
vided for compensation techniques. Two digital self-test inputs
electromechanically excite the sensor to test proper operation of
both sensors and the signal conditioning circuits. The
ADXRS300 is available in a 7 mm 7 mm 3 mm BGA
chip-scale package.
FUNCTIONAL BLOCK DIAGRAM
5G
4G
3A
5V
2G
1F
7F
6A
7D
7C
7B
1C
4A
5A
7E
6G
1D
2A
1E
3G
1B
PDD
12V
+
ADXRS300
47nF
22nF
100nF
22nF
CP2
CP1
PGND
CP4
CP3
CP5
CHARGE PUMP/REG.
TEMP
PTAT
RATEOUT
2.5V
DEMOD
RATE
SENSOR
SELF
TEST
100nF
100nF
CMID
AGND
AVCC
ST1
ST2
CORIOLIS SIGNAL CHANNEL
R
SEN1
R
SEN2
C
OUT
SUMJ
R
OUT
2.5V REF
7k 35% 7k 35%
180k
1%
RESONATOR LOOP
Figure 1.
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.326.8703
2003 Analog Devices, Inc. All rights reserved.
ADXRS300
TABLE OF CONTENTS
ADXRS300--Specifications ............................................................ 3
Absolute Maximum Ratings............................................................ 4
Rate Sensitive Axis........................................................................ 4
Theory of Operation ........................................................................ 5
Supply and Common Considerations ....................................... 5
Setting Bandwidth ........................................................................ 5
Increasing Measurement Range ................................................. 6
Using the ADXRS300 with a Supply-Ratiometric ADC ..........6
Null Adjust .....................................................................................6
Self-Test Function .........................................................................6
Continuous Self-Test.....................................................................6
Pin Configurations And Functional Descriptions ........................7
Outline Dimensions ..........................................................................8
REVISION HISTORY
Revision A
3/03--Data Sheet Changed from REV. 0 to REV. A
Edit to Figure 3...................................................................................5
Rev. A | Page 2 of 8
ADXRS300
ADXRS300--SPECIFICATIONS
Table 1. @T
A
= 25C, V
S
= 5 V, Angular Rate = 0/s, Bandwidth = 80 Hz (C
OUT
= 0.01 F), unless otherwise noted.
ADXRS300ABG
Parameter Conditions
Min
1
Typ Max
1
Unit
SENSITIVITY Clockwise
Rotation Is Positive Output
Dynamic Range
2
Full-Scale Range over Specifications Range
300
/s
Initial @25C
4.6
5
5.4
mV//s
Over Temperature
3
V
S
= 4.75 V to 5.25 V
4.6
5
5.4
mV//s
Nonlinearity
Best Fit Straight Line
0.1
% of FS
NULL
Initial Null
2.3
2.50
2.7
V
Over Temperature
3
V
S
= 4.75 V to 5.25 V
2.3
2.7
V
Turn-On Time
Power on to /s of Final
35
ms
Linear Acceleration Effect
Any Axis
0.2
/s/g
Voltage Sensitivity
V
CC
= 4.75 V to 5.25 V
1
/s/V
NOISE
PERFORMANCE
Rate Noise Density
@25C
0.1
/s/
Hz
FREQUENCY
RESPONSE
3 dB Bandwidth (User Selectable)
4
22 nF as Comp Cap (see Setting Bandwidth section)
40
Hz
Sensor Resonant Frequency
14
kHz
SELF-TEST
INPUTS
ST1 RATEOUT Response
5
ST1 Pin from Logic 0 to 1
150
270
450
mV
ST2 RATEOUT Response
5
ST2 Pin from Logic 0 to 1
+150
+270
+450
mV
Logic 1 Input Voltage
Standard High Logic Level Definition
3.3
V
Logic 0 Input Voltage
Standard Low Logic Level Definition
1.7
V
Input Impedance
To Common
50
k
TEMPERATURE
SENSOR
V
OUT
at 298K
2.50
V
Max Current Load on Pin
Source to Common
50
A
Scale Factor
Proportional to Absolute Temperature
8.4
mV/K
OUTPUT
DRIVE
CAPABILITY
Output Voltage Swing
I
OUT
= 100 A
0.25
V
S
0.25
V
Capacitive Load Drive
1000
pF
2.5 V REFERENCE
Voltage Value
2.45
2.5
2.55
V
Load Drive to Ground
Source
200
A
Load Regulation
0 < I
OUT
< 200 A
5.0
mV/mA
Power Supply Rejection
4.75 V
S
to 5.25 V
S
1.0
mV/V
Temperature Drift
Delta from 25C
5.0
mV
POWER
SUPPLY
Operating Voltage Range
4.75
5.00
5.25
V
Quiescent Supply Current
6.0
8.0
mA
TEMPERATURE
RANGE
Specified Performance Grade A
Temperature Tested to Max and Min Specs.
40
+85
C
1
All min and max specifications are guaranteed. Typical specifications are not tested or guaranteed.
2
Dynamic range is the maximum full-scale measurement range possible, including output swing range, initial offset, sensitivity, offset drift, and sensitivity drift at
5 V supplies.
3
Specification refers to the maximum extent of this parameter as a worst-case value of T
MIN
or T
MAX
.
4
Frequency at which response is 3 dB down from dc response with specified compensation capacitor value. Internal pole forming resistor is 180 k. See
section.
Setting Band-
width
5
Self-test response varies with temperature. Refer to the
section for details.
Self-Test Function
Rev. A | Page 3 of 8
ADXRS300
ABSOLUTE MAXIMUM RATINGS
Table 2. ADXRS300 Absolute Maximum Ratings
Parameter Rating
Acceleration (Any Axis, Unpowered, 0.5 ms)
2000 g
Acceleration (Any Axis, Powered, 0.5 ms)
2000 g
+V
S
0.3 V to +6.0 V
Output Short-Circuit Duration
(Any Pin to Common)
Indefininte
Operating Temperature Range
55C to +125C
Storage Temperature
65C to +150C
Stresses above those listed under the Absolute Maximum Rat-
ings 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 sec-
tion of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Applications requiring more than 200 cycles to MIL-STD-883
Method 1010 Condition B (55C to +125C) require underfill
or other means to achieve this requirement.
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.
Rate Sensitive Axis
This is a Z-axis rate-sensing device that is 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, i.e.,
clockwise when looking down at the package lid.
2.5V
RATE
AXIS
RATEOUT
RATE IN
GND
4.75V
0.25V
LATERAL AXIS
A B C D E F G
7
A1
1
LONGITUDINAL
AXIS
V
CC
= 5V
Figure 2. RATEOUT Signal Increases with Clockwise Rotation
Rev. A | Page 4 of 8
ADXRS300
Rev. A | Page 5 of 8
THEORY OF OPERATION
The ADXRS300 operates on the principle of a resonator gyro.
Two polysilicon sensing structures each contain a dither frame,
which is electrostatically driven to resonance. This produces the
necessary velocity element to produce a Coriolis force during
angular rate. At two of the outer extremes of each frame,
orthogonal to the dither motion, are movable fingers that are
placed between fixed pickoff fingers to form 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 dual-sensor design rejects
external g-forces and vibration. Fabricating the sensor with the
signal conditioning electronics preserves signal integrity in
noisy environments.
The electrostatic resonator requires 14 V to 16 V for operation.
Since only 5 V is typically available in most applications, a
charge pump is included on-chip. If an external 14 V to 16 V
supply is available, the two capacitors on CP1CP4 can be omit-
ted and this supply can be connected to CP5 (Pin 7D) with a
100 nF decoupling capacitor in place of the 47 nF.
After the demodulation stage there is a single-pole low-pass
filter consisting of an internal 7 k resistor (R
SEN1
) and an
external user-supplied capacitor (CMID). A CMID capacitor of
100 nF sets a 400 Hz 35% low-pass pole and is used to limit
high frequency artifacts before final amplification. Bandwidth
limit capacitor, C
OUT
, sets the pass bandwidth (see Figure 4 and
the Setting Bandwidth section).
AGND
TEMP
ST2
ST1
CP1
CP2
RATEOUT
CP4
PDD
CMID
SUMJ
2.5V
6A
5A
4A
3A
2A
1B
1C
1D
1E
1F
7B
7C
7D
7E
7F
6G
5G
4G
3G
2G
CP5
CP3
100nF
C
OUT
= 22nF
22nF
AVCC
100nF
100nF
PGND
22nF
47nF
5V
NOTE THAT INNER ROWS/COLUMNS OF PINS HAVE BEEN OMITTED
FOR CLARITY BUT SHOULD BE CONNECTED IN THE APPLICATION.
Figure 3. Example Application Circuit (Top View)
Supply and Common Considerations
Only power supplies used for supplying analog circuits are rec-
ommended for powering the ADXRS300. High frequency noise
and transients associated with digital circuit supplies may have
adverse effects on device operation.
Figure 3 shows the recommended connections for the
ADXRS300 where both AVCC and PDD have a separate
decoupling capacitor. These should be placed as close to the
their respective pins as possible before routing to the system
analog supply. This will minimize the noise injected by the
charge pump that uses the PDD supply.
It is also recommended to place the charge pump capacitors
connected to the CP1CP4 pins as close to the part as possible.
These capacitors are used to produce the on-chip high voltage
supply switched at the dither frequency at approximately
14 kHz. Care should be taken to ensure that there is no more
than 50 pF of stray capacitance between CP1CP4 and ground.
Surface-mount chip capacitors are suitable as long as they are
rated for over 15 V.
5V
+
-
SELF
TEST
AVCC
ST1
ST2
3A
5G
4G
ADXRS300
CP2
CP1
PDD
4A 5A
7E 6G
CHARGE
PUMP/REG.
12V
PTAT
7F
6A 7B 7C
7D
47nF
CP4 CP3 CP5
RATE
SENSOR
2G 1F
1D
CORIOLIS
SIGNAL CHANNEL
AGND
CMID
1C
SUMJ
RATE-
OUT
2.5V
1B
2A
1E
3G TEMP
R
OUT
180k
1%
RESONATOR LOOP
DEMOD
2.5V REF
7k 35%
100nF
22nF
100nF
100nF
C
OUT
R
SEN1
R
SEN2
22nF
PGND
Figure 4. Block Diagram with External Components
Setting Bandwidth
External capacitors CMID and C
OUT
are used in combination
with on-chip resistors to create two low-pass filters to limit the
bandwidth of the ADXRS300's rate response. The 3 dB fre-
quency set by R
OUT
and C
OUT
is
(
)
OUT
OUT
OUT
C
R
/
f
=
2
1
and can be well controlled since R
OUT
has been trimmed during
manufacturing to be 180 k 1%. Any external resistor applied
ADXRS300
between the RATEOUT (1B, 2A) and SUMJ (1C, 2C) pins will
result in
(
) (
)
EXT
EXT
OUT
R
k
/
R
k
R
=
180
180
The 3 dB frequency is set by RSEN (the parallel combination
of R
SEN1
and R
SEN2
) at about 3.5 k nominal; CMID is less well
controlled since R
SEN1
and R
SEN2
have been used to trim the rate
sensitivity during manufacturing and have a 35% tolerance. Its
primary purpose is to limit the high frequency demodulation
artifacts from saturating the final amplifier stage. Thus, this pole
of nominally 400 Hz @ 0.1 F need not be precise. Lower fre-
quency is preferable, but its variability usually requires it to be
about 10 times greater (in order to preserve phase integrity)
than the well-controlled output pole. In general, both 3 dB
filter frequencies should be set as low as possible to reduce the
amplitude of these high frequency artifacts and to reduce the
overall system noise.
Increasing Measurement Range
The full-scale measurement range of the ADXRS300 can be
increased by placing an external resistor between the RATE-
OUT (1B, 2A) and SUMJ (1C, 2C) pins, which would parallel
the internal R
OUT
resistor that is factory-trimmed to 180 k. For
example, a 330 k external resistor will give ~50% increase in
the full-scale range. This is effective for up to a 4 increase in
the full-scale range (minimum value of the parallel resistor
allowed is 45 k). Beyond this amount of external sensitivity
reduction, the internal circuitry headroom requirements
prevent further increase in the linear full-scale output range.
The drawbacks of modifying the full-scale range are the addi-
tional output null drift (as much as 2/sec over temperature)
and the readjustment of the initial null bias (see the Null Adjust
section).
Using the ADXRS300 with a Supply-
Ratiometric ADC
The ADXRS300's RATEOUT signal is nonratiometric, i.e., nei-
ther the null voltage nor the rate sensitivity is proportional to
the supply. Rather they are nominally constant for dc supply
changes within the 4.75 V to 5.25 V operating range. If the
ADXRS300 is used with a supply-ratiometric ADC, the
ADXRS300's 2.5 V output can be converted and used to make
corrections in software for the supply variations.
Null Adjust
Null adjustment is possible by injecting a suitable current to
SUMJ (1C, 2C). Adding a suitable resistor to either ground or to
the positive supply is a simple way of achieving this. The nomi-
nal 2.5 V null is for a symmetrical swing range at RATEOUT
(1B, 2A). However, a nonsymmetric output swing may be suit-
able in some applications. Note that if a resistor is connected to
the positive supply, then supply disturbances may reflect some
null instabilities. Digital supply noise should be avoided
particularly in this case (see the Supply and Common
Considerations section).
The resistor value to use is approximately
)
V
)/(V
(
R
NULL
NULL
NULL
1
0
000
,
180
5
.
2
=
V
NULL0
is the unadjusted zero rate output, and V
NULL1
is the target
null value. If the initial value is below the desired value, the
resistor should terminate on common or ground. If it is above
the desired value, the resistor should terminate on the 5 V sup-
ply. Values are typically in the 1 M to 5 M range.
If an external resistor is used across RATEOUT and SUMJ, then
the parallel equivalent value is substituted into the above equa-
tion. Note that the resistor value is an estimate since it assumes
V
CC
= 5.0 V and V
SUMJ
= 2.5 V.
Self-Test Function
The ADXRS300 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 inputs ST1 (5F, 5G), ST2 (4F, 4G), or
both. ST1 will cause a voltage at RATEOUT equivalent to typi-
cally 270 mV and ST2 will cause an opposite +270 mV change.
The self-test response follows the viscosity temperature depend-
ence of the package atmosphere, approximately 0.25%/C.
Activating both ST1 and ST2 simultaneously is not damaging.
Since ST1 and ST2 are not necessarily closely matched, actuat-
ing both simultaneously may result in an apparent null bias
shift.
Continuous Self-Test
The one-chip integration of the ADXRS300 gives it higher reli-
ability than is obtainable with any other high volume manufac-
turing 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. How-
ever, some applications may warrant continuous self-test while
sensing rate. Application notes outlining continuous self-test
techniques are also available on the Analog Devices website.
Rev. A | Page 6 of 8
ADXRS300
PIN CONFIGURATIONS AND FUNCTIONAL DESCRIPTIONS
AGND
TEMP
ST2
ST1
PGND
AVCC
CP1
CP2
CP4
RATEOUT
G
F
E
D
C
B
A
7
6
5
4
3
2
1
CP5
CP3
PDD
CMID
SUMJ
2.5V
Figure 5. 32-Lead BGA (Bottom View)
Table 3. Pin Function Descriptions--32-LEAD BGA
Pin No.
Mnemonic
Description
6D, 7D
CP5
HV Filter Capacitor--47 nF
6A, 7B
CP4
6C, 7C
CP3
Charge Pump Capacitor--22 nF
5A, 5B
CP1
4A, 4B
CP2
Charge Pump Capacitor--22 nF
3A, 3B
AVCC
+ Analog Supply
1B, 2A
RATEOUT
Rate Signal Output
1C, 2C
SUMJ
Output Amp Summing Junction
1D, 2D
CMID
HF Filter Capacitor--100 nF
1E, 2E
2.5V
2.5 V Precision Reference
1F, 2G
AGND
Analog Supply Return
3F, 3G
TEMP
Temperature Voltage Output
4F, 4G
ST2
Self-Test for Sensor 2
5F, 5G
ST1
Self-Test for Sensor 1
6G, 7F
PGND
Charge Pump Supply Return
6E, 7E
PDD
+ Charge Pump Supply
Rev. A | Page 7 of 8
ADXRS300
OUTLINE DIMENSIONS
A
B
C
D
E
F
G
BOTTOM
VIEW
7
A1
6
5
4
3
TOP VIEW
DETAIL A
3.65 MAX
SEATING
PLANE
DETAIL A
BALL DIAMETER
7.00 BSC SQ
4.80 BSC
0.60
0.55
0.50
3.20
2.50
0.44
0.25
0.15 MAX
COPLANARITY
0.80
BSC
A1 CORNER
INDEX AREA
2
1
Figure 6. 32-Lead Chip Scale Ball Grid Array [CSPBGA]
(BC-32)
Dimensions shown in millimeters
ESD 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 this product features
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.
Ordering Guide
ADXRS300 Products
Temperature Package
Package Description
Package Outline
ADXRS300ABG
40C to +85C
32-Lead BGA
BC-32
ADXRS300ABG-Reel
40C to +85C
32-Lead BGA
BC-32
2003 Analog Devices, Inc. All rights reserved. Trademarks and
regis-
tered trademarks are the property of their respective companies.
C03227-0-3/03(A)
Rev. A | Page 8 of 8
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