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Low Noise Angular Rate Sensor
Preliminary Technical Data
FEATURES
Low Noise Density, .013 /s/Hz, over Full Range 300o/sec Dynamic Range Z-axis, yaw rate, response Calibrated Offset and Sensitivity 320 Hz Bandwidth External adjustment with a single component Digital Self-Test High Vibration Rejection High Shock Survivability Embedded Temperature Sensor Output Precision Voltage Reference Output Highly integrated, requiring minimal external components 5V single supply operation -40oC to 85oC
o
ADIS16120
GENERAL DESCRIPTION
The ADIS16120 is a Low Noise and power efficient Angular Rate Sensor (gyroscope). The circuit includes embedded signal conditioning to provide low noise operation over the entire 300o/s dynamic range, as well as excellent offset and gain accuracy over temperature. The surface-micromachining manufacturing technology is the same high volume BIMOS process used by Analog Devices for its high reliability automotive airbag sensor line. The output signal, RATE OUT, is a voltage proportional to angular rate about the axis normal to the top surface of the package. A precision reference and a temperature output are available for system-level use and a digital self-test feature is available to electromechanically excite the sensor and verify proper operation. Variations in Range, Sensitivity, and Bandwidth can be addressed (consult the factory). The fully integrated design eases system implementation, and minimizes overall power consumption to 500mW. The 36mm x 42mm (plus mounting extensions) package provides the convenience of a standard geometry 24-pin interface and four mounting holes.
APPLICATIONS
Guidance and Control Instrumentation Inertial measurement units Stabilization
FUNCTIONAL BLOCK DIAGRAM
Figure 1.
Rev. PrB,
4/20/2006 2:31 AM
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.
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 (c) 2006 Analog Devices, Inc. All rights reserved.
ADIS16120
TABLE OF CONTENTS
Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 4 Rate Sensitive Axis ....................................................................... 4 ESD Caution.................................................................................. 4 Pin Configuration and Function Descriptions............................. 5 Theory of Operation ........................................................................ 6
Preliminary Technical Data
Setting Bandwidth.........................................................................6 Supply and Common Considerations ........................................6 Using the ADIS16120 with a Non-Ratiometric ADC ..............7 Null Adjust .....................................................................................7 Outline Dimensions ..........................................................................7 Ordering Guide .............................................................................7
REVISION HISTORY
11/16/05--PSD1 - Preliminary version 1/5/06 - Pr.A - Preliminary Draft
Rev. PrB | Page 2 of 7
Preliminary Technical Data
SPECIFICATIONS
@TA = 25C, VCC = 5 V, Angular Rate = 0/s, COUT = 0 F, 1 g, unless otherwise noted. Table 1.
Parameter SENSITIVITY Dynamic Range2 Initial Over Temperature3 Nonlinearity NULL Initial Null Over Temperature3 Turn-On Time Linear Acceleration Effect Voltage Sensitivity NOISE PERFORMANCE Rate Noise Density FREQUENCY RESPONSE 3 dB Bandwidth (User Selectable)5 Sensor Resonant Frequency SELF-TEST INPUTS ST RATEOUT Response6 Logic 1 Input Voltage Logic 0 Input Voltage Input Impedance TEMPERATURE SENSOR VOUT at 298K Max Current Load on Pin Scale Factor OUTPUT DRIVE CAPABILITY Output Voltage Swing Capacitive Load Drive 2.5 V REFERENCE Voltage Value Load Drive to Ground Load Regulation Power Supply Rejection Temperature Drift POWER SUPPLY Operating Voltage Range Quiescent Supply Current TEMPERATURE RANGE Specified Performance Grade A Conditions Clockwise rotation is positive output Full-scale range over specifications range @25C VS = 4.75 V to 5.25 V Best fit straight line Min1 300 4.95 TBD
ADIS16120
ADIS16120 Typ Max1
Unit /s mV//s mV//s % of FS V V ms /s/g /s/V /s/Hz Hz kHz
5 5 TBD 2.50 35 TBD 1 0.013 320 14
5.05 TBD
VS = 4.75 V to 5.25 V Power on to 1/2/s of final value, 80Hz bandwidth4 Any axis VCC = 4.75 V to 5.25 V @25C No external capacitance
2.475 2.45
2.525 2.55
ST pin from Logic 0 to 1 Standard high logic level definition Standard low logic level definition To common
+150 3.3
+270
+450 1.7
3.1 2.50
mV V V k V A mV/K V pF V A mV/mA mV/V mV V mA C
Source to common Proportional to absolute temperature IOUT = 100 A 0.25 1000 2.45 Source 0 < IOUT < 200 A 4.75 VS to 5.25 VS Delta from 25C 4.75
50 8.4 VS - 0.25
2.5 200 5.0 1.0 5.0 5.00 100
2.55
5.25 132 +85
Temperature tested to max and min specifications
-40
1 2
All minimum and maximum specifications are guaranteed. Typical specifications are not tested or guaranteed. 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 TMIN or TMAX. 4 Dependent on bandwidth 5 Frequency at which response is 3 dB down from dc response with specified compensation capacitor value. Internal pole forming resistor is 180 k. See the section titled, "SETTING THE BANDWIDTH." 6 Self-test response varies with temperature..
Rev. PrB | Page 3 of 7
ADIS16120
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Acceleration (Any Axis, Unpowered, 0.5 ms) Acceleration (Any Axis, Powered, 0.5 ms) +VS Output Short-Circuit Duration (Any Pin to Common) Operating Temperature Range Storage Temperature Rating 2000 g 2000 g -0.3 V to +6.0 V Indefininte -55C to +125C -65C to +150C
Preliminary Technical Data
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.
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 2000 g and exceed the absolute maximum rating of the device. Care should be exercised in handling to avoid damage.
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.
Rev. PrB | Page 4 of 7
Preliminary Technical Data
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
ADIS16120
Figure 2 - ADIS16120 Pin Assignment (Connector-up View)
Table 3 - Pin Definitions
PIN 1 3 5 7 9 11 13 15 17 19 21 23
NAME ST ST ST ST ST COM VCC VCC COM COM DNC COM Self Test Self Test Self Test Self Test Self Test
DESCRIPTION
PIN 2 4 6 8 10 12 14 16 18 20 22 24
NAME ST ST ST COM TEMPOUT REFOUT COM COM RATEOUT SUMJ DNC DNC Self Test Self Test Self Test
DESCRIPTION
Power supply ground Temperature sensor output Reference voltage Power supply ground Power supply ground Angular rate output signal Summing Junction Do not connect Do not connect
Power supply ground Power Supply Power Supply Power supply ground Power supply ground Do not connect Power supply ground
Rev. PrB | Page 5 of 7
ADIS16120
THEORY OF OPERATION
The base sensor in the ADIS16120 operates on the principle of a resonator gyroscope. Two polysilicon sensing structures each contain a dither frame, which is electrostatically driven to resonance. This produces the necessary velocity element that creates a Coriolis force during angular motion. At the two 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. One advantage of the core dual-sensor design approach is that it provides improved immunity against external g-forces and vibration. The ADIS16120 signal conditioning circuit provides an optimized filtering network that controls the resonator's influence on noise density while supporting a nominal bandwidth of 320Hz. Another feature that helps reduce sensitivity to power supply noise is the integration of approximately 1.8uF of decoupling capacitance inside the ADIS16120's package. The offset and sensitivity performance is factory calibrated across temperature and the internal reference voltage used in this calibration process is offered for external use. A temperature sensor is also provided for system-level use, where appropriate.
Preliminary Technical Data
The bandwidth of the third stage can be reduced by installing a single capacitor across the RATE OUT and SUMJ pins. Figure 4 provides a relationship for selecting the appropriate capacitor value. The initial bandwidth of the ADIS16120 is dominated by the first stage, which is dependent on the sensor's process variation. By reducing the bandwidth of the third filter stage, the influence of the first stage is reduced, providing a method for tighter bandwidth tolerances.
10
3
ADIS16120 Bandwidth vs. Capacitance
10
2
10 Bandwidth (Hz)
1
10
0
10
-1
10
-2
10
-3
10
2
10
3
10
4
10 Capacitance (pF)
5
10
6
10
7
10
8
Figure 4 - Bandwidth vs. Capacitance
SETTING THE BANDWIDTH
An important trade-off in angular rate measurement applications is the one between total system noise and bandwidth. The ADIS16120 offers the flexibility to optimize this trade-off at the system level. The ADIS16120's signal processing circuit provides a three-pole, low pass filter, as described in Figure 3.
SUPPLY AND COMMON CONSIDERATIONS
The ADIS16120 provides approximately 1.8uF of decoupling capacitance internally, eliminating the need for local decoupling capacitors in most systems.
SELF TEST FUNCTION
The ADIS16120 provides a self test function that exercises the sensor's mechanical structure. In order to use this function, pins 1-7 and 9 must be tied together and driven to a "high" logic state.
USING THE ADIS16120 WITH A SUPPLYRATIOMETRIC ADC
The ADIS16120's RATEOUT signal is nonratiometric, i.e., neither 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 ADIS16120 is used with a supply-ratiometric ADC, the ADIS16120's 2.5 V output can be converted and used to make corrections in software for the supply variations.
Figure 3 -Simplified Filtering Network
Rev. PrB | Page 6 of 7
Preliminary Technical Data
OUTLINE DIMENSIONS
ADIS16120
Figure 5. Dimensions shown in millimeters
ORDERING GUIDE
Model ADIS16120AML ADIS16120/PCB Temperature Range -40C to +85C Package Description Evaluation Board Package Outline
(c) 2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR05923-0-4/06(PrB)
Rev. PrB | Page 7 of 7

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