Low Noise, Angular Rate Sensor ADIS16120 FEATURES GENERAL DESCRIPTION Low noise density, 0.015o/sec/√Hz 300o/sec dynamic range Z-axis, yaw rate response Calibrated offset and sensitivity 320 Hz bandwidth, adjustable 35 ms turn-on time Digital self-test High vibration rejection High shock survivability Embedded temperature sensor output Precision voltage reference output 5 V single-supply operation −40°C to +85°C The ADIS16120 is a low noise, angular rate sensor (gyroscope) that includes all of the necessary embedded signal conditioning to provide a low noise, analog output over the complete dynamic range of ±300o/sec. Factory calibration provides excellent offset and gain accuracy. The unique design implementation provides superior stability over variations in temperature, voltage, linear acceleration, vibration, and next level assembly. The surfacemicromachining manufacturing technology is the same high volume BiMOS process used by Analog Devices, Inc. for its high reliability automotive sensor products. The output signal, RATEOUT, is a voltage proportional to the angular rate about the axis normal to the top surface of the package. A precision reference and a temperature output are provided for system level calibrations and a digital self-test feature is provided to enable system-level diagnostics. The selftest function electromechanically excites the sensor to verify proper operation. APPLICATIONS Guidance and control Instrumentation Inertial measurement units (IMU) Stabilization The 35.6 mm × 42.4 mm (plus mounting extensions) package provides the convenience of a standard geometry 24-pin interface and four mounting holes for simple installation. Consult the factory for additional dynamic range and sensitivity options. FUNCTIONAL BLOCK DIAGRAM TEMPOUT REFOUT ADIS16120 TEMPERATURE SENSOR FILTER MEMS ANGULAR RATE SENSOR SIGNAL CONDITIONING SENSITIVITY AND OFFSET CALIBRATION RATEOUT COM SELF-TEST 05923-001 ST 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 owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved. ADIS16120 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Performance Characteristics ..............................................6 Applications....................................................................................... 1 Theory of Operation .........................................................................8 General Description ......................................................................... 1 Setting the Bandwidth ..................................................................8 Functional Block Diagram .............................................................. 1 Self-Test Function .........................................................................8 Specifications..................................................................................... 3 Applications........................................................................................9 Absolute Maximum Ratings............................................................ 4 Achieving Optimal Noise Performance .....................................9 Thermal Resistance ...................................................................... 4 Using the ADIS16120 with a Supply-Ratiometric ADC..........9 Rate Sensitive Axis ....................................................................... 4 Second Level Assembly ................................................................9 ESD Caution.................................................................................. 4 Outline Dimensions ....................................................................... 11 Pin Configuration and Function Descriptions............................. 5 Ordering Guide .......................................................................... 11 REVISION HISTORY 11/06—Rev. 0 to Rev. A Changes to Specifications Section.................................................. 3 Added Figure 13................................................................................ 8 7/06—Revision 0: Initial Version Rev. A | Page 2 of 12 ADIS16120 SPECIFICATIONS @ TA = 25°C, VCC = 5 V, angular rate = 0°/sec, COUT = 0 μF, ±1 g, unless otherwise noted. Table 1. Parameter SENSITIVITY Dynamic Range2 Initial Over Temperature3 Nonlinearity NULL Initial Null Over Temperature In Run Bias Stability Angle Random Walk Turn-On Time Linear Acceleration Effect Voltage Sensitivity NOISE PERFORMANCE Rate Noise Density4 FREQUENCY RESPONSE 3 dB Bandwidth5 Sensor Resonant Frequency SELF-TEST INPUTS ST RATEOUT Response6 Logic 1 Input Voltage Logic 0 Input Voltage Input Impedance TEMPERATURE SENSOR VOUT at 298 K Max Current Load on Pin Scale Factor OUTPUT DRIVE CAPABILITY Output Voltage Swing Capacitive Load Drive7 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 specified operating conditions @ 25°C Min1 ±300 4.95 4.75 Best fit straight line VS = 4.75 V to 5.25 V 1σ, @ 25°C 1σ, @ 25°C Power on to ±0.5°/sec of final value, 80 Hz bandwidth Any axis VCC = 4.75 V to 5.25 V 2.49 2.4 Typ Max1 Unit 5 5 0.04 5.05 5.25 degrees/sec mV/degrees/sec mV/degrees/sec % of FS 2.50 2.51 2.6 V V degrees/sec degrees/sec/√Hz ms degrees/sec/g degrees/sec/V 0.020 degrees/sec/√Hz 0.005 0.9 35 0.05 0.4 @ 25°C 0.015 No external capacitance 320 14 ST pin from Logic 0 to Logic 1 Standard high logic level definition Standard low logic level definition To common 175 3.3 270 Hz kHz 365 1.7 3.13 2.50 Source to common Proportional to absolute temperature IOUT = ±1 mA 50 8.4 0.25 1000 VS − 0.25 V pF 2.5 150 5 1 5 2.55 V μA mV/mA mV/V mV 4.75 5.00 95 5.25 110 V mA +85 °C IOUT = 0 mA, +5 V, 25°C 1 V μA mV/K 2.45 Source 0 μA< IOUT < 200 μA 4.75 VS to 5.25 VS Delta from 25°C Temperature tested to max and min specifications mV V V kΩ –40 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 4.75 V to 5.25 V supplies. 3 Specification refers to the maximum extent of this parameter as a worst-case value of TMIN or TMAX, along with long-term effects. 4 Resulting bias stability is <0.01°/sec. 5 Frequency at which response is 3 dB from dc response. See the Setting the Bandwidth section for adjusting this value. 6 Self-test response varies with temperature. 7 The value offered herein assures stability in the output buffer amplifier stage and no degradation of other specified performance parameters. 2 Rev. A | Page 3 of 12 ADIS16120 ABSOLUTE MAXIMUM RATINGS RATE SENSITIVE AXIS 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 Range Rating 2000 g 2000 g −0.3 V to +6.0 V Indefinite −55°C to +125°C −65°C to +150°C This is a z-axis rate sensing device that is also called a yaw rate sensing device. It produces a positive-going change in the output voltage as a result of clockwise rotation about the axis, normal to the package top; that is, clockwise when looking down at the package lid. 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. RATE AXIS RATEOUT VCC = 5V INAL ITUD LONGAXIS The ADIS16120 provides a temperature output that is representative of the junction temperature. This can be used for system-level monitoring and power management/thermal characterization. LATER AL AX IS θJA 15.7°C/W θJC 1.48°C/W GND Figure 2. Rotational Measurement Orientation ESD CAUTION Table 3. Thermal Characteristics Package Type 24-Pin Module 2.5V RATE OF ROTATION 0.25V 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. THERMAL RESISTANCE 4.75V + Weight 28.5 grams typical Rev. A | Page 4 of 12 05923-002 Table 2. ADIS16120 2 4 1 3 6 8 10 12 14 16 18 20 22 24 5 7 9 11 13 15 17 19 21 23 05923-003 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 3. Pin Configuration (Connector-Up View) Table 4. Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Mnemonic ST ST ST ST ST ST ST COM ST TEMPOUT DNC REFOUT VCC COM VCC COM COM RATEOUT COM FILTER DNC DNC COM DNC Description Self-Test. Self-Test. Self-Test. Self-Test. Self-Test. Self-Test. Self-Test. Power Supply Ground. Self-Test. Temperature Sensor Output. Do Not Connect. Reference Voltage. Power Supply. Power Supply Ground. Power Supply. Power Supply Ground. Power Supply Ground. Angular Rate Output Signal. Power Supply Ground. Filter Input. This is used in conjunction with RATEOUT; see the Setting the Bandwidth section for use. Do Not Connect. Do Not Connect. Power Supply Ground. Do Not Connect. Rev. A | Page 5 of 12 ADIS16120 TYPICAL PERFORMANCE CHARACTERISTICS 5.1 2.53 VCC = 5.25V 2.52 4.9 2.51 4.8 NULL (V) SENSITIVITY (mV/°/s) 5.0 VCC = 5.0V 4.7 2.50 2.49 4.6 2.48 4.5 VCC = 4.75V 100 200 300 400 500 600 RATE (°/s) 2.47 –40 25 55 85 TEMPERATURE (°C) Figure 4. Gain Sensitivity vs. Angular Rate and Power Supply 5.05 –20 05923-007 0 05923-004 4.4 Figure 7. Null vs. Temperature, VCC = 5 V 0.31 +25°C 5.00 0.29 –40°C 4.90 SELF-TEST (ΔV) SENSITIVITY (mV/°/s) 4.95 +85°C 4.85 4.80 4.75 0.27 0.25 0.23 4.70 0.21 4.65 100 200 300 400 500 600 RATE (°/s) 0.19 –40 –20 25 55 05923-008 0 05923-005 4.60 85 TEMPERATURE (°C) Figure 5. Gain Sensitivity vs. Angular Rate and Temperature, VCC = 5 V Figure 8. Self-Test vs. Temperature, VCC = 5 V 5.05 104 102 100 CURRENT (mA) VCC = 5V 4.95 4.90 VCC = 5.25V 98 96 VCC = 5.0V 94 92 VCC = 4.75V 90 4.85 4.80 –40 –20 25 55 85 TEMPERATURE (°C) Figure 6. Gain Sensitivity vs. Temperature @ 300°/sec 86 –50 0 50 100 TEMPERATURE (°C) Figure 9. Power Supply Current vs. Temperature and Power Supply Rev. A | Page 6 of 12 05923-009 88 05923-006 SENSITIVITY (mV/°/s) 5.00 ADIS16120 –60 0.025 fS = 34596Hz VCC = 5V 16384 SAMPLES 0.023 –70 0.019 MAGNITUDE (dBV) NOISE DENSITY (°/s/ Hz) 0.021 0.017 0.015 0.013 –80 –90 –100 0.011 –110 0.009 85 –120 TEMPERATURE (°C) 1 1k 10k 100k 100 Figure 12. Noise Density vs. Frequency MEAN = 0.0147°/s/ Hz STANDARD DEVIATION = 0.0010 0.1 ROOT ALLAN VARIANCE (°/s) 20 15 10 05923-011 0.0175 0.0171 0.0167 0.0163 0.0159 0.0155 0.0151 0.0147 0.0143 0.0135 0.0131 0.0127 0.0123 0 0.0119 5 0.0115 PERCENTAGE OF POPULATION 100 FREQUENCY (Hz) Figure 10. Noise Density vs. Temperature, VCC = 5 V 25 10 05923-013 25 05923-014 –40 05923-010 0.007 BIN (°/s/ Hz) 0.01 0.001 0.1 1 10 TAU (Seconds) Figure 13. Root Allan Variance vs. Integration Time Figure 11. Noise Histogram Rev. A | Page 7 of 12 ADIS16120 THEORY OF OPERATION The offset and sensitivity performance is factory calibrated 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. 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 signal processing circuit of the ADIS16120 provides a three-pole, low-pass filter, as shown in Figure 14. FILTER 820pF 180kΩ LPF F1 = 400Hz ±35% F2 = 1kHz ±10% 180kΩ OUTPUT BUFFER RATEOUT F3 = 1kHz ±10% 05923-015 LPF Figure 14. Simplified Filtering Network The bandwidth of the third stage can be reduced by installing a single capacitor across the RATEOUT and FILTER pins. Figure 15 provides a relationship for selecting the appropriate capacitor value and Table 5 provides bandwidth estimates for standard capacitor values. 1000 100 10 1 0.1 0.01 0.001 100 1k 10k 100k 1M 10M 100M CAPACITANCE (pF) 05923-016 The ADIS16120 signal conditioning circuit provides an optimized filtering network that controls the resonators influence on noise while supporting a nominal bandwidth of 320 Hz. Another feature that helps reduce sensitivity to power supply noise is the integration of approximately 1.8 μF of decoupling capacitance inside the ADIS16120. The initial bandwidth of the ADIS16120 is dominated by the first stage and is dependent on the process variation of the base sensor. By reducing the bandwidth of the third filter stage, the influence of the first stage is reduced, and tighter bandwidth tolerances can be achieved. BANDWIDTH (Hz) The base sensor in the ADIS16120 operates on the principle of a resonator gyroscope. Two polysilicon sensing structures each contain a dither frame that 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 fingers to form a capacitive pickoff structure that senses Coriolis acceleration. The resulting signal is fed to a series of gain and demodulation stages that produce the representative rate signal output. One advantage of the core dual-sensor design approach is that it provides improved rejection of external g-forces and vibration. Figure 15. Bandwidth vs. Capacitance Table 5. Nominal Bandwidth for Standard Capacitor Values C (pF) BW (Hz) C (pF) BW (Hz) 1000 1200 1500 1800 2200 2700 3300 3900 4300 4700 5100 5600 6200 7500 8200 9100 267.3 256.2 244.1 225.5 211.9 192.3 173.2 156.4 148.9 140.4 132.9 124.5 115.6 99.0 92.7 85.5 10,000 12,000 15,000 18,000 22,000 27,000 33,000 39,000 43,000 47,000 51,000 56,000 62,000 75,000 82,000 91,000 78.4 67.1 55.2 46.4 38.8 31.8 26.2 22.2 20.2 18.5 17.1 15.6 14.1 11.7 10.7 9.6 SELF-TEST FUNCTION The ADIS16120 provides a self-test function that exercises the mechanical structure of the sensor. To use this function, Pin 1 to Pin 7 and Pin 9 must be tied together and driven to a high logic state to activate this function. A continuous self-test does not damage the device. Rev. A | Page 8 of 12 ADIS16120 APPLICATIONS ACHIEVING OPTIMAL NOISE PERFORMANCE SECOND LEVEL ASSEMBLY There are several system level considerations that can have an impact on the noise and accuracy of the ADIS16120. Understanding and managing these factors can influence the behavior of any high performance system. The ADIS16120 is designed to be mounted with the header pins either facing up (bulkhead mount) or facing down (printed circuit board mount). In either case, the mating socket should be a Samtec P/N CLM-112-02-L-D-A or equivalent. This family of connectors offers multiple configurations for use in mating to the ADIS16120. Consult the manufacturers reference material if this connector does not match system level requirements. The recommended pad/hole layout for this socket can be found in Figure 16. Use the alignment pins identified in this figure, along with either Figure 17 or Figure 18, to design an appropriate interface for the ADIS16120. Note that in order to meet worst-case dimensional tolerances of the entire package, the header pins extend beyond the height of the package, requiring the mating printed circuit board (PCB) to have holes to prevent bottoming-out of the ADIS16120s pins. Without the holes, a bottom-out event would place the ADIS16120 under stress, which can affect accuracy performance. Also, in either mounting configuration, make sure that the ADIS16120 is firmly mounted to prevent additional mechanical vibration. Supply and Common Considerations The ADIS16120 provides approximately 1.8 μF of decoupling capacitance. This capacitance is distributed throughout the device and should be taken into account when considering potential noise threats on the power supply lines. Reference Output The same reference that is used to calibrate the offset performance of the ADIS16120 is made available for system level use. This pin has 1 μF of capacitance, providing a degree of noise filtering. However, careful use of this pin is necessary considering that any noise or level-shifting influences introduce errors in the output. Bandwidth Setting 0.4334 [11.0] If COUT is applied to reduce the bandwidth of the ADIS16120’s response, it should be placed close to the device. Long cable leads and PCB traces can increase the risk of noise introduction. USING THE ADIS16120 WITH A SUPPLYRATIOMETRIC ADC 0.019685 [0.5000] (TYP) 0.0240 [0.610] 0.054 [1.37] The RATEOUT signal of the ADIS16120 is nonratiometric, that is, neither the null voltage nor the rate sensitivity is proportional to the supply. Instead, 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 2.5 V output of the ADIS16120 can be converted and used to make corrections in software for the supply variations. 0.022± DIA (TYP) NON PLATED 0.022 DIA THRU HOLE (TYP) THRU HOLE 2× NON PLATED THRU HOLE Rev. A | Page 9 of 12 0.0394 [1.00] Figure 16. Mating Socket Recommended Pad Layout Dimensions are shown in inches (millimeters) 05923-017 0.0394 [1.00] 0.1800 [4.57] ADIS16120 Bulkhead Mounting Printed Circuit Board Mounting Figure 17 provides the hole locations and maximum size for the bulkhead mount option. When using the bulkhead mount option, the user can interface to the ADIS16120 header via a cable or an interface board/cable assembly. This assembly is not provided. Consult www.analog.com/isensor for the latest interface/evaluation board options. Figure 19 shows the PCB mount hole locations for correct alignment. Hole locations for optional alignment posts are shown in this diagram. Hole locations are provided in Figure 18 for the interface board. Hole locations for optional alignment posts are also shown in Figure 18. The hole shown in the interface board for the mounting screw clearance is sized to provide alignment flexibility. A washer is required under the screw head for these hole sizes. 37.680 BSC 25 BSC 2.400 BSC 2× 0.736 BSC 2× 10 BSC 4 BSC 2× Ø2 BSC 2× HOLES FOR ALIGNMENT POSTS AS REQUIRED 37.680 BSC 7.500 BSC Ø0.560 BSC 2× HOLES TO PROVIDE ACCURATE ALIGNMENT 37.600 BSC 2× OF SOCKET (SEE SOCKET PCB LAYOUT DRAWING). 3.240 BSC 2× 37 BSC 2× 3.100 BSC 2.400 BSC 2× 31.200 BSC R1.200 BSC 8× Figure 19. Printed Circuit Board Mounting Hole Pattern 31.200 BSC DRILL AND TAP 4× MAX 2-56 05923-018 3.240 BSC 2× Figure 17. Bulkhead Mount Attachment Hole Locations 37.680 BSC 10 BSC Ø2 BSC 2× HOLES FOR ALIGNMENT POSTS AS REQUIRED. 0.736 BSC 2× 7.500 BSC 2× Ø3 BSC 2× 0.600 BSC 2× 6.340 BSC 2× Ø0.560 BSC 2× HOLES TO PROVIDE ACCURATE ALIGNMENT OF SOCKET (SEE SOCKET PCB LAYOUT DRAWING). 05923-019 25 BSC Figure 18. Interface Board Hole Locations for Bulkhead Mount Rev. A | Page 10 of 12 05923-020 37 BSC 2× 4 BSC 2× ADIS16120 OUTLINE DIMENSIONS 42.154 41.900 41.646 37.830 37.680 37.530 32.550 32.350 32.150 2.40 BSC DETAIL A 25.00 BSC 4.00 BSC 42.654 42.400 42.146 TOP VIEW 37.140 36.990 36.840 3.24 BSC (2 PLACES) 31.350 31.200 31.050 14.054 13.800 13.546 2.20 BSC (2 PLACES) 35.854 35.600 35.346 2.00 BSC DIAMETER 1.00 BSC (LEAD PITCH) END VIEW DETAIL A 101906-B 0.30 SQ BSC 1.00 BSC (LEAD PITCH) 3.04 2.84 2.64 Figure 20. ADIS16120 PCB Module with Connector Interface (ML-24) Dimensions shown in millimeters ORDERING GUIDE Model ADIS16120AML ADIS16120/PCB Temperature Range −40°C to +85°C Package Description PCB Module with Connector Interface Evaluation Board Rev. A | Page 11 of 12 Package Option ML-24 ADIS16120 NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05923-0-11/06(A) Rev. A | Page 12 of 12