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Dual-Axis 1.7 g Accelerometer with SPI Interface ADIS16003
FEATURES
Dual-axis accelerometer SPI(R) 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 x 7.2 mm x 3.6 mm package
GENERAL DESCRIPTION
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 g/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. An externally driven self-test pin (ST) allows the user to verify the accelerometer functionality. The ADIS16003 is available in a 7.2 mm x 7.2 mm x 3.6 mm, 12-terminal LGA package.
APPLICATIONS
Industrial vibration/motion sensing Platform stabilization Dual-axis tilt sensing Tracking, recording, analysis devices Alarms, security devices
FUNCTIONAL BLOCK DIAGRAM
VCC
SCLK DUAL-AXIS 1.7g ACCELEROMETER CDC SERIAL INTERFACE DIN DOUT CS TCS
TEMP SENSOR
COM
ST
YFILT CY
XFILT CX
056463-001
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 (c) 2005 Analog Devices, Inc. All rights reserved.
ADIS16003 TABLE OF CONTENTS
Specifications..................................................................................... 3 Timing Specifications .................................................................. 4 Circuit and Timing Diagrams..................................................... 5 Absolute Maximum Ratings............................................................ 6 ESD Caution.................................................................................. 6 Pin Configuration and Function Descriptions............................. 7 Typical Performance Characteristics ............................................. 8 Theory of Operation ...................................................................... 11 Self-Test........................................................................................ 11 Serial Interface ............................................................................ 11 Accelerometer Serial Interface.................................................. 11 Temperature Sensor Serial Interface........................................ 12 Power Supply Decoupling ......................................................... 13 Setting the Bandwidth Using CXFILT and CYFILT ....................... 13 Selecting Filter Characteristics: The Noise/Bandwidth Trade-Off ............................................. 13 Applications..................................................................................... 14 Dual-Axis Tilt Sensor ................................................................ 14 Second-Level Assembly ............................................................. 14 Outline Dimensions ....................................................................... 15 Ordering Guide .......................................................................... 15
REVISION HISTORY
10/05--Revision 0: Initial Version
Rev. 0 | Page 2 of 16
ADIS16003 SPECIFICATIONS
TA = -40C to +125C, VCC = 5 V, CX, CY = 0 F, 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, YOUTT 5 TEMPERATURE SENSOR Accuracy Resolution Update Rate Temperature Conversion Time DIGITAL INPUT Input High Voltage (VINH) 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
1
Conditions Each axis % of full scale X sensor to Y sensor Each axis
Min 1.7
Typ
Max
Unit g % degrees degrees % LSB/g LSB LSB LSB/C g/Hz rms
0.5 1.5 0.1 2 769 820 8 2048 0.14 110 0 24
2.5
5 885
Delta from 25C Each axis 1905
2190
@25C
32 5.5
10 40
F k kHz V V k LSB C Bits s s V V V A pF V
0.2 x VCC 0.8 x VCC 30 323 50 614 2 10 400 25 2.4 2.1 -10 1 10 0.8 10
Self-Test 0 to Self-Test 1 VCC = 3 V to 5.25 V
904
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 A, VCC = 3.0 V to 5.25 V ISINK = 200 A
VCC - 0.5 0.4 3.0 5.25 2.0 V V mA mA Ms
FSCLK = 50 kSPS Cx, Cy = 0.1 F
1.5 1.0 20
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/(2 x 32 k x (2200 pF + C)). For Cx, Cy = 0, bandwidth = 2260 Hz. For Cx, Cy = 10 F, 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 F + Cx + Cy) + 4 ms, where Cx, Cy are in F. Rev. 0 | Page 3 of 16
ADIS16003
TIMING SPECIFICATIONS
TA = -40C to +125C, 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
1
VCC = 3.3 10 2 14.5 tSCLK 1.5 tSCLK 10 60 100 20 20 0.4 x tSCLK 0.4 x 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
Description
ns min ns max ns max ns min ns min ns min ns min ns max s typ
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
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
200A IOL
TO OUTPUT PIN
1.6V CL 50pF 200A IOH
05463-002
Figure 2. Load Circuit for Digital Output Timing Specifications
tACQ
tCONVERT
CS
t1
SCLK 1 2
t6
3 4 5 6 15 16
t2
DOUT THREE-STATE
t7
4 LEADING ZEROS
t3
DB11 DB10 DB9 DB0
t8
THREE-STATE
t4
DIN DONTC ZERO ZERO ZERO ADD0 ONE ZERO PM0
05463-003
t5
Figure 3. Accelerometer Serial Interface Timing Diagram
TCS
t1
SCLK THREESTATE 1 2
t6
3 4 11 15 16
t3
LEADING ZERO DB9
t7
DB8 DB0
t8
THREE-STATE
DOUT
DIN
Figure 4. Temperature Serial Interface Timing Diagram
Rev. 0 | Page 5 of 16
05463-004
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 Rating 3,500 g 3,500 g -0.3 V to +7.0 V (COM - 0.3 V) to (VCC + 0.3 V) Indefinite -40C to +125C -65C to +150C
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.
Table 4. Package Characteristics
Package Type 12-Terminal LGA JA 200C/W JC 25C/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 8x BSC
0.670 8x BSC
5.873 2x
1.127 12x BSC
0.500 12x BSC
Figure 5. Second-Level Assembly Pad Layout
Rev. 0 | Page 6 of 16
05463-023
ADIS16003 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
SCLK VCC
12 11 10
CS
TCS
1
9
XFILT
ADIS16003
DOUT
2
TOP VIEW (Not to Scale)
8
YFILT
DIN
3
7
NC
4
5
6
NC
COM
ST
NC = NO CONNECT
Figure 6. Pin Configuration
Table 5. Pin Function Descriptions
Pin No. 1 2 3 4 5, 7 6 8 9 10 11 12 Mnemonic TCS DOUT DIN COM NC ST YFILT XFILT CS VCC SCLK Description 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
05463-005
ADIS16003 TYPICAL PERFORMANCE CHARACTERISTICS
890
40 35
PERCENTAGE OF POPULATION
870
30 25 20 15 10
05463-009
SENSITIVITY (LSB/g)
850
830
810
790
05463-006
5 0 1900 1929 1958 1987 2016 2045 2074 2103 2132 2161 2190 OUTPUT (LSB)
770 -40
-20
0
20
40
60
80
100
125
TEMPERATURE (C)
Figure 7. Sensitivity vs. Temperature (AD16003 Soldered to PCB)
2200
Figure 10. X-Axis Zero g Bias at 25C
40
2150
PERCENTAGE OF POPULATION
35 30 25 20 15 10
05463-010
BIAS LEVEL (LSB)
2100
2050
2000
1950
05463-007
5 0 1990 1929 1958 1987 2016 2045 2074 2103 2132 2161 2190 OUTPUT (LSB)
1900 -40
-20
0
20
40
60
80
100
125
TEMPERATURE (C)
Figure 8. Zero g Bias vs. Temperature
Figure 11. Y-Axis Zero g Bias at 25C
45 40
PERCENTAGE OF POPULATION
05463-008
2200
2150
35 30 25 20 15 10 5 0 60 70 80 90 100 110 120 130 140 150 X-AXIS NOISE DENSITY (g/ Hz)
05463-011
BIAS LEVEL (LSB)
2100
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 VOLTS
Figure 9. Zero g Bias vs. Supply
Figure 12. X-Axis Noise Density at 25C
Rev. 0 | Page 8 of 16
ADIS16003
50 60
PERCENTAGE OF POPULATION
40
PERCENTAGE OF POPULATION
05463-012
50
40
30
30
20
20
10
10
05463-015
0 60 70 80 90 100 110 120 130 140 150 Y-AXIS NOISE DENSITY (g/ Hz)
0 350 400 450 500 550 600 650 700 750 800 850 OUTPUT (LSB)
Figure 13. Y-Axis Noise Density at 25C
35 30
PERCENTAGE OF POPULATION PERCENTAGE OF POPULATION
Figure 16. Self-Test at 25C, VCC at 5.0 V
45 40 35 30 25 20 15 10 5 0 180 195 210 225 240 255 270 285 300 315 OUTPUT (LSB)
05463-016
25
20
15
10
0 -4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 PERCENT SENSITIVITY (%)
Figure 14. Z vs. X Cross-Axis Sensitivity
40 35
PERCENTAGE OF POPULATION
05463-013
5
Figure 17. Self-Test at 25C, VCC at 3.3 V
750
700
SELF-TEST LEVEL (LSB/g)
05463-014
30 25 20 15 10 5 0 -4.5 -3.5 -2.5 -1.5 -0.5 0.5 1.5 2.5 3.5 4.5 5.5 PERCENT SENSITIVITY (%)
650
600
550
500
05463-017
450 -40
-20
0
20
40
60
80
100
125
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
ADIS16003
800
90 3.3V 80
700
PERCENTAGE OF POPULATION
SELF-TEST LEVEL (LSB)
70 60 50 40 30 20
05463-020
600
5V
500
400
300
05463-018
200 100 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 VOLTS
10 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 (A)
Figure 19. Self-Test vs. Supply Voltage
1.8 1.7 1.6
CURRENT (mA)
Figure 21. Supply Current at 25C
1.0 0.8 0.6
SAMPLING ERROR (dB)
1.5 1.4 1.3 1.2 1.1
TA = +125C
TA = +25C
0.4 0.2 0 -0.2 -0.4 -0.6
TA = -40C
05463-019
-0.8 -1.0 1 10 SAMPLE RATE (kSPS)
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 VOLTS
100
Figure 20. Supply Current vs. Supply Voltage
Figure 22. Sampling Error vs. Sample Rate
Rev. 0 | Page 10 of 16
05463-021
ADIS16003 THEORY OF OPERATION
ACCELEROMETER SERIAL INTERFACE
12 11 10 DIGITAL OUTPUT (IN LSBs) X-AXIS: 1229 Y-AXIS: 2048
4 9 8 7
5
6 3 2 1
DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 2867
Top View Not to Scale
DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 1229
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.
1
2
3
10
7
8
9
11
12
1
2
3 6 5 4
7
8
9
10
4
11
5
12
6
4 5 6
Accelerometer Control Register
MSB DONTC
DIGITAL OUTPUT (IN LSBs) X-AXIS: 2048 Y-AXIS: 2048
ZERO
ZERO
ZERO
ADD0
ONE
ZERO
LSB PM0
7
DIGITAL OUTPUT (IN LSBs) X-AXIS: 2867 Y-AXIS: 2048
8
2
3
Table 6. Accelerometer Control Register Bit Functions
Bit 7 6, 5, 4 3 Mnemonic DONTC ZERO ADD0 Comments Don't care. Can be one or zero. These bits should be held low. 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.
9
10
11
12
1
Figure 23. Output Response vs. Orientation
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).
05463-024
2 1 0
ONE ZERO PM0
SELF-TEST
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.
Power Down
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.
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.
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.
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 s. 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. A conversion is initiated approximately every 350 s. At this time, the temperature sensor wakes up and performs a temperature conversion. This temperature conversion typically takes 25 s, 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 s. The temperature sensor then powers up and does a conversion. Note that if the TCS is brought low every 350 s (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 s (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 s. 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 s (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 s later. Reading from the device before conversion is complete provides the same set of data. Table 8. Temperature Sensor Data Format
Temperature -40C -25C -0.25C 0C +0.25C +10C +25C +50C +75C +100C +125C 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
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.
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. 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
ADIS16003
POWER SUPPLY DECOUPLING
For most applications, a single 0.1 F 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 F to 22 F range) may be added in parallel to CDC. The ADIS16003 noise has the characteristics of white Gaussian noise, which contributes equally at all frequencies and is described in terms of g/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 g/Hz) x ((BW x 1.6)) At 100 Hz, the noise is rmsNoise = (110 g/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
Peak-to-Peak Value 2 x rms 4 x rms 6 x rms 8 x rms Percentage of Time that Noise Exceeds Nominal Peak-to-Peak Value 32% 4.6% 0.27% 0.006%
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/(2(32 k) x (C(XFILT, YFILT) + 2200 pF)) or more simply, F-3dB = 5 F/(C(XFILT, YFILT) + 2200 pF) The tolerance of the internal resistor (RFILT) can vary typically as much as 25% of its nominal value (32 k); thus, the bandwidth varies accordingly. A minimum capacitance of 0 pF for CXFILT and CYFILT is allowable. Table 9. Filter Capacitor Selection, CXFILT and CYFILT
Bandwidth (Hz) 1 10 50 100 200 400 2250 Capacitor (F) 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
ADIS16003 APPLICATIONS
DUAL-AXIS TILT SENSOR
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.
TP RAMP-UP
tP
CRITICAL ZONE TL TO TP
TEMPERATURE
TL
TSMAX TSMIN
tL
tS
PREHEAT
RAMP-DOWN
05463-022
t25C TO PEAK
TIME
Figure 24. Acceptable Solder Reflow Profiles
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: 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.
Table 11.
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 5C of Actual Peak Temperature (tp) Ramp-Down Rate Time 25C to Peak Temperature Condition Sn63/Pb37 Pb-free 3C/sec max 3C/sec max 100C 150C 60 sec to 120 sec 3C/sec 150C 200C 60 sec to 150 sec 3C/sec
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 260C 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.
183C 60 sec to 150 sec 240C + 0C/-5C 10 sec to 30 sec 6C/sec max 6 min max
217C 60 sec to 150 sec 260C + 0C/-5C 20 sec to 40 sec 6C/sec max 8 min max
Rev. 0 | Page 14 of 16
ADIS16003 OUTLINE DIMENSIONS
7.327 MAX SQ 1.302 BSC
10
PIN 1 INDICATOR
12
1.00 BSC
9 1
PIN 1 INDICATOR
0.797 BSC
7 6 4
3
TOP VIEW
5.00 TYP
0.227 BSC
BOTTOM VIEW
0.373 BSC
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 -40C to +125C
Package Description 12-Terminal Land Grid Array (LGA) Evaluation Board
Package Option CC-12
Z = Pb-free part.
Rev. 0 | Page 15 of 16
ADIS16003 NOTES
(c) 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

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