Dual-Axis ±1.7 g Accelerometer with SPI Interface ADIS16003 FEATURES GENERAL DESCRIPTION Dual-axis accelerometer SPI® digital output interface Internal temperature sensor Highly integrated; minimal external components; bandwidth externally selectable 1 mg resolution at 60 Hz Externally controlled electrostatic self-test 3.0 V to 5.25 V single-supply operation Low power: <2 mA 3500 g shock survival 7.2 mm × 7.2 mm × 3.6 mm package The ADIS16003 is a low cost, low power, complete dual-axis accelerometer with an integrated serial peripheral interface (SPI). An integrated temperature sensor is also available on the SPI interface. The ADIS16003 measures acceleration with a fullscale range of ±1.7 g (minimum), and it can measure both dynamic acceleration (vibration) and static acceleration (gravity). The typical noise floor is 110 μg/√Hz, allowing signals below 1 mg (60 Hz bandwidth) to be resolved. The bandwidth of the accelerometer is set with optional capacitors CX and CY at the XFILT and YFILT pins. Selection of the two analog input channels is controlled via the serial interface. APPLICATIONS Industrial vibration/motion sensing Platform stabilization Dual-axis tilt sensing Tracking, recording, analysis devices Alarms, security devices An externally driven self-test pin (ST) allows the user to verify the accelerometer functionality. The ADIS16003 is available in a 7.2 mm × 7.2 mm × 3.6 mm, 12-terminal LGA package. FUNCTIONAL BLOCK DIAGRAM VCC SCLK DUAL-AXIS ±1.7g ACCELEROMETER SERIAL INTERFACE DIN DOUT CS CDC TCS COM ST YFILT XFILT CY CX 056463-001 TEMP SENSOR Figure 1. Rev. 0 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 © 2005 Analog Devices, Inc. All rights reserved. ADIS16003 TABLE OF CONTENTS Specifications..................................................................................... 3 Temperature Sensor Serial Interface........................................ 12 Timing Specifications .................................................................. 4 Power Supply Decoupling ......................................................... 13 Circuit and Timing Diagrams..................................................... 5 Setting the Bandwidth Using CXFILT and CYFILT ....................... 13 Absolute Maximum Ratings............................................................ 6 Selecting Filter Characteristics: The Noise/Bandwidth Trade-Off ............................................. 13 ESD Caution.................................................................................. 6 Pin Configuration and Function Descriptions............................. 7 Typical Performance Characteristics ............................................. 8 Theory of Operation ...................................................................... 11 Self-Test........................................................................................ 11 Serial Interface ............................................................................ 11 Applications..................................................................................... 14 Dual-Axis Tilt Sensor ................................................................ 14 Second-Level Assembly ............................................................. 14 Outline Dimensions ....................................................................... 15 Ordering Guide .......................................................................... 15 Accelerometer Serial Interface.................................................. 11 REVISION HISTORY 10/05—Revision 0: Initial Version Rev. 0 | Page 2 of 16 ADIS16003 SPECIFICATIONS TA = –40°C to +125°C, VCC = 5 V, CX, CY = 0 μF, acceleration = 0 g, unless otherwise noted. All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed. Table 1. Parameter ACCELEROMETER SENSOR INPUT Measurement Range 1 Nonlinearity Package Alignment Error Alignment Error Cross Axis Sensitivity ACCELEROMETER SENSITIVITY Sensitivity at XFILT, YFILT Sensitivity Change due to Temperature 2 ZERO g BIAS LEVEL 0 g Voltage at XFILT, YFILT 0 g Offset vs. Temperature ACCELEROMETER NOISE PERFORMANCE Noise Density ACCELEROMETER FREQUENCY RESPONSE 3 CX, CY Range 4 RFILT Tolerance Sensor Resonant Frequency ACCELEROMETER SELF-TEST Logic Input Low Logic Input High ST Input Resistance to COM Output Change at XOUT, YOUT 5 TEMPERATURE SENSOR Accuracy Resolution Update Rate Temperature Conversion Time DIGITAL INPUT Input High Voltage (VINH) T Input Low Voltage (VINL) Input Current Input Capacitance DIGITAL OUTPUT Output High Voltage (VOH) Output Low Voltage (VOL) POWER SUPPLY Operating Voltage Range Quiescent Supply Current Power Down Current Turn-On Time 6 Conditions Each axis Min Typ Max ±0.5 ±1.5 ±0.1 ±2 ±2.5 ±1.7 % of full scale X sensor to Y sensor ±5 Unit g % degrees degrees % Each axis 769 820 ±8 885 LSB/g LSB 1905 2048 ±0.14 2190 LSB LSB/°C Delta from 25°C Each axis @25°C 110 0 24 Self-Test 0 to Self-Test 1 0.8 × VCC 30 323 VCC = 3 V to 5.25 V VCC = 4.75 V to 5.25 V VCC = 3.0 V to 3.6 V VCC = 3.0 V to 5.25 V VIN = 0 V or VCC ISOURCE = 200 μA, VCC = 3.0 V to 5.25 V ISINK = 200 μA 32 5.5 50 614 Cx, Cy = 0.1 μF 1 10 40 μF kΩ kHz 0.2 × VCC V V kΩ LSB 904 ±2 10 400 25 °C Bits μs μs 1 10 V V V μA pF 2.4 2.1 -10 0.8 10 V VCC – 0.5 3.0 FSCLK = 50 kSPS μg/√Hz rms 1.5 1.0 20 0.4 V 5.25 2.0 V mA mA Ms Guaranteed by measurement of initial offset and sensitivity. 2 Defined as the output change from ambient to maximum temperature or ambient to minimum temperature. 3 Actual bandwidth response controlled by user-supplied external capacitor (Cx, Cy). 4 Bandwidth = 1/(2π x 32 kΩ x (2200 pF + C)). For Cx, Cy = 0, bandwidth = 2260 Hz. For Cx, Cy = 10 μF, bandwidth = 0.5 Hz. Min/max values not tested. 5 Self-test response changes as the square of Vcc. 6 Larger values of Cx, Cy increase turn-on time. Turn-on time is approximately 160 x (0.0022 μF + Cx + Cy) + 4 ms, where Cx, Cy are in μF. Rev. 0 | Page 3 of 16 ADIS16003 TIMING SPECIFICATIONS TA = –40°C to +125°C, acceleration = 0 g, unless otherwise noted. Table 2. Parameter 1, 2 fSCLK 3 tCONVERT tACQ t1 t2 4 t34 t4 t5 t6 t7 t8 5 t9 VCC = 3.3 10 2 14.5 tSCLK 1.5 tSCLK 10 60 100 20 20 0.4 × tSCLK 0.4 × tSCLK 80 5 VCC = 5 10 2 14.5 tCSLK 1.5 tSCLK 10 30 75 20 20 0.4 x tSCLK 0.4 x tSCLK 80 5 Unit kHz min MHz max ns min ns max ns max ns min ns min ns min ns min ns max μs typ Description Throughput time = tCONVERT + tACQ = 16 tSCLK TCS/CS to SCLK setup time Delay from TCS/CS until DOUT three-state disabled Data access time after SCLK falling edge Data setup time prior to SCLK rising edge Data hold time after SCLK rising edge SCLK high pulse width SCLK low pulse width TCS/CS rising edge to DOUT high impedance Power-up time from shutdown 1 Guaranteed by design. All input signals are specified with tr and tf = 5 ns (10% to 90% of VCC) and timed from a voltage level of 1.6 V. The 3.3 V operating range spans from 3.0 V to 3.6 V. The 5 V operating range spans from 4.75 V to 5.25 V. 2 See Figure 3 and Figure 4. 3 Mark/space ratio for the SCLK input is 40/60 to 60/40. 4 Measured with the load circuit in Figure 2 and defined as the time required for the output to cross 0.4 V or 2.0 V with VCC = 3.3 V and time for an output to cross 0.8 V or 2.4 V with VCC = 5.0 V. 5 t8 is derived from the measured time taken by the data outputs to change 0.5 V when loaded with the circuit in Figure 2. The measured number is then extrapolated back to remove the effects of charging or discharging the 50 pF capacitor. This means that the time, t8, quoted in the timing characteristics is the true bus relinquish time of the part and is independent of the bus loading. Rev. 0 | Page 4 of 16 ADIS16003 CIRCUIT AND TIMING DIAGRAMS 200μA 1.6V CL 50pF 200μA 05463-002 TO OUTPUT PIN IOL IOH Figure 2. Load Circuit for Digital Output Timing Specifications tACQ tCONVERT CS t6 t1 1 SCLK 2 3 t2 DOUT 4 t7 THREE-STATE 5 6 15 16 t8 t3 THREE-STATE 4 LEADING ZEROS DB9 DB10 DB11 DB0 t4 DONTC ZERO ZERO ZERO ADD0 ONE ZERO 05463-003 t5 DIN PM0 Figure 3. Accelerometer Serial Interface Timing Diagram TCS t6 1 SCLK DOUT THREESTATE 2 3 t3 LEADING ZERO 4 11 t7 15 16 t8 THREE-STATE DB9 DB8 DB0 05463-004 t1 DIN Figure 4. Temperature Serial Interface Timing Diagram Rev. 0 | Page 5 of 16 ADIS16003 ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Acceleration (Any Axis, Unpowered) Acceleration (Any Axis, Powered) VCC All Other Pins Output Short-Circuit Duration (Any Pin to Common) Operating Temperature Range Storage Temperature 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. Rating 3,500 g 3,500 g –0.3 V to +7.0 V (COM – 0.3 V) to (VCC + 0.3 V) Indefinite –40°C to +125°C –65°C to +150°C Table 4. Package Characteristics Package Type 12-Terminal LGA θJA 200°C/W θJC 25°C/W Device Weight 0.3 grams 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. 1.0755 8× BSC 0.670 8× BSC 5.873 2× 0.500 12× BSC Figure 5. Second-Level Assembly Pad Layout Rev. 0 | Page 6 of 16 05463-023 1.127 12× BSC ADIS16003 TCS CS 12 VCC SCLK PIN CONFIGURATION AND FUNCTION DESCRIPTIONS 11 10 1 9 XFILT 8 YFILT 7 NC 3 4 5 6 ST DIN TOP VIEW (Not to Scale) NC 2 COM DOUT NC = NO CONNECT 05463-005 ADIS16003 Figure 6. Pin Configuration Table 5. Pin Function Descriptions Pin No. Mnemonic Description 1 TCS 2 DOUT 3 DIN 4 5, 7 6 8 COM NC ST YFILT 9 XFILT 10 CS 11 12 VCC SCLK Temperature Chip Select. Active low logic input. This input frames the serial data transfer for the temperature sensor output. Data Out, Logic Output. The conversion of the ADIS16003 is provided on this output as a serial data stream. The bits are clocked out on the falling edge of the SCLK input. Data In, Logic Input. Data to be written into the ADIS16003’s control register is provided on this input and is clocked into the register on the rising edge of SCLK. Common. Reference point for all circuitry on the ADIS16003. No Connect. Self-Test Input. Active high logic input. Simulates a nominal 0.75 g test input for diagnostic purpose. Y Channel Filter Node. Used in conjunction with an optional external capacitor to band-limit the ac signal from the accelerometer. X Channel Filter Node. Used in conjunction with an optional external capacitor to band-limit the ac signal from the accelerometer. Chip Select. Active low logic input. This input provides the dual function of initiating the accelerometer conversions on the ADIS16003 and frames the serial data transfer for the accelerometer output. Power Supply Input. The VCC range for the ADIS16003 is from 3.0 V to 5.25 V. Serial Clock, Logic Input. SCLK provides the serial clock for accessing data from the part and writing serial data to the control register. This clock input is also used as the clock source for the ADIS16003’s conversion process. Rev. 0 | Page 7 of 16 ADIS16003 TYPICAL PERFORMANCE CHARACTERISTICS 40 890 35 PERCENTAGE OF POPULATION 850 830 810 790 –20 0 20 40 60 80 100 25 20 15 10 5 05463-006 770 –40 30 05463-009 SENSITIVITY (LSB/g) 870 0 1900 1929 1958 1987 2016 2045 2074 2103 2132 2161 2190 125 OUTPUT (LSB) TEMPERATURE (°C) Figure 10. X-Axis Zero g Bias at 25°C Figure 7. Sensitivity vs. Temperature (AD16003 Soldered to PCB) 2200 40 35 PERCENTAGE OF POPULATION 2100 2050 2000 1900 –40 05463-007 1950 –20 0 20 40 60 80 100 30 25 20 15 10 5 125 05463-010 BIAS LEVEL (LSB) 2150 0 1990 1929 1958 1987 2016 2045 2074 2103 2132 2161 2190 TEMPERATURE (°C) OUTPUT (LSB) Figure 8. Zero g Bias vs. Temperature Figure 11. Y-Axis Zero g Bias at 25°C 2200 45 40 2050 2000 1950 1900 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.7 4.6 4.8 5.0 5.2 5.4 35 30 25 20 15 10 05463-011 PERCENTAGE OF POPULATION 2100 05463-008 BIAS LEVEL (LSB) 2150 5 0 60 VOLTS 70 80 90 100 110 120 130 X-AXIS NOISE DENSITY (μg/ Hz) Figure 9. Zero g Bias vs. Supply Figure 12. X-Axis Noise Density at 25°C Rev. 0 | Page 8 of 16 140 150 ADIS16003 40 30 20 10 0 60 70 80 90 100 110 120 130 140 50 40 30 20 10 05463-015 PERCENTAGE OF POPULATION 60 05463-012 PERCENTAGE OF POPULATION 50 0 150 350 400 450 500 550 Y-AXIS NOISE DENSITY (μg/ Hz) Figure 13. Y-Axis Noise Density at 25°C 650 700 750 800 850 Figure 16. Self-Test at 25°C, VCC at 5.0 V 35 45 40 25 20 15 10 05463-013 5 0 –4.5 –3.5 –2.5 –1.5 –0.5 0.5 1.5 2.5 3.5 4.5 35 30 25 20 15 10 05463-016 PERCENTAGE OF POPULATION 30 PERCENTAGE OF POPULATION 600 OUTPUT (LSB) 5 0 5.5 180 195 210 225 PERCENT SENSITIVITY (%) 240 255 270 285 300 315 OUTPUT (LSB) Figure 14. Z vs. X Cross-Axis Sensitivity Figure 17. Self-Test at 25°C, VCC at 3.3 V 40 750 700 SELF-TEST LEVEL (LSB/g) 30 25 20 15 10 650 600 550 0 –4.5 –3.5 –2.5 –1.5 –0.5 0.5 1.5 2.5 3.5 4.5 450 –40 5.5 PERCENT SENSITIVITY (%) 05463-017 500 5 05463-014 PERCENTAGE OF POPULATION 35 –20 0 20 40 60 80 100 TEMPERATURE (°C) Figure 15. Z vs. Y Cross-Axis Sensitivity Figure 18. Self-Test vs. Temperature VCC at 5.0 V Rev. 0 | Page 9 of 16 125 ADIS16003 800 90 3.3V 80 PERCENTAGE OF POPULATION 600 500 400 300 100 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 70 5V 60 50 40 30 20 10 05463-020 200 05463-018 SELF-TEST LEVEL (LSB) 700 0 1.15 1.20 1.25 1.30 1.35 1.40 1.45 1.50 1.55 1.60 1.65 1.70 1.75 CURRENT (μA) VOLTS Figure 21. Supply Current at 25°C Figure 19. Self-Test vs. Supply Voltage 1.0 1.8 0.8 1.7 0.6 SAMPLING ERROR (dB) 1.5 TA = +25°C TA = +125°C 1.4 1.3 1.2 TA = –40°C 0.4 0.2 0 –0.2 –0.4 1.0 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 05463-021 –0.6 1.1 05463-019 CURRENT (mA) 1.6 –0.8 –1.0 1 10 SAMPLE RATE (kSPS) VOLTS Figure 22. Sampling Error vs. Sample Rate Figure 20. Supply Current vs. Supply Voltage Rev. 0 | Page 10 of 16 100 ADIS16003 THEORY OF OPERATION ACCELEROMETER SERIAL INTERFACE 10 6 2 12 DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 1229 10 5 3 7 9 Accelerometer Control Register MSB DONTC ZERO ZERO ZERO ADD0 ONE ZERO LSB PM0 DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 2048 Table 6. Accelerometer Control Register Bit Functions 1 DIGITAL OUTPUT (IN LSBs) X-AXIS: 2867 Y-AXIS: 2048 9 8 8 4 3 5 7 6 2 1 1 6 4 12 Top View Not to Scale 5 DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 2867 2 11 6 3 4 11 5 7 10 8 8 7 2 3 DIGITAL OUTPUT (IN LSBs) X-AXIS: 1229 Y-AXIS: 2048 4 9 Figure 3 shows the detailed timing diagram for serial interfacing to the accelerometer in the ADIS16003. The serial clock provides the conversion clock. CS initiates the data transfer and conversion process and frames the serial data transfer for the accelerometer output. The accelerometer output is sampled on the second rising edge of the SCLK input after the falling edge of the CS. The conversion requires 16 SCLK cycles to complete. The rising edge of CS puts the bus back into three-state. If CS remains low, the next digital conversion is initiated. The details for the control register bit functions are shown in Table 6. 9 11 1 12 Bit 7 6, 5, 4 3 Mnemonic DONTC ZERO Comments Don’t care. Can be one or zero. These bits should be held low. ADD0 The ADIS16003 is a low cost, low power, complete dual-axis accelerometer with an integrated serial peripheral interface (SPI) and an integrated temperature sensor whose output is also available on the SPI interface. The ADIS16003 is capable of measuring acceleration with a full-scale range of ±1.7 g (minimum). It can also measure both dynamic acceleration (vibration) and static acceleration (gravity). 2 1 0 ONE ZERO PM0 This address bit selects the x-axis or y-axis outputs. Zero selects the x-axis; one selects the y-axis. This bit should be held high. This bit should be held low. This bit selects the operation mode for the accelerometer; set to zero for normal operation and one for power down mode. SELF-TEST Power Down The ST pin controls the self-test feature. When this pin is set to VCC, 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 614 LSB) for VCC = 5.0 V. This pin may be left open-circuit or connected to common in normal use. The ST pin should never be exposed to voltage greater than VCC + 0.3 V. If the system design is such that this condition cannot be guaranteed (for example, multiple supply voltages present), a low VF clamping diode between ST and VCC is recommended. By setting PM0 to one when updating the accelerometer control register, the ADIS16003 goes into a shutdown mode. The information stored in the control register is maintained during shutdown. The ADIS16003 changes modes as soon as the control register is updated. If the part is in shutdown mode and PM0 is changed to zero, then the part powers up on the sixteenth SCLK rising edge. 11 12 05463-024 10 Figure 23. Output Response vs. Orientation SERIAL INTERFACE The serial interface on the ADIS16003 consists of five wires, CS, TCS, SCLK, DIN, and DOUT, with the temperature sensor’s serial interface in parallel with the accelerometer’s serial interface. The CS and TCS are used to select the accelerometer or temperature sensor outputs, respectively. CS and TCS cannot be active at the same time. The SCLK input accesses data from the internal data registers. ADD0 By setting ADD0 to zero when updating the accelerometer control register, the x-axis output is selected. By setting ADD0 to one, the y-axis output is selected. ZERO ZERO is defined as the logic low level. ONE ONE is defined as the logic high level. DONTC DONTC is defined as don’t care; can be a low or high logic level. Rev. 0 | Page 11 of 16 ADIS16003 Accelerometer Conversion Details Every time the accelerometer is sampled, the sampling function discharges the internal CX or CY filtering capacitors by up to 2% of their initial values (assuming no additional external filtering capacitors have been added). The recovery time for the filter capacitor to recharge is approximately 10 μs. Thus, sampling the accelerometer at a rate of 10 kSPS or less does not induce a sampling error. However, as sampling frequencies increase above 10 kSPS, one can expect sampling errors to attenuate the actual acceleration levels. TEMPERATURE SENSOR SERIAL INTERFACE Read Operation Figure 4 shows the timing diagram for a serial read from the temperature sensor. The TCS line enables the SCLK input. Ten bits of data and a leading zero are transferred during a read operation. Read operations occur during streams of 16 clock pulses. The serial data is accessed in a number of bytes if 10 bits of data are being read. At the end of the read operation, the DOUT line remains in the state of the last bit of data clocked out until TCS goes high, at which time the DOUT line from the temperature sensor goes three-state. Write Operation Figure 4 also shows the timing diagram for the serial write to the temperature sensor. The write operation takes place at the same time as the read operation. Data is clocked into the control register on the rising edge of SCLK. DIN should remain low for the entire cycle. Temperature Sensor Control Register MSB ZERO ZERO ZERO ZERO ZERO ZERO ZERO LSB ZERO Table 7. Temperature Sensor Control Register Bit Functions Bit 7 to 0 Mnemonic ZERO Comments All bits should be held low. A conversion is initiated approximately every 350 μs. At this time, the temperature sensor wakes up and performs a temperature conversion. This temperature conversion typically takes 25 μs, at which time the temperature sensor automatically shuts down. The result of the most recent temperature conversion is available in the serial output register at any time. Once the conversion is finished, an internal oscillator starts counting and is designed to time out every 350 μs. The temperature sensor then powers up and does a conversion. Note that if the TCS is brought low every 350 μs (±30%) or less, then the same temperature value is output onto the DOUT line every time without changing. It is recommended that the TCS line not be brought low every 350 μs (±30%) or less. The ±30% covers process variation. The TCS should become active (high to low) outside this range. The device is designed to auto convert every 350 μs. If the temperature sensor is accessed during the conversion process, an internal signal is generated to prevent any update of the temperature value register during the conversion. This prevents the user from reading back spurious data. The design of this feature results in this internal lockout signal being reset only at the start of the next auto conversion. Therefore, if the TCS line goes active before the internal lockout signal is reset to its inactive mode, the internal lockout signal is not reset. To ensure that no lockout signal is set, bring TCS low at a greater time than 350 μs (±30%). As a result, the temperature sensor is not interrupted during a conversion process. In the automatic conversion mode, every time a read or write operation takes place, the internal clock oscillator is restarted at the end of the read or write operation. The result of the conversion is typically available 25 μs later. Reading from the device before conversion is complete provides the same set of data. Table 8. Temperature Sensor Data Format ZERO ZERO is defined as the logic low level. Output Data Format The output data format for the temperature sensor is twos complement. Table 8 shows the relationship between the digital output and the temperature. Temperature Sensor Conversion Details The ADIS16003 features a 10-bit digital temperature sensor that allows an accurate measurement of the ambient device temperature to be made. Temperature –40°C –25°C –0.25°C 0°C +0.25°C +10°C +25°C +50°C +75°C +100°C +125°C The conversion clock for the temperature sensor is internally generated so no external clock is required except when reading from and writing to the serial port. In normal mode, an internal clock oscillator runs the automatic conversion sequence. Rev. 0 | Page 12 of 16 Digital Output (DB9 … DB0) 11 0110 0000 11 1001 1100 11 1111 1111 00 0000 0000 00 0000 0001 00 0010 1000 00 0110 0100 00 1100 1000 01 0010 1100 01 1001 0000 01 1111 0100 ADIS16003 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 may cause interference on the ADIS16003 output. If additional decoupling is needed, ferrite beads may be inserted in the supply line of the ADIS16003. Additionally, a larger bulk bypass capacitor (in the 1 μF to 22 μF range) may be added in parallel to CDC. SETTING THE BANDWIDTH USING CXFILT AND CYFILT The ADIS16003 has provisions for band-limiting the accelerometer. Capacitors can be added at the XFILT and YFILT pins to implement further low-pass filtering for antialiasing and noise reduction. The equation for the 3 dB bandwidth is F−3dB = 1/(2π(32 kΩ) × (C(XFILT, YFILT) + 2200 pF)) or more simply, The ADIS16003 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’s bandwidth). The user should limit bandwidth to the lowest frequency needed by the application in order to maximize the resolution and dynamic range of the accelerometer. With the single pole roll-off characteristic, the typical noise of the ADIS16003 is determined by rmsNoise = (110 μg/√Hz) x (√(BW x 1.6)) At 100 Hz, the noise is rmsNoise = (110 μg/√Hz) x (√(100 x 1.6)) =1.4 mg Often, the peak value of the noise is desired. Peak-to-peak noise can only be estimated by statistical methods. Table 10 is useful for estimating the probabilities of exceeding various peak values, given the rms value. Table 10. Estimation of Peak-to-Peak Noise F−3dB = 5 μF/(C(XFILT, YFILT) + 2200 pF) 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 0 pF for CXFILT and CYFILT is allowable. Peak-to-Peak Value 2 × rms 4 × rms 6 × rms 8 × rms Table 9. Filter Capacitor Selection, CXFILT and CYFILT Bandwidth (Hz) 1 10 50 100 200 400 2250 Capacitor (μF) 4.7 0.47 0.10 0.047 0.022 0.01 0 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, which improves the resolution of the accelerometer. Resolution is dependent on the analog filter bandwidth at XFILT and YFILT. The ADIS16003 has a typical bandwidth of 2.25 kHz with no external filtering. The analog bandwidth may be further decreased to reduce noise and improve resolution. Rev. 0 | Page 13 of 16 Percentage of Time that Noise Exceeds Nominal Peak-to-Peak Value 32% 4.6% 0.27% 0.006% ADIS16003 APPLICATIONS DUAL-AXIS TILT SENSOR RAMP-UP TEMPERATURE TL tL TSMAX TSMIN tS RAMP-DOWN PREHEAT 05463-022 One of the most popular applications of the ADIS16003 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, 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. CRITICAL ZONE TL TO TP tP TP t25°C TO PEAK TIME Figure 24. Acceptable Solder Reflow Profiles Table 11. Converting Acceleration to Tilt 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 follows: Profile Feature Average Ramp Rate (TL to TP) Preheat Minimum Temperature (TSMIN) Maximum Temperature (TSMAX) Time (TSMIN to TSMAX) (ts) PITCH = Asin(AX/1 g) TSMAX to TL Ramp-Up Rate Time Maintained Above Liquidous (TL) Liquidous Temperature (TL) Time (tL) 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. SECOND-LEVEL ASSEMBLY The ADIS16003 may be attached to the second-level assembly board using SN63 (or equivalent) or lead-free solder. Figure 24 and Table 11 provide acceptable solder reflow profiles for each solder type. Note: These profiles may not be the optimum profile for the user’s application. In no case should 260°C be exceeded. It is recommended that the user develop a reflow profile based upon the specific application. In general, keep in mind that the lowest peak temperature and shortest dwell time above the melt temperature of the solder results in less shock and stress to the product. In addition, evaluating the cooling rate and peak temperature can result in a more reliable assembly. Peak Temperature (TP) Time Within 5°C of Actual Peak Temperature (tp) Ramp-Down Rate Time 25°C to Peak Temperature Rev. 0 | Page 14 of 16 Condition Sn63/Pb37 Pb-free 3°C/sec max 3°C/sec max 100°C 150°C 60 sec to 120 sec 150°C 200°C 60 sec to 150 sec 3°C/sec 3°C/sec 183°C 60 sec to 150 sec 240°C + 0°C/–5°C 10 sec to 30 sec 6°C/sec max 6 min max 217°C 60 sec to 150 sec 260°C + 0°C/–5°C 20 sec to 40 sec 6°C/sec max 8 min max ADIS16003 OUTLINE DIMENSIONS 1.302 BSC 7.327 MAX SQ 10 PIN 1 INDICATOR 12 1.00 BSC 9 1 7 3 PIN 1 INDICATOR 0.797 BSC 6 TOP VIEW 0.227 BSC 4 BOTTOM VIEW 0.373 BSC 5.00 TYP 3.60 MAX Figure 25. 12-Terminal Land Grid Array [LGA] (CC-12) Dimensions shown in millimeters ORDERING GUIDE Model ADIS16003CCCZ 1 ADIS16003/PCB 1 Temperature Range −40°C to +125°C Package Description 12-Terminal Land Grid Array (LGA) Evaluation Board Z = Pb-free part. Rev. 0 | Page 15 of 16 Package Option CC-12 ADIS16003 NOTES © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05463-0-10/05(0) Rev. 0 | Page 16 of 16