Precision ±1.7 g, ±5 g, ±18 g Single-/ Dual-Axis iMEMS® Accelerometer ADXL103/ADXL203 Data Sheet FEATURES GENERAL DESCRIPTION High performance, single-/dual-axis accelerometer on a single IC chip 5 mm × 5 mm × 2 mm LCC package 1 mg resolution at 60 Hz Low power: 700 μA at VS = 5 V (typical) High zero g bias stability High sensitivity accuracy −40°C to +125°C temperature range X and Y axes aligned to within 0.1° (typical) Bandwidth adjustment with a single capacitor Single-supply operation 3500 g shock survival RoHS compliant Compatible with Sn/Pb- and Pb-free solder processes Qualified for automotive applications The ADXL103/ADXL203 are high precision, low power, complete single- and dual-axis accelerometers with signal conditioned voltage outputs, all on a single, monolithic IC. The ADXL103/ ADXL203 measure acceleration with a full-scale range of ±1.7 g, ±5 g, or ±18 g. The ADXL103/ADXL203 can measure both dynamic acceleration (for example, vibration) and static acceleration (for example, gravity). The typical noise floor is 110 μg/√Hz, allowing signals below 1 mg (0.06° of inclination) to be resolved in tilt sensing applications using narrow bandwidths (<60 Hz). The user selects the bandwidth of the accelerometer using Capacitor CX and Capacitor CY at the XOUT and YOUT pins. Bandwidths of 0.5 Hz to 2.5 kHz can be selected to suit the application. The ADXL103 and ADXL203 are available in a 5 mm × 5 mm × 2 mm, 8-terminal ceramic LCC package. APPLICATIONS Vehicle dynamic controls Electronic chassis controls Platform stabilization/leveling Navigation Alarms and motion detectors High accuracy, 2-axis tilt sensing Vibration monitoring and compensation Abuse event detection FUNCTIONAL BLOCK DIAGRAMS +5V +5V VS VS ADXL203 ADXL103 AC AMP DEMOD OUTPUT AMP CDC SENSOR AC AMP OUTPUT AMP OUTPUT AMP SENSOR RFILT 32kΩ COM DEMOD ST RFILT 32kΩ XOUT COM CX ST RFILT 32kΩ YOUT XOUT CY CX 03757-001 CDC Figure 1. Rev. D 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 ©2004–2011 Analog Devices, Inc. All rights reserved. ADXL103/ADXL203 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Performance................................................................................ 13 Applications....................................................................................... 1 Applications Information .............................................................. 14 General Description ......................................................................... 1 Power Supply Decoupling ......................................................... 14 Functional Block Diagrams............................................................. 1 Setting the Bandwidth Using CX and CY ................................. 14 Specifications..................................................................................... 3 Self Test ........................................................................................ 14 Absolute Maximum Ratings............................................................ 4 Design Trade-Offs for Selecting Filter Characteristics: The Noise/Bandwidth Trade-Off ..................................................... 14 ESD Caution.................................................................................. 4 Pin Configurations and Function Descriptions ........................... 5 Typical Performance Characteristics ............................................. 6 ADXL103 and ADXL203............................................................. 6 AD22293........................................................................................ 9 AD22035 and AD22037 ............................................................ 10 All Models ................................................................................... 12 Using the ADXL103/ADXL203 with Operating Voltages Other than 5 V............................................................................ 15 Using the ADXL203 as a Dual-Axis Tilt Sensor ........................ 15 Outline Dimensions ....................................................................... 16 Ordering Guide .......................................................................... 16 Automotive Products ................................................................. 16 Theory of Operation ...................................................................... 13 REVISION HISTORY 9/11—Rev. C to Rev. D Added AD22293, AD22035, and AD22037 ............... Throughout Changes to Application Section and General Description Section................................................................................................ 1 Changes to Table 1............................................................................ 3 Deleted Figure 13 and Figure 14: Renumbered Sequentially ..... 7 Deleted Figure 17 and Figure 22..................................................... 8 Added Figure 19 to Figure 24; Renumbered Sequentially .......... 9 Added Figure 25 to Figure 34........................................................ 10 Added All Models Section, Figure 35 to Figure 38 .................... 12 Changes to Figure 39...................................................................... 13 Changes to Ordering Guide .......................................................... 16 Changes to Automotive Products Section................................... 16 4/10—Rev. A to Rev. B Changes to Features Section ............................................................1 Updated Outline Dimensions....................................................... 12 Changes to Ordering Guide .......................................................... 12 2/06—Rev. 0 to Rev. A Changes to Features ..........................................................................1 Changes to Table 1.............................................................................3 Changes to Figure 2...........................................................................4 Changes to Figure 3 and Figure 4....................................................5 Changes to the Performance Section..............................................9 4/04—Revision 0: Initial Version 5/10—Rev. B to Rev. C Changes to Figure 24 Caption....................................................... 12 Added Automotive Products Section .......................................... 12 Rev. D | Page 2 of 16 Data Sheet ADXL103/ADXL203 SPECIFICATIONS TA = −40°C to +125°C, VS = 5 V, CX = CY = 0.1 μF, acceleration = 0 g, unless otherwise noted. All minimum and maximum specifications are guaranteed. All typical specifications are not guaranteed. Table 1. Parameter SENSOR Measurement Range 1 Nonlinearity Package Alignment Error Alignment Error (ADXL203) Cross-Axis Sensitivity SENSITIVITY (RATIOMETRIC) 2 Sensitivity at XOUT, YOUT Sensitivity Change Due to Temperature 3 ZERO g BIAS LEVEL (RATIOMETRIC) 0 g Voltage at XOUT, YOUT Initial 0 g Output Deviation From Ideal 0 g Offset vs. Temperature NOISE Output Noise Noise Density FREQUENCY RESPONSE 4 CX, CY Range 5 RFILT Tolerance Sensor Resonant Frequency SELF TEST 6 Logic Input Low Logic Input High ST Input Resistance to GND Output Change at XOUT, YOUT OUTPUT AMPLIFIER Output Swing Low Output Swing High POWER SUPPLY (VDD) Operating Voltage Range Quiescent Supply Current Turn-On Time 7 Test Conditions Each axis ADXL103/ADXL203 Min Typ Max Min ±1.7 ±5 % of full scale X to Y sensor ±0.2 ±1 ±0.1 ±1.5 ±1.25 ±3 AD22293 Typ Max ±6 ±0.2 ±1 ±0.1 ±1.5 AD22035/AD22037 Min Typ Max ±18 ±1.25 ±3 ±0.2 ±1 ±0.1 ±1.5 ±1.25 ±3 Unit g % Degrees Degrees % Each axis VS = 5 V VS = 5 V 960 1000 ±0.3 1040 293 312 ±0.3 331 94 100 ±0.3 106 mV/g % Each axis VS = 5 V VS = 5 V, 25°C 2.4 2.5 ±25 2.6 2.4 2.5 ±50 2.6 2.4 2.5 ±125 2.6 V mg ±0.1 ±0.8 ±0.3 ±1.8 1 110 3 1 200 3 <4 kHz, VS = 5 V 0.002 24 32 5.5 10 40 0.002 24 32 5.5 1 ST 0 to ST 1 No load No load 4 30 450 0.05 50 750 1100 0.2 4.5 4.8 3 0.7 20 1 10 40 50 250 375 0.2 4.5 4.8 3 0.7 20 mg/°C 2 mV rms μg/√Hz rms 10 40 μF kΩ kHz 1 130 0.002 24 32 5.5 1 4 30 125 0.05 6 1.1 ±1 4 30 60 0.05 6 1.1 50 80 100 V V kΩ mV 0.2 4.5 4.8 V V 3 0.7 20 6 1.1 V mA ms Guaranteed by measurement of initial offset and sensitivity. Sensitivity is essentially ratiometric to VS. For VS = 4.75 V to 5.25 V, sensitivity is 186 mV/V/g to 215 mV/V/g. 3 Defined as the output change from ambient-to-maximum temperature or ambient-to-minimum temperature. 4 Actual frequency response controlled by user-supplied external capacitor (CX, CY). 5 Bandwidth = 1/(2 × π × 32 kΩ × C). For CX, CY = 0.002 μF, bandwidth = 2500 Hz. For CX, CY = 10 μF, bandwidth = 0.5 Hz. Minimum/maximum values are not tested. 6 Self-test response changes cubically with VS. 7 Larger values of CX, CY increase turn-on time. Turn-on time is approximately 160 × CX or CY + 4 ms, where CX, CY are in μF. 2 Rev. D | Page 3 of 16 ADXL103/ADXL203 Data Sheet ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Acceleration (Any Axis, Unpowered) Acceleration (Any Axis, Powered) Drop Test (Concrete Surface) VS All Other Pins Rating 3500 g 3500 g 1.2 m −0.3 V to +7.0 V (COM − 0.3 V) to (VS + 0.3 V) Indefinite Output Short-Circuit Duration (Any Pin to Common) Temperature Range (Powered) Temperature Range (Storage) Table 3. Package Characteristics Package Type 8-Terminal Ceramic LCC θJA 120°C/W θJC 20°C/W Device Weight <1.0 gram ESD CAUTION −55°C to +125°C −65°C to +150°C 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. CRITICAL ZONE TL TO TP tP TP TEMPERATURE RAMP-UP TL tL TSMAX TSMIN tS RAMP-DOWN 03757-102 PREHEAT t25°C TO PEAK TIME Figure 2. Recommended Soldering Profile Table 4. Solder Profile Parameters Test Condition Profile Feature Average Ramp Rate (TL to TP) Preheat Minimum Temperature (TSMIN) Maximum Temperature (TSMAX) Time (TSMIN to TSMAX) (tS) TSMAX to TL Ramp-Up Rate Time Maintained above Liquidous (TL) Liquidous Temperature (TL) Time (tL) Peak Temperature (TP) Time Within 5°C of Actual Peak Temperature (tP) Ramp-Down Rate Time 25°C to Peak Temperature Sn63/Pb37 3°C/second maximum Pb-Free 3°C/second maximum 100°C 150°C 60 seconds to 120 seconds 150°C 200°C 60 seconds to 150 seconds 3°C/second 3°C/second 183°C 60 seconds to 150 seconds 240°C + 0°C/−5°C 10 seconds to 30 seconds 6°C/second maximum 6 minutes maximum 217°C 60 seconds to 150 seconds 260°C + 0°C/−5°C 20 seconds to 40 seconds 6°C/second maximum 8 minutes maximum Rev. D | Page 4 of 16 Data Sheet ADXL103/ADXL203 PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS ADXL103 ADXL203 TOP VIEW (Not to Scale) TOP VIEW (Not to Scale) VS VS 8 +X COM 3 4 NC XOUT ST 1 6 NC NC 2 5 NC COM 3 +Y +X 4 NC 7 XOUT 6 YOUT 5 NC 03757-003 NC 2 8 7 03757-002 ST 1 NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. NOTES 1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN. Figure 3. ADXL103 Pin Configuration Figure 4. ADXL203 Pin Configuration Table 5. ADXL103 Pin Function Descriptions Table 6. ADXL203 Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 Pin No. 1 2 3 4 5 6 7 8 Mnemonic ST NC COM NC NC NC XOUT VS Description Self Test Do Not Connect Common Do Not Connect Do Not Connect Do Not Connect X Channel Output 3 V to 6 V Rev. D | Page 5 of 16 Mnemonic ST NC COM NC NC YOUT XOUT VS Description Self Test Do Not Connect Common Do Not Connect Do Not Connect Y Channel Output X Channel Output 3 V to 6 V ADXL103/ADXL203 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS ADXL103 AND ADXL203 VS = 5 V for all graphs, unless otherwise noted. 30 25 10 ZERO g BIAS (V) Figure 8. Y-Axis Zero g Bias Deviation from Ideal at 25°C 30 25 35 35 PERCENT OF POPULATION (%) 40 30 25 20 15 10 0.80 0.70 0.60 0.50 0.40 –0.10 –0.20 –0.30 25 20 15 10 SENSITIVITY (V/g) Figure 10. Y-Axis Sensitivity at 25°C Rev. D | Page 6 of 16 1.06 1.05 03757-015 SENSITIVITY (V/g) Figure 7. X-Axis Sensitivity at 25°C 1.04 1.03 1.02 1.01 1.00 0.99 0.98 0.97 0.96 0.95 0.94 0 1.06 1.05 1.04 1.03 1.02 1.01 1.00 0.99 0.98 0.97 30 5 03757-012 5 0.96 –0.40 Figure 9. Y-Axis Zero g Bias Temperature Coefficient 40 0.95 –0.50 TEMPERATURE COEFFICIENT (mg/°C) Figure 6. X-Axis Zero g Bias Temperature Coefficient 0.94 –0.60 –0.70 –0.80 TEMPERATURE COEFFICIENT (mg/°C) 0.30 03757-014 5 0 0.80 0.70 0.60 0.50 0.40 0.30 0.20 –0.10 –0.20 –0.30 –0.40 –0.60 –0.50 –0.70 –0.80 0 0 03757-011 5 10 0.20 10 15 0 15 20 0.10 PERCENT OF POPULATION (%) 20 0.10 PERCENT OF POPULATION (%) 25 PERCENT OF POPULATION (%) 0.10 ZERO g BIAS (V) Figure 5. X-Axis Zero g Bias Deviation from Ideal at 25°C 0 0 –0.02 –0.04 –0.06 –0.10 –0.08 0 0.08 03757-013 5 0.10 0.08 0.06 0 –0.02 –0.04 –0.06 –0.08 –0.10 0 0.04 03757-010 5 15 0.06 10 20 0.04 15 0.02 PERCENT OF POPULATION (%) 20 0.02 PERCENT OF POPULATION (%) 25 Data Sheet ADXL103/ADXL203 2.60 1.03 2.58 1.02 2.56 SENSITIVITY (V/g) 2.52 2.50 2.48 2.46 2.44 0.99 50 45 45 40 40 35 30 25 20 15 03757-007 10 60 70 80 90 100 110 120 130 X AXIS NOISE DENSITY (mg/√Hz) 140 03757-016 120 110 90 100 80 70 60 50 40 30 20 0 10 –10 –20 35 30 25 20 15 10 03757-008 PERCENT OF POPULATION (%) 50 0 –30 –50 Figure 13. Sensitivity vs. Temperature; Parts Soldered to PCB Figure 11. Zero g Bias vs. Temperature; Parts Soldered to PCB 5 TEMPERATURE (°C) 130 03757-004 0.97 130 120 110 90 TEMPERATURE (°C) 100 80 70 60 50 40 30 20 0 10 –10 –20 –30 –40 2.40 –50 1.00 0.98 2.42 PERCENT OF POPULATION (%) 1.01 –40 VOLTAGE (1V/g) 2.54 5 0 150 60 70 80 90 100 110 120 130 Y AXIS NOISE DENSITY (mg/√Hz) Figure 14. Y-Axis Noise Density at 25°C Figure 12. X-Axis Noise Density at 25°C Rev. D | Page 7 of 16 140 150 Data Sheet 45 40 40 35 35 30 25 20 15 10 25 20 15 10 SELF-TEST OUTPUT (V) 1.00 0.95 0.90 0.85 0.80 0.75 0.70 Figure 17. Y-Axis Self-Test Response at 25°C 0.90 100 90 0.80 0.75 0.70 0.65 0.60 03757-103 60 50 40 30 20 10 CURRENT (µA) Figure 18. Supply Current at 25°C Figure 16. Self-Test Response vs. Temperature Rev. D | Page 8 of 16 1000 900 800 700 600 500 400 200 0 130 120 110 90 100 TEMPERATURE (°C) 80 70 60 50 40 30 20 0 10 –10 –20 –30 –40 0.50 3V 70 300 0.55 5V 80 03757-018 PERCENT OF POPULATION (%) 0.85 –50 0.65 SELF-TEST OUTPUT (V) Figure 15. X-Axis Self-Test Response at 25°C VOLTAGE (1V/g) 0.60 0.50 0.55 0.45 0 0.40 5 1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 0.55 0.50 0.40 0 0.45 5 30 03757-019 PERCENT OF POPULATION (%) 45 03757-017 PERCENT OF POPULATION (%) ADXL103/ADXL203 10 10 0 0 0.387 60 50 40 30 20 Figure 21. X-Axis Sensitivity at 25°C Rev. D | Page 9 of 16 5 Figure 24. Y-Axis Sensitivity at 25°C SENSITIVITY (V/g) 2.55 2.54 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 2.45 2.44 TEMPERATURE COEFFICIENT (mg/°C) 03757-020 03757-119 2.57 10 2.56 15 1.2 Figure 22. Y-Axis Zero g Bias at 25°C 1.0 0.8 0.6 0.4 0.2 ZERO g BIAS (V) 03757-022 70 0.387 80 0.377 80 0.367 90 0.357 Figure 20. X-Axis Zero g Bias Temperature Coefficient 0.347 0 0 5 0.337 10 –0.2 15 0.327 20 –0.4 20 –0.6 25 0.317 Figure 19. X-Axis Zero g Bias at 25°C 0.307 0 –0.8 10 0.297 20 2.43 30 –1.0 40 PERCENT OF POPULATION (%) 50 –1.2 25 PERCENT OF POPULATION (%) 03757-117 2.57 2.56 2.55 2.54 2.53 2.52 2.51 2.50 2.49 2.48 2.47 2.46 2.45 2.44 2.43 PERCENT OF POPULATION (%) 60 0.287 70 PERCENT OF POPULATION (%) TEMPERATURE COEFFICIENT (mg/°C) 03757-118 1.2 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 ZERO g BIAS (V) 03757-021 SENSITIVITY (V/g) 0.377 0.367 0.357 0.347 0.337 0.327 0.317 0.307 0.297 0 –1.2 PERCENT OF POPULATION (%) 0 0.287 PERCENT OF POPULATION (%) Data Sheet ADXL103/ADXL203 AD22293 70 60 50 40 30 20 10 Figure 23. Y-Axis Zero g Bias Temperature Coefficient 60 50 40 30 20 ADXL103/ADXL203 Data Sheet 60 50 50 35 30 30 50 03757-108 40 30 TEMPERATURE COEFFICIENT (mg/°C) 03757-009 3.0 2.5 2.0 1.5 1.0 0.5 –3.0 3.5 03757-106 3.0 2.5 1.5 2.0 1.0 0.5 0 –0.5 –1.0 0 –1.5 0 –2.5 5 –2.0 5 0 10 –0.5 10 15 –1.0 15 20 –1.5 20 25 –2.5 25 –2.0 PERCENT OF POPULATION 35 –3.0 Figure 29. Y-Axis Zero g Bias Temperature Coefficient 25 20 20 PERCENT OF POPULATION 25 15 10 5 15 10 5 Rev. D | Page 10 of 16 103 03757-110 SENSITIVITY (mV/g) Figure 30. Y-Axis Sensitivity at 25°C Figure 27. X-Axis Sensitivity at 25°C 102 101 100 99 97 103 0 03757-107 SENSITIVITY (mV/g) 102 101 100 99 98 97 0 98 PERCENT OF POPULATION Figure 28. Y-Axis Zero g Bias Deviation from Ideal at 25°C Figure 26. X-Axis Zero g Bias Temperature Coefficient PERCENT OF POPULATION 20 ZERO g BIAS (mV) Figure 25. X-Axis Zero g Bias Deviation from Ideal at 25°C TEMPERATURE COEFFICIENT (mg/°C) 10 –50 50 ZERO g BIAS (mV) 03757-105 40 30 20 10 0 –10 0 –20 0 –30 10 –40 10 0 20 –10 20 30 –20 30 40 –30 40 –40 PERCENT OF POPULATION 60 –50 PERCENT OF POPULATION AD22035 AND AD22037 ADXL103/ADXL203 40 45 35 40 15 90 25°C 80 PERCENT OF POPULATION 100.5 100.0 99.5 99.0 98.5 98.0 105°C 70 60 50 40 30 20 10 Rev. D | Page 11 of 16 960 03757-113 CURRENT (µA) Figure 34. Supply Current vs. Temperature Figure 32. Sensitivity vs. Temperature; Parts Soldered to PCB 940 920 900 880 860 840 820 800 780 0 760 125 740 100 720 25 50 75 TEMPERATURE (°C) 700 0 680 –25 03757-112 SENSITIVITY (mV) 0.100 Figure 33. Y-Axis Self Test Response at 25°C 101.0 97.5 –50 0.095 0.060 SELF-TEST OUTPUT (V) Figure 31. X-Axis Self Test Response at 25°C 03757-114 SELF-TEST OUTPUT (V) 03757-111 0.100 0.095 0.090 0.085 0.080 0 0.075 0 0.070 5 0.065 5 0.090 10 0.085 10 20 0.080 15 25 0.075 20 30 0.070 25 35 0.065 PERCENT OF POPULATION 30 0.060 PERCENT OF POPULATION Data Sheet ADXL103/ADXL203 Data Sheet 40 35 35 5.0 4.0 3.0 –5.0 09781-026 PERCENT SENSITIVITY (%) 09781-023 5.0 4.0 3.0 2.0 1.0 –2.0 0 0 –1.0 0 –3.0 5 –4.0 5 2.0 10 1.0 10 15 0 15 20 –1.0 20 25 –2.0 25 30 –3.0 30 –4.0 PERCENT OF POPULATION (%) 40 –5.0 PERCENT OF POPULATION (%) ALL MODELS PERCENT SENSITIVITY (%) Figure 35. Z vs. X Cross-Axis Sensitivity Figure 37. Z vs. Y Cross-Axis Sensitivity 0.9 0.8 VS = 5V VOLTAGE (V) 0.6 0.5 VS = 3V 0.3 –50 0 50 TEMPERATURE (°C) 100 150 Figure 36. Supply Current vs. Temperature 09781-027 0.4 09781-024 CURRENT (mA) 0.7 TIME Figure 38. Turn-On Time; CX, CY = 0.1 μF, Time Scale = 2 ms/DIV Rev. D | Page 12 of 16 Data Sheet ADXL103/ADXL203 THEORY OF OPERATION The ADXL103/ADXL203 are complete acceleration measurement systems on a single, monolithic IC. The ADXL103 is a singleaxis accelerometer, and the ADXL203 is a dual-axis accelerometer. Both parts contain a polysilicon surface-micro-machined sensor and signal conditioning circuitry to implement an open-loop acceleration measurement architecture. The output signals are analog voltages that are proportional to acceleration. The ADXL103/ADXL203 are capable of measuring both positive and negative accelerations from ±1.7 g to at least ±18 g. The accelerometer can measure static acceleration forces, such as gravity, allowing it to be used as a tilt sensor. The sensor is a surface-micromachined polysilicon structure built on top of the silicon wafer. Polysilicon springs suspend the structure over the surface of the wafer and provide a resistance against acceleration forces. Deflection of the structure is measured using a differential capacitor that consists of independent fixed plates and plates attached to the moving mass. The fixed plates are driven by 180° out-of-phase square waves. Acceleration deflects the beam and unbalances the differential capacitor, resulting in an output square wave whose amplitude is proportional to acceleration. Phase-sensitive demodulation techniques are then used to rectify the signal and determine the direction of the acceleration. The output of the demodulator is amplified and brought off-chip through a 32 kΩ resistor. At this point, the user can set the signal bandwidth of the device by adding a capacitor. This filtering improves measurement resolution and helps prevent aliasing. PERFORMANCE Rather than using additional temperature compensation circuitry, innovative design techniques have been used to ensure that high performance is built in. As a result, there is essentially no quantization error or nonmonotonic behavior, and temperature hysteresis is very low (typically less than 10 mg over the −40°C to +125°C temperature range). Figure 11 shows the 0 g output performance of eight parts (x and y axes) over a −40°C to +125°C temperature range. Figure 13 demonstrates the typical sensitivity shift over temperature for VS = 5 V. Sensitivity stability is optimized for VS = 5 V but is still very good over the specified range; it is typically better than ±1% over temperature at VS = 3 V. PIN 8 XOUT = –1g YOUT = 0g TOP VIEW (Not to Scale) PIN 8 XOUT = 0g YOUT = –1g XOUT = 0g YOUT = 0g PIN 8 XOUT = +1g YOUT = 0g EARTH’S SURFACE Figure 39. Output Response vs. Orientation Rev. D | Page 13 of 16 03757-028 PIN 8 XOUT = 0g YOUT = +1g ADXL103/ADXL203 Data Sheet APPLICATIONS INFORMATION POWER SUPPLY DECOUPLING For most applications, a single 0.1 μF capacitor, CDC, adequately decouples the accelerometer from noise on the power supply. However, in some cases, particularly where noise is present at the 140 kHz internal clock frequency (or any harmonic thereof), noise on the supply can cause interference on the ADXL103/ ADXL203 output. If additional decoupling is needed, a 100 Ω (or smaller) resistor or ferrite beads can be inserted in the supply line of the ADXL103/ADXL203. Additionally, a larger bulk bypass capacitor (in the 1 μF to 22 μF range) can be added in parallel to CDC. SETTING THE BANDWIDTH USING CX AND CY The ADXL103/ADXL203 has provisions for band limiting the XOUT and YOUT pins. Capacitors must be added at these pins to implement low-pass filtering for antialiasing and noise reduction. The equation for the 3 dB bandwidth is f–3 dB = 1/(2π(32 kΩ) × C(X, Y)) or more simply, f–3 dB = 5 μF/C(X, Y) The tolerance of the internal resistor (RFILT) can vary typically as much as ±25% of its nominal value (32 kΩ); thus, the bandwidth varies accordingly. A minimum capacitance of 2000 pF for CX and CY is required in all cases. DESIGN TRADE-OFFS FOR SELECTING FILTER CHARACTERISTICS: THE NOISE/BANDWIDTH TRADE-OFF The accelerometer bandwidth selected ultimately determines the measurement resolution (smallest detectable acceleration). Filtering can be used to lower the noise floor, improving the resolution of the accelerometer. Resolution is dependent on the analog filter bandwidth at XOUT and YOUT. The output of the ADXL103/ADXL203 has a typical bandwidth of 2.5 kHz. The user must filter the signal at this point to limit aliasing errors. The analog bandwidth must be no more than half the analog-to-digital sampling frequency to minimize aliasing. The analog bandwidth can be further decreased to reduce noise and improve resolution. The ADXL103/ADXL203 noise has the characteristics of white Gaussian noise, which contributes equally at all frequencies and is described in terms of μg/√Hz (that is, the noise is proportional to the square root of the accelerometer bandwidth). Limit bandwidth to the lowest frequency needed by the application to maximize the resolution and dynamic range of the accelerometer. With the single-pole roll-off characteristic, the typical noise of the ADXL103/ADXL203 is determined by rmsNoise = (110 μg/√Hz) × ( BW × 1.6 ) At 100 Hz, the noise is Table 7. Filter Capacitor Selection, CX and CY Bandwidth (Hz) 1 10 50 100 200 500 rmsNoise = (110 μg/√Hz) × ( 100 × 1.6 ) = 1.4 mg Capacitor (μF) 4.7 0.47 0.10 0.05 0.027 0.01 Often, the peak value of the noise is desired. Peak-to-peak noise can only be estimated by statistical methods. Table 8 is useful for estimating the probabilities of exceeding various peak values, given the rms value. Table 8. Estimation of Peak-to-Peak Noise SELF TEST The ST pin controls the self test feature. When this pin is set to VS, an electrostatic force is exerted on the beam of the accelerometer. The resulting movement of the beam allows the user to test if the accelerometer is functional. The typical change in output is 750 mg (corresponding to 750 mV). This pin can be left opencircuit or connected to common in normal use. Never expose the ST pin to voltages greater than VS + 0.3 V. If the system design is such that this condition cannot be guaranteed (that is, multiple supply voltages are present), a low VF clamping diode between ST and VS is recommended. Peak-to-Peak Value 2 × rms 4 × rms 6 × rms 8 × rms % of Time That Noise Exceeds Nominal Peak-to-Peak Value 32 4.6 0.27 0.006 Peak-to-peak noise values give the best estimate of the uncertainty in a single measurement; peak-to-peak noise is estimated by 6 × rms. Table 9 gives the typical noise output of the ADXL103/ ADXL203 for various CX and CY values. Table 9. Filter Capacitor Selection (CX, CY) Bandwidth (Hz) 10 50 100 500 Rev. D | Page 14 of 16 CX, CY (μF) 0.47 0.1 0.047 0.01 RMS Noise (mg) 0.4 1.0 1.4 3.1 Peak-to-Peak Noise Estimate (mg) 2.6 6 8.4 18.7 Data Sheet ADXL103/ADXL203 USING THE ADXL103/ADXL203 WITH OPERATING VOLTAGES OTHER THAN 5 V The ADXL103/ADXL203 is tested and specified at VS = 5 V; however, it can be powered with VS as low as 3 V or as high as 6 V. Some performance parameters change as the supply voltage is varied. The ADXL103/ADXL203 output is ratiometric, so the output sensitivity (or scale factor) varies proportionally to the supply voltage. At VS = 3 V, the output sensitivity is typically 560 mV/g. The zero g bias output is also ratiometric, so the zero g output is nominally equal to VS/2 at all supply voltages. The output noise is not ratiometric but is absolute in volts; therefore, the noise density decreases as the supply voltage increases. This is because the scale factor (mV/g) increases while the noise voltage remains constant. At VS = 3 V, the noise density is typically 190 μg/√Hz. USING THE ADXL203 AS A DUAL-AXIS TILT SENSOR One of the most popular applications of the ADXL203 is tilt measurement. An accelerometer uses the force of gravity as an input vector to determine the orientation of an object in space. An accelerometer is most sensitive to tilt when its sensitive axis is perpendicular to the force of gravity, that is, parallel to the earth’s surface. At this orientation, its sensitivity to changes in tilt is highest. When the accelerometer is oriented on axis to gravity, that is, near its +1 g or –1 g reading, the change in output acceleration per degree of tilt is negligible. When the accelerometer is perpendicular to gravity, its output changes nearly 17.5 mg per degree of tilt. At 45°, its output changes at only 12.2 mg per degree, and resolution declines. Dual-Axis Tilt Sensor: Converting Acceleration to Tilt Self test response in g is roughly proportional to the square of the supply voltage. However, when ratiometricity of sensitivity is factored in with supply voltage, self test response in volts is roughly proportional to the cube of the supply voltage. So at VS = 3 V, the self test response is approximately equivalent to 150 mV or equivalent to 270 mg (typical). The supply current decreases as the supply voltage decreases. Typical current consumption at VDD = 3 V is 450 μA. When the accelerometer is oriented so both its x-axis and y-axis are parallel to the earth’s surface, it can be used as a 2-axis tilt sensor with a roll axis and a pitch axis. Once the output signal from the accelerometer has been converted to an acceleration that varies between –1 g and +1 g, the output tilt in degrees is calculated as PITCH = ASIN(AX/1 g) ROLL = ASIN(AY/1 g) Be sure to account for overranges. It is possible for the accelerometers to output a signal greater than ±1 g due to vibration, shock, or other accelerations. Rev. D | Page 15 of 16 ADXL103/ADXL203 Data Sheet OUTLINE DIMENSIONS 0.087 0.078 0.069 0.020 0.015 0.010 (R 4 PLCS) 0.028 0.020 DIA 0.012 1 7 0.180 0.177 SQ 0.174 0.106 0.100 0.094 0.075 REF R 0.008 (8 PLCS) 0.008 0.006 0.004 TOP VIEW R 0.008 (4 PLCS) 0.054 0.050 0.046 (PLATING OPTION 1, SEE DETAIL A FOR OPTION 2) 5 3 BOTTOM VIEW 0.077 0.070 0.063 0.019 SQ DETAIL A (OPTION 2) 05-21-2010-D 0.203 0.197 SQ 0.193 0.030 0.025 0.020 Figure 40. 8-Terminal Ceramic Leadless Chip Carrier [LCC] (E-8-1) Dimensions shown in inches ORDERING GUIDE Model 1, 2 ADXL103CE ADXL103CE–REEL ADXL103WCEZB-REEL AD22035Z AD22035Z-RL AD22035Z-RL7 ADW22035Z ADW22035Z-RL ADW22035Z-RL7 ADXL203CE ADXL203CE-REEL ADXL203WCEZB-REEL ADXL203EB AD22293ZA ADW22293ZA AD22037Z AD22037Z-RL AD22037Z-RL7 ADW22037Z ADW22037Z-RL ADW22037Z-RL7 1 2 Axes 1 1 1 1 1 1 1 1 1 2 2 2 Device Generic ADXL103 ADXL103 ADXL103 ADXL103 ADXL103 ADXL103 ADXL103 ADXL103 ADXL103 ADXL203 ADXL203 ADXL203 g-Range ±1.7 ±1.7 ±1.7 ±18 ±18 ±18 ±18 ±18 ±18 ±1.7 ±1.7 ±1.7 Specified Voltage (V) 5 5 5 5 5 5 5 5 5 5 5 5 Temperature Range −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C –40°C to +125°C −40°C to +125°C −40°C to +125°C 2 2 2 2 2 2 2 2 ADXL203 ADXL203 ADXL203 ADXL203 ADXL203 ADXL203 ADXL203 ADXL203 ±5 ±5 ±18 ±18 ±18 ±18 ±18 ±18 5 5 5 5 5 5 5 5 −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C −40°C to +125°C Package Description 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC Evaluation Board 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC 8-Terminal Ceramic LCC Package Option E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 E-8-1 Z = RoHS Compliant Part. W = Qualified for Automotive Applications. AUTOMOTIVE PRODUCTS The ADXL103W, ADW22035, ADXL203W, ADW22293, and ADW22037 models are available with controlled manufacturing to support the quality and reliability requirements of automotive applications. Note that these automotive models may have specifications that differ from the commercial models; therefore, designers should review the Specifications section of this data sheet carefully. Only the automotive grade products shown are available for use in automotive applications. Contact your local Analog Devices account representative for specific product ordering information and to obtain the specific Automotive Reliability reports for these models. ©2004–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D03757-0-9/11(D) Rev. D | Page 16 of 16