Preliminary Technical Data High Performance Wide Bandwidth Accelerometer ADXL001 FEATURES FUNCTIONAL BLOCK DIAGRAM High Performance Accelerometer ±70g, ±250g And ±500g Wideband Ranges Available 22kHz Resonant Frequency Structure High Linearity (0.2% of Full-scale) Low-Noise (4 mg/ Hz ) Sensitive Axis in the Plane of the Chip Frequency Response Down To DC Full Differential Signal Processing High Resistance to EMI/RFI Complete Electromechanical Self-test Output Ratiometric to Supply Velocity Preservation During Acceleration Input Overload Low-Power Consumption (2.5mA typ) 5mm LCC Hermetic Ceramic Package MOD SELF–TEST Figure 1. Functional Block Diagram APPLICATIONS Vibration Monitoring Shock Detection Sports Diagnostic Equipment Medical Instrumentation Industrial Monitoring GENERAL DESCRIPTION The ADXL001 is a major advance over previous generations of accelerometers - providing high performance and wide bandwidth. This part is ideal for industrial, medical, and military applications where wide bandwidth, small size, low power, and robust performance are essential. The ADXL001 is available in industry standard 8 pin LCC and is rated to work over the extended industrial temperature range (-40 to +125C). 40.0 35.0 30.0 25.0 Response (dB) Utilizing our proprietary 5th Generation iMEMs process enables the ADXL001 to provide the desired dynamic range that extends from +/-70g to +/-500g in combination with 22kHz of bandwidth. The accelerometer output channel passes through a wide bandwidth differential to single ended converter, which allows access to the full mechanical performance of the sensor. 20.0 15.0 10.0 5.0 0.0 The part can operate on voltage supplies from 3.3V to 5V. -5.0 -10.0 The ADXL001 also has a Self-Test (ST) pin that can be asserted to verify the full electromechanical signal chain for the accelerometer channel. 1 10 100 1000 10000 100000 Frequency (Hz) Figure 2. Sensor Frequency Response This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA 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 ©2008 Analog Devices, Inc. All rights reserved. ADXL001 Preliminary Technical Data TABLE OF CONTENTS Features .............................................................................................. 1 Applications........................................................................................8 Applications....................................................................................... 1 Application Circuit........................................................................8 GENERAL DESCRIPTION ............................................................ 1 Self-Test ..........................................................................................8 Functional Block Diagram .............................................................. 1 Acceleration Sensitive Axis ..........................................................8 Revision History ............................................................................... 2 Operating Voltages Other Than 5V............................................8 Specifications..................................................................................... 3 Layout, Grounding, and Bypassing Considerations .....................9 Absolute Maximum Ratings............................................................ 5 Clock Frequency Supply Response .............................................9 ESD Caution.................................................................................. 5 Power Supply Decoupling ............................................................9 Pin Configuration and Function Descriptions............................. 6 Electromagnetic Interference ......................................................9 Theory of Operation ........................................................................ 7 Outline Dimensions ....................................................................... 10 Design Principles.......................................................................... 7 Ordering Guide............................................................................... 10 Mechanical Sensor........................................................................ 7 REVISION HISTORY 4/08— Preliminary Technical Data Rev A This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 2 of 10 Preliminary Technical Data ADXL001 SPECIFICATIONS Table 1. ADXL001 Specifications ( @ TA = -40°C to +125°C, VS = 3.3V ± 5% DC, Acceleration = 0g; unless otherwise noted) 70g Conditions Min 250g Typ Max 0.2 2 Min 500g Typ Max 0.2 2 Min Typ Max 0.2 2 Units SENSOR Nonlinearity Alignment error 1 130 130 130 kHz Includes pkg. Alignment 2% 2% 2% % 22 22 22 kHz Package resonance Cross-axis sensitivity Resonant frequency Quality factor SENSITIVITY 1 2.5 Ratiometric(1) 2.5 1 70 2.5 1 -250 degree 250 1 -500 500 % Full scale range Iout<=+/-100µA Sensitivity Vs=3.3V, 100Hz 16.0 4.30 2.15 mV/g Sensitivity Vs=5V, 100Hz 24.2 6.5 3.26 mV/g OFFSET -70 1 % Die in package g Ratiometric(1) Zero-g output Vs=3.3V 1.35 Zero-g output Vout-Vs/2 -90.9 1.65 1.95 TBD 1.65 TBD TBD 1.65 TBD 90.9 V mV/V Noise Noise 10Hz-400Hz 100 100 100 mg rms Noise density 10Hz-400Hz 4 4 4 mg/rt Hz Frequency Response -3dB frequency 22 22 22 kHz -3dB frequency drift 2 2 2 % 400 TBD TBD mV TBD mV/V^3 Self Test Delta V Vs=3.3V Delta V (cubic vs. Vs) 10 Logic input high Vs=3.3V Logic input low Vs=3.3V Input resistance To Ground 30 Iout=+/-100µA 0.2 TBD 2.1 2.1 2.1 0.66 50 V 0.66 30 50 0.66 30 50 V kΩ Output Amplifier Output swing Capacitive load PSRR/CFSR Vs-0.2 1000 DC-1MHz 0.2 Vs-0.2 1000 0.5 0.2 Vs-0.2 1000 0.5 V pF 0.5 V/V Power Supply (Vs) Functional Range 3.135 6 Isupply 2.5 Turn-on time TBD 3.135 5 6 2.5 3.135 5 TBD This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 3 of 10 6 2.5 TBD 5 V mA ms ADXL001 Preliminary Technical Data CRITICAL ZONE TL TO TP tP TP tL TSMAX TSMIN tS PREHEAT RAMP-DOWN 06896-022 TEMPERATURE (T) RAMP-UP TL tPEAK TIME (t) Figure 3. Recommended Soldering Profile Table 2. Recommended Soldering Profile 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 (tPEAK) Sn63/Pb37 3°C/s maximum Pb-Free 3°C/s maximum 100°C 150°C 60 sec to 120 sec 150°C 200°C 60 sec to 150 sec 3°C/s 3°C/s 183°C 60 sec to 150 sec 240°C + 0°C/−5°C 10 sec to 30 sec 6°C/s maximum 6 minute maximum 217°C 60 sec to 150 sec 260°C + 0°C/−5°C 20 sec to 40 sec 6°C/s maximum 8 minute maximum This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 4 of 10 Preliminary Technical Data ADXL001 ABSOLUTE MAXIMUM RATINGS Table 3. Absolute Maximum Ratings Parameter* Acceleration (Any Axis, Unpowered and Powered) Supply Voltage Vs Output Short Circuit Duration (Vout, to Ground) Storage Temperature Soldering Temperature Range (Soldering 10 sec) Operating Temperature Range ESD CAUTION Rating 4000 g -0.3 to 7.0V Indefinite -65°C to 150°C 245°C -55°C to 125°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. Drops onto hard surfaces can cause shocks of greater than 4000 g and can exceed the absolute maximum rating of the device. Exercise care during handling to avoid damage. This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 5 of 10 ADXL001 Preliminary Technical Data PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 4. Pin Configuration Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 DNC Do Not Connect 2 DNC Do Not Connect 3 COM Common 4 ST Self Test Control (Logic Input) 5 DNC Do Not Connect 6 XOUT X Axis Acceleration Output 7 VDD 3.135 V to 6 V (Should Be Connected Physically To VDD2) 8 VDD2 3.135 V to 6 V (Should Be Connected Physically To VDD) This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 6 of 10 Preliminary Technical Data ADXL001 THEORY OF OPERATION DESIGN PRINCIPLES MECHANICAL SENSOR The ADXL001 accelerometer provides a fully differential sensor structure and circuit path for excellent resistance to EMI/RFI interference. The ADXL001 is built using the Analog Devices, Inc., SOIMEMS sensor process. The sensor device is micromachined in-plane in the SOI device layer. Trench isolation is used to electrically isolate, but mechanically couple, the differential sensing elements. Single-crystal silicon springs suspend the structure over the handle wafer and provide resistance against acceleration forces. MOVABLE FRAME PLATE CAPACITORS UNIT SENSING CELL FIXED PLATES UNIT FORCING CELL MOVING PLATE ANCHOR Figure 5. Simplified View of Sensor Under Acceleration This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 7 of 10 06896-019 Figure 5 is a simplified view of one of the differential sensor cell blocks. Each sensor block includes several differential capacitor unit cells. Each cell is composed of fixed plates attached to the device layer and movable plates attached to the sensor frame. Displacement of the sensor frame changes the differential capacitance. On-chip circuitry measures the capacitive change. ANCHOR ACCELERATION This latest generation SOIMEMS device takes advantage of mechanically coupled but electrically isolated differential sensing cells. This improves sensor performance and size as a single proof mass generates the fully differential signal. The sensor signal conditioning also uses electrical feedback with zero-force feedback for improved accuracy and stability. This force-feedback cancels out the electrostatic forces contributed by the sensor circuitry. ADXL001 Preliminary Technical Data APPLICATIONS APPLICATION CIRCUIT ACCELERATION SENSITIVE AXIS Figure 6 shows the standard application circuit for the ADXL001. Note that VDD and VDD2 should always be connected. The output is shown connected to a 1000 pF output capacitor for improved EMI performance and can be connected directly to the ADC input of a microcontroller. See the ADC specifications for proper antialiasing filtering, based on the user’s sample rate. The ADXL001 is an X-Axis acceleration and vibration-sensing device. It produces a positive-going output voltage for vibration toward its Pin 8 marking. 06896-002 PIN 8 Figure 7. XOUT Increases with Acceleration in the +X-Axis Direction OPERATING VOLTAGES OTHER THAN 5V The ADXL001 is specified at VS = 3.3 V and VS = 5 V. Note that some performance parameters change as the voltage is varied. In particular, the Xout output exhibits ratiometric offset and sensitivity with supply. The output sensitivity (or scale factor) scales proportionally to the supply voltage. At VS = 3.3 V, output sensitivity is typically 16 mV/g. At VS = 5 V, sensitivity is nominally 24.2 mV/g. Xout zero g bias is nominally equal to VS/2 at all supply voltages. Figure 6. Application Circuit SELF-TEST The fixed fingers in the forcing cells are normally kept at the same potential as that of the movable frame. When the user activates the digital self-test input, the ADXL001 changes the voltage on the fixed fingers in these forcing cells on one side of the moving plate. This potential creates an attractive electrostatic force, causing the sensor to move towards those fixed fingers. The entire signal channel is active, so the sensor displacement causes a change in Xout. The ADXL001 self-test function verifies proper operation of the sensor, interface electronics, and accelerometer channel electronics. Self-test response in g is roughly proportional to the square of the supply voltage. However, when one factors ratiometricity of sensitivity in with supply voltage, the self-test response in voltage is roughly proportional to the cube of the supply voltage. For example, the self-test response for the ADXL001-70 at VS = 5 V is approximately 1.4 V. At VS = 3.3 V, the response is approximately 400 mV. The ST pin should never be exposed to voltages greater than VS + 0.3 V. If this cannot be guaranteed due to the system design (for instance, if there are multiple supply voltages), then a low VF clamping diode between ST and VS is recommended. This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 8 of 10 Preliminary Technical Data ADXL001 LAYOUT, GROUNDING, AND BYPASSING CONSIDERATIONS CLOCK FREQUENCY SUPPLY RESPONSE POWER SUPPLY DECOUPLING In any clocked system, power supply noise near the clock frequency may have consequences at other frequencies. An internal clock typically controls the sensor excitation and the signal demodulator for micromachined accelerometers. 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 1 MHz internal clock frequency (or any harmonic thereof), noise on the supply can cause interference on the ADXL001 output. If additional decoupling is needed, a 50 Ω (or smaller) resistor or ferrite bead can be inserted in the supply line. Additionally, a larger bulk bypass capacitor (in the 1 μF to 4.7 μF range) can be added in parallel to CDC. If the power supply contains high frequency spikes, they may be demodulated and interpreted as acceleration signals. A signal appears at the difference between the noise frequency and the demodulator frequency. If the power supply noise is 100 Hz away from the demodulator clock, there will be an output term at 100 Hz. If the power supply clock is at exactly the same frequency as the accelerometer clock, the term will appear as an offset. If the difference frequency is outside the signal bandwidth, the output filter attenuates it. However, both the power supply clock and the accelerometer clock may vary with time or temperature, which can cause the interference signal to appear in the output filter bandwidth. ELECTROMAGNETIC INTERFERENCE The ADXL001 can be used in areas and applications with high amounts of EMI or with components susceptible to EMI emissions. The fully differential circuitry of the ADXL001 is designed to be robust to such interference. For improved EMI performance, especially in automotive applications, a 1000 pF output capacitor is recommended on the XOUT output. ADXL001 addresses this issue in two ways. First, the high clock frequency, 125 kHz for the output stage, eases the task of choosing a power supply clock frequency such that the difference between it and the accelerometer clock remains well outside the filter bandwidth. Second, ADXL001 has a fully differential signal path, including a pair of electrically isolated, mechanically coupled sensors. The differential sensors eliminate most of the power supply noise before it reaches the demodulator. Good high frequency supply bypassing, such as a ceramic capacitor close to the supply pins, also minimizes the amount of interference. Clock frequency supply response (CFSR) is the ratio of the response at the output to the noise on the power supply near the accelerometer clock frequency or its harmonics. A CFSR of 0.5 means that the signal at the output is half the amplitude of the supply noise. This is analogous to power supply rejection ratio (PSRR), except that the stimulus and the response are at different frequencies. This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 9 of 10 ADXL001 Preliminary Technical Data OUTLINE DIMENSIONS Figure 8. Package Dimensions ORDERING GUIDE Table 5. Ordering Guide Model Branding Package Gee Range Temperature Range ADXL001-70 TBD LCC-8 ± 70g -40°C to 125°C ADXL001-250 TBD LCC-8 ± 250g -40°C to 125°C ADXL001-500 TBD LCC-8 ± 500g -40°C to 125°C ©2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR07510-0-5/08(PrA) This information applies to an ongoing development. Its characteristics and specifications are subject to change without notice. Analog Devices assumes no obligation regarding future manufacturing unless otherwise agreed to in writing. Patents pending. Rev. PrA | Page 10 of 10