Small and Thin ±5 g iMEMS® Accelerometer
`ADXL320
`
`FEATURES
`Small and thin
`4 mm × 4 mm × 1.45 mm LFCSP package
`2 mg resolution at 60 Hz
`Wide supply voltage range: 2.4 V to 5.25 V
`Low power: 350 μA at VS = 2.4 V (typ)
`Good zero g bias stability
`Good sensitivity accuracy
`X-axis and Y-axis aligned to within 0.1° (typ)
`BW adjustment with a single capacitor
`Single-supply operation
`10,000 g shock survival
`Compatible with Sn/Pb and Pb-free solder processes
`
`APPLICATIONS
`Cost-sensitive motion- and tilt-sensing applications
`Smart hand-held devices
`Mobile phones
`Sports and health-related devices
`PC security and PC peripherals
`
`GENERAL DESCRIPTION
`The ADXL320 is a low cost, low power, complete dual-axis
`accelerometer with signal conditioned voltage outputs, which is
`all on a single monolithic IC. The product measures
`acceleration with a full-scale range of ±5 g (typical). It can also
`measure both dynamic acceleration (vibration) and static
`acceleration (gravity).
`
`The ADXL320’s typical noise floor is 250 μg/√Hz, allowing
`signals below 2 mg to be resolved in tilt-sensing applications
`using narrow bandwidths (<60 Hz).
`
`The user selects the bandwidth of the accelerometer using
`capacitors CX and CY at the XOUT and YOUT pins. Bandwidths of
`0.5 Hz to 2.5 kHz may be selected to suit the application.
`
`The ADXL320 is available in a very thin 4 mm × 4 mm ×
`1.45 mm, 16-lead, plastic LFCSP.
`
`FUNCTIONAL BLOCK DIAGRAM
`+3V
`
`VS
`
`ADXL320
`
`CDC
`
`AC
`AMP
`
`DEMOD
`
`OUTPUT
`AMP
`
`OUTPUT
`AMP
`
`RFILT
`32kΩ
`
`RFILT
`32kΩ
`
`04993-001
`
`XOUT
`CX
`
`YOUT
`CY
`
`SENSOR
`
`COM
`
`ST
`
`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: 781.326.8703
`© 2007 Analog Devices, Inc. All rights reserved.
`
`IPR2020-01192
`Apple EX1031 Page 1
`
`

`

`ADXL320
`
`
`
`TABLE OF CONTENTS
`Specifications..................................................................................... 3
`Absolute Maximum Ratings............................................................ 4
`ESD Caution.................................................................................. 4
`Pin Configuration and Function Descriptions............................. 5
`Typical Performance Characteristics (VS = 3.0 V)....................... 7
`Theory of Operation ...................................................................... 11
`Performance ................................................................................ 11
`Applications..................................................................................... 12
`Power Supply Decoupling ......................................................... 12
`
`
`REVISION HISTORY
`9/04—Revision 0: Initial Version
`
`Setting the Bandwidth Using CX and CY ................................. 12
`Self-Test ....................................................................................... 12
`Design Trade-Offs for Selecting Filter Characteristics: The
`Noise/BW Trade-Off.................................................................. 12
`Use with Operating Voltages Other than 3 V............................. 13
`Use as a Dual-Axis Tilt Sensor ................................................. 13
`Outline Dimensions....................................................................... 14
`Ordering Guide .......................................................................... 14
`
`Rev. 0 | Page 2 of 16
`
`IPR2020-01192
`Apple EX1031 Page 2
`
`

`

`
`
`
`
`SPECIFICATIONS1
`TA = 25°C, VS = 3 V, CX = CY = 0.1 μF, Acceleration = 0 g, unless otherwise noted.
`
`ADXL320
`
`
`Table 1.
`Parameter
`SENSOR INPUT
`Measurement Range
`Nonlinearity
`Package Alignment Error
`Alignment Error
`Cross Axis Sensitivity
`SENSITIVITY (RATIOMETRIC)2
`Sensitivity at XOUT, YOUT
`Sensitivity Change due to Temperature3
`ZERO g BIAS LEVEL (RATIOMETRIC)
`0 g Voltage at XOUT, YOUT
`0 g Offset Versus Temperature
`NOISE PERFORMANCE
`Noise Density
`FREQUENCY RESPONSE4
`CX, CY Range5
`RFILT Tolerance
`Sensor Resonant Frequency
`SELF-TESTT
`6
`Logic Input Low
`Logic Input High
`ST Input Resistance to Ground
`Output Change at XOUT, YOUT
`OUTPUT AMPLIFIER
`Output Swing Low
`Output Swing High
`POWER SUPPLY
`Operating Voltage Range
`Quiescent Supply Current
`Turn-On Time7
`TEMPERATURE
`Operating Temperature Range
`
`
`
`Conditions
`Each axis
`
`% of full scale
`
`X sensor to Y sensor
`
`Each axis
`VS = 3 V
`VS = 3 V
`Each axis
`VS = 3 V
`
`
`@ 25°C
`
`
`
`
`
`
`
`
`Self-test 0 to 1
`
`No load
`No load
`
`
`
`
`
`
`
`Min
`
`
`
`
`
`
`
`156
`
`
`1.3
`
`
`
`
`0.002
`
`
`
`
`
`
`
`
`
`
`
`2.4
`
`
`
`−20
`
`Typ
`
`±5
`±0.2
`±1
`±0.1
`±2
`
`174
`0.01
`
`1.5
`±0.6
`
`250
`
`Max
`
`
`
`
`
`
`
`192
`
`
`1.7
`
`
`
`
`
`32 ± 15%
`5.5
`
`10
`
`
`
`0.6
`2.4
`50
`55
`
`0.3
`2.5
`
`
`0.48
`20
`
`
`
`
`
`
`
`
`
`
`
`5.25
`
`
`
`70
`
`Unit
`
`g
`%
`Degrees
`Degrees
`%
`
`mV/g
`%/°C
`
`V
`mg/°C
`
`μg/√Hz rms
`
`μF
`kΩ
`kHz
`
`V
`V
`kΩ
`mV
`
`V
`V
`
`V
`mA
`ms
`
`°C
`
`
`1 All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed.
`2 Sensitivity is essentially ratiometric to VS. For VS = 2.7 V to 3.3 V, sensitivity is 154 mV/V/g to 194 mV/V/g typical.
`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.
`
`
`
`
`Rev. 0 | Page 3 of 16
`
`IPR2020-01192
`Apple EX1031 Page 3
`
`

`

`ADXL320
`
`
`
`ABSOLUTE MAXIMUM RATINGS
`
`Table 2.
`Parameter
`Acceleration (Any Axis, Unpowered)
`Acceleration (Any Axis, Powered)
`VS
`All Other Pins
`
`Rating
`10,000 g
`10,000 g
`−0.3 V to +7.0 V
`(COM − 0.3 V) to
`(VS + 0.3 V)
`
`Output Short-Circuit Duration
`(Any Pin to Common)
`Operating Temperature Range
`Storage Temperature
`
`
`Indefinite
`−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.
`
`
`
`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.
`
`
`
`
`Rev. 0 | Page 4 of 16
`
`IPR2020-01192
`Apple EX1031 Page 4
`
`

`

`
`
`
`
`PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
`
`
`
`
`ADXL320
`
`XOUT
`
`NC
`
`YOUT
`
`NC
`
`
`
`04993-022
`
`NC
`
`VS
`
`VS
`
`NC
`
`ADXL320
`TOP VIEW
`(Not to Scale)
`
`NC
`
`ST
`
`COM
`
`NC
`
`COM COM COM NC
`NC = NO CONNECT
`
`Figure 2. Pin Configuration
`
`Description
`Do Not Connect
`Self-Test
`Common
`Do Not Connect
`Common
`Common
`Common
`Do Not Connect
`Do Not Connect
`Y Channel Output
`Do Not Connect
`X Channel Output
`Do Not Connect
`2.4 V to 5.25 V
`2.4 V to 5.25 V
`Do Not Connect
`
`Rev. 0 | Page 5 of 16
`
`
`
`Table 3. Pin Function Descriptions
`Pin No.
`Mnemonic
`1
`NC
`2
`ST
`3
`COM
`4
`NC
`5
`COM
`6
`COM
`7
`COM
`8
`NC
`9
`NC
`10
`YOUT
`11
`NC
`12
`XOUT
`13
`NC
`14
`VS
`15
`VS
`16
`NC
`
`
`IPR2020-01192
`Apple EX1031 Page 5
`
`

`

`ADXL320
`
`
`
`
`tP
`
`CRITICAL ZONE
`TL TO TP
`
`RAMP-UP
`
`tL
`
`04993-002
`
`
`
`tS
`PREHEAT
`
`RAMP-DOWN
`
`t25°C TO PEAK
`
`TIME
`
`Figure 3. Recommended Soldering Profile
`
`TSMAX
`
`TSMIN
`
`TP
`
`TL
`
`TEMPERATURE
`
`
`Table 4. 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
`
`
`Sn63/Pb37
`3°C/second max
`
`100°C
`150°C
`60 − 120 seconds
`
`3°C/second
`
`183°C
`60 − 150 seconds
`240°C + 0°C/−5°C
`10 − 30 seconds
`6°C/second max
`6 minutes max
`
`Pb-Free
`3°C/second max
`
`150°C
`200°C
`60 − 150 seconds
`
`3°C/second
`
`217°C
`60 − 150 seconds
`260°C + 0°C/−5°C
`20 − 40 seconds
`6°C/second max
`8 minutes max
`
`Rev. 0 | Page 6 of 16
`
`IPR2020-01192
`Apple EX1031 Page 6
`
`

`

`
`
`
`
`TYPICAL PERFORMANCE CHARACTERISTICS (VS = 3.0 V)
`
`ADXL320
`
`04993-006
`
`
`
`04993-007
`
`
`
`04993-008
`
`
`
`1.40 1.42 1.44 1.46 1.48 1.50 1.52 1.54 1.56 1.58 1.60
`OUTPUT (V)
`
`25
`
`20
`
`15
`
`10
`
`5
`
`0
`
`% OF POPULATION
`
`04993-003
`
`
`
`1.40 1.42 1.44 1.46 1.48 1.50 1.52 1.54 1.56 1.58 1.60
`OUTPUT (V)
`
`25
`
`20
`
`15
`
`10
`
`5
`
`0
`
`Figure 4. X-Axis Zero g Bias Deviation from Ideal at 25°C
`
`Figure 7. Y-Axis Zero g Bias Deviation from Ideal at 25°C
`
`–2.8–2.4–2.0–1.6–1.2–0.8–0.4 0 0.4 0.8 1.2 1.6 2.0 2.4 2.8
`TEMPERATURE COEFFICIENT (mg/°C)
`
`Figure 8. Y-Axis Zero g Bias Temperature Coefficient
`
`164
`
`166
`
`168
`
`170
`172
`174
`176
`178
`SENSITIVITY (mV/g)
`
`180
`
`182
`
`184
`
`35
`
`30
`
`25
`
`20
`
`15
`
`10
`
`05
`
`70
`
`60
`
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`% OF POPULATION
`
`% OF POPULATION
`
`04993-004
`
`
`
`04993-005
`
`
`
`–2.8–2.4–2.0–1.6–1.2–0.8–0.4 0 0.4 0.8 1.2 1.6 2.0 2.4 2.8
`TEMPERATURE COEFFICIENT (mg/°C)
`
`Figure 5. X-Axis Zero g Bias Temperature Coefficient
`
`164
`
`166
`
`168
`
`170
`172
`174
`176
`178
`SENSITIVITY (mV/g)
`
`180
`
`182
`
`184
`
`35
`
`30
`
`25
`
`20
`
`15
`
`10
`
`05
`
`90
`
`80
`
`70
`
`60
`
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`Figure 6. X-Axis Sensitivity at 25°C
`
`Figure 9. Y-Axis Sensitivity at 25°C
`
`% OF POPULATION
`
`% OF POPULATION
`
`% OF POPULATION
`
`Rev. 0 | Page 7 of 16
`
`IPR2020-01192
`Apple EX1031 Page 7
`
`

`

`04993-012
`
`40
`30
`20
`10
`TEMPERATURE (°C)
`
`50
`
`60
`
`70
`
`80
`
`
`
`0.180
`
`0.179
`
`0.178
`
`0.177
`
`0.176
`
`0.175
`
`0.174
`
`0.173
`
`0.172
`
`0.171
`
`SENSITIVITY (V/g)
`
`0.170
`–30 –20 –10
`
`0
`
`04993-009
`
`40
`30
`20
`10
`TEMPERATURE (°C)
`
`50
`
`60
`
`70
`
`80
`
`
`
`ADXL320
`
`
`
`1.54
`
`1.53
`
`1.52
`
`1.51
`
`1.50
`
`1.49
`
`1.48
`
`1.47
`
`OUTPUT (SCALE = 174mV/g)
`
`1.46
`–30 –20 –10
`
`0
`
`Figure 10. Zero g Bias vs. Temperature—Parts Soldered to PCB
`
`Figure 13. Sensitivity vs. Temperature—Parts Soldered to PCB
`
`30
`
`25
`
`20
`
`15
`
`10
`
`% OF POPULATION
`
`35
`
`30
`
`25
`
`20
`
`15
`
`10
`
`% OF POPULATION
`
`04993-013
`
`04993-010
`
`170
`
`190
`
`210
`
`230
`
`290
`270
`250
`NOISE ug/ Hz
`
`310
`
`330
`
`350
`
`
`
`Figure 14. Y-Axis Noise Density at 25°C
`
`04993-014
`
`
`
`–5
`
`–4
`
`–3
`
`2
`1
`0
`–1
`–2
`PERCENT SENSITIVITY (%)
`
`3
`
`4
`
`5
`
`5 0
`
`30
`
`25
`
`20
`
`15
`
`10
`
`5 0
`
`% OF POPULATION
`
`170
`
`190
`
`210
`
`230
`
`290
`270
`250
`NOISE ug/ Hz
`
`310
`
`330
`
`350
`
`
`
`Figure 11. X-Axis Noise Density at 25°C
`
`04993-011
`
`
`
`–5
`
`–4
`
`–3
`
`2
`1
`0
`–1
`–2
`PERCENT SENSITIVITY (%)
`
`3
`
`4
`
`5
`
`5 0
`
`25
`
`20
`
`15
`
`10
`
`5
`
`0
`
`% OF POPULATION
`
`Figure 12. Z vs. X Cross-Axis Sensitivity
`
`Figure 15. Z vs. Y Cross-Axis Sensitivity
`
`Rev. 0 | Page 8 of 16
`
`IPR2020-01192
`Apple EX1031 Page 8
`
`

`

`ADXL320
`
`
`
`04993-017
`
`35
`
`40
`
`45
`
`50
`55
`60
`SELF-TEST (mV)
`
`65
`
`70
`
`75
`
`60
`
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`% OF POPULATION
`
`
`
`04993-015
`
`35
`
`40
`
`45
`
`50
`55
`60
`SELF-TEST (mV)
`
`65
`
`70
`
`75
`
`Figure 16. X-Axis Self-Test Response at 25°C
`
`Figure 18. Y-Axis Self-Test Response at 25°C
`
`
`
`04993-020
`
`Figure 19. Turn-On Time—CX, CY = 0.1 μF, Time Scale = 2 ms/DIV
`
`04993-016
`
`
`
`420 430 440 450 460 470 480 490 500 510 520 530
`CURRENT (μA)
`
`Figure 17. Supply Current at 25°C
`
`
`
`
`
`
`
`
`
`
`
`Rev. 0 | Page 9 of 16
`
`60
`
`50
`
`40
`
`30
`
`20
`
`10
`
`0
`
`40
`
`35
`
`30
`
`25
`
`20
`
`15
`
`10
`
`5 0
`
`% OF POPULATION
`
`% OF POPULATION
`
`
`
`
`
`
`
`IPR2020-01192
`Apple EX1031 Page 9
`
`

`

`XL
`320J
`#1234
`5678P
`
`XOUT = 1.326V
`YOUT = 1.500V
`
`XOUT = 1.500V
`YOUT = 1.326V
`
`XL
`320J
`#1234
`5678P
`
`5678P
`#1234
`320J
`XL
`
`XOUT = 1.500V
`YOUT = 1.674V
`
`
`
`04993-018
`
`XOUT = 1.500V
`YOUT = 1.500V
`
`5678P
`#1234
`320J
`XL
`
`XOUT = 1.674V
`YOUT = 1.50V
`
`EARTH'S SURFACE
`
`Figure 20. Output Response vs. Orientation
`
`ADXL320
`
`
`
`
`
`
`
`Rev. 0 | Page 10 of 16
`
`IPR2020-01192
`Apple EX1031 Page 10
`
`

`

`
`
`
`
`THEORY OF OPERATION
`The ADXL320 is a complete acceleration measurement system
`on a single monolithic IC. The ADXL320 has a measurement
`range of ±5 g. It contains a polysilicon surface-micromachined
`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
`accelerometer measures static acceleration forces, such as
`gravity, which allows it to be used as a tilt sensor.
`
`The sensor is a polysilicon surface-micromachined structure
`built on top of a 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.
`
`
`
`ADXL320
`
`The demodulator’s output is amplified and brought off-chip
`through a 32 kΩ resistor. The user then sets 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
`high performance is built-in. As a result, there is neither
`quantization error nor nonmonotonic behavior, and
`temperature hysteresis is very low (typically less than 3 mg over
`the −20°C to +70°C temperature range).
`
`Figure 10 shows the zero g output performance of eight parts
`(X- and Y-axis) over a −20°C to +70°C temperature range.
`
`Figure 13 demonstrates the typical sensitivity shift over
`temperature for supply voltages of 3 V. This is typically better
`than ±1% over the −20°C to +70°C temperature range.
`
`Rev. 0 | Page 11 of 16
`
`IPR2020-01192
`Apple EX1031 Page 11
`
`

`

`ADXL320
`
`
`
`APPLICATIONS
`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
`ADXL320 output. If additional decoupling is needed, a 100 Ω
`(or smaller) resistor or ferrite bead may be inserted in the
`supply line. Additionally, a larger bulk bypass capacitor (in the
`1 μF to 4.7 μF range) may be added in parallel to CDC.
`
`SETTING THE BANDWIDTH USING CX AND CY
`The ADXL320 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) typically varies as
`much as ±15% of its nominal value (32 kΩ), and the bandwidth
`varies accordingly. A minimum capacitance of 2000 pF for CX
`and CY is required in all cases.
`Table 5. Filter Capacitor Selection, CX and CY
`Bandwidth (Hz)
`Capacitor (μF)
`1
`4.7
`10
`0.47
`50
`0.10
`100
`0.05
`200
`0.027
`500
`0.01
`
`SELF-TEST
`The ST pin controls the self-test feature. When this pin is set to
`VS, an electrostatic force is exerted on the accelerometer beam.
`The resulting movement of the beam allows the user to test if
`the accelerometer is functional. The typical change in output is
`315 mg (corresponding to 55 mV). This pin may be left open-
`circuit or connected to common (COM) in normal use.
`
`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.
`
`DESIGN TRADE-OFFS FOR SELECTING FILTER
`CHARACTERISTICS: THE NOISE/BW 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 XOUT and YOUT.
`
`The output of the ADXL320 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
`A/D sampling frequency to minimize aliasing. The analog
`bandwidth may be further decreased to reduce noise and
`improve resolution.
`
`The ADXL320 noise has the characteristics of white Gaussian
`noise, which contributes equally at all frequencies and is
`described in terms of μg/√Hz (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 ADXL320 is determined by
`
`rmsNoise
`
`=
`
`(250
`
`μg/
`
`Hz
`
`()
`×
`
`BW
`
`×
`
`)1.6
`
`
`
`At 100 Hz bandwidth the noise will be
`
`rmsNoise
`
`=
`
`(250
`
`μg/
`
`Hz
`
`()
`×
`
`100
`
`×
`
`)1.6
`
`=
`
`3.2
`
`mg
`
`
`
`Often, the peak value of the noise is desired. Peak-to-peak noise
`can only be estimated by statistical methods. Table 6 is useful
`for estimating the probabilities of exceeding various peak
`values, given the rms value.
`Table 6. Estimation of Peak-to-Peak Noise
`% of Time That Noise Exceeds
`Nominal Peak-to-Peak Value
`32
`4.6
`0.27
`0.006
`
`Peak-to-Peak Value
`2 × rms
`4 × rms
`6 × rms
`8 × rms
`
`
`Rev. 0 | Page 12 of 16
`
`IPR2020-01192
`Apple EX1031 Page 12
`
`

`

`ADXL320
`
`USE AS A DUAL-AXIS TILT SENSOR
`Tilt measurement is one of the ADXL320’s most popular
`applications. 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, when it 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 of tilt, and resolution declines.
`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 both a roll axis and 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.
`
`
`
`
`Peak-to-peak noise values give the best estimate of the
`uncertainty in a single measurement. Table 7 gives the typical
`noise output of the ADXL320 for various CX and CY values.
`Table 7. Filter Capacitor Selection (CX, CY)
`Bandwidth
`CX, CY
`RMS Noise
`Peak-to-Peak Noise
`(Hz)
`(μF)
`(mg)
`Estimate (mg)
`10
`0.47
`1.0
`6
`50
`0.1
`2.25
`13.5
`100
`0.047
`3.2
`18.9
`500
`0.01
`7.1
`42.8
`USE WITH OPERATING VOLTAGES OTHER THAN 3 V
`The ADXL320 is tested and specified at VS = 3 V; however, it
`can be powered with VS as low as 2.4 V or as high as 5.25 V.
`Note that some performance parameters change as the supply
`voltage is varied.
`
`The ADXL320 output is ratiometric, so the output sensitivity
`(or scale factor) varies proportionally to supply voltage. At VS =
`5 V, the output sensitivity is typically 312 mV/g. At VS = 2.4 V,
`the output sensitivity is typically 135 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 = 5 V, the noise
`density is typically 150 μg/√Hz, while at VS = 2.4 V, the noise
`density is typically 300 μg/√Hz,
`
`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, the self-test response in volts
`is roughly proportional to the cube of the supply voltage. For
`example, at VS = 5 V, the self-test response for the ADXL320 is
`approximately 250 mV. At VS = 2.4 V, the self-test response is
`approximately 25 mV.
`
`The supply current decreases as the supply voltage decreases.
`Typical current consumption at VS = 5 V is 750 μA, and typical
`current consumption at VS = 2.4 V is 350 μA.
`
`
`
`
`
`Rev. 0 | Page 13 of 16
`
`IPR2020-01192
`Apple EX1031 Page 13
`
`

`

`ADXL320
`
`
`
`OUTLINE DIMENSIONS
`
`
`PIN 1
`INDICATOR
`
`TOP
`VIEW
`
`0.20 MIN
`
`4.15
`4.00 SQ
`3.85
`
`0.65 BSC
`
`0.55
`0.50
`0.45
`
`0.20 MIN
`
`12
`
`9
`
`13
`
`16
`
`BOTTOM
`VIEW
`
`8
`
`5
`
`1
`
`4
`
`PIN 1
`INDICATOR
`
`2.43
`1.75 SQ
`1.08
`
`1.95 BSC
`
`1.50
`1.45
`1.40
`
`SEATING
`PLANE
`
`0.05 MAX
`0.02 NOM
`COPLANARITY
`0.05
`
`0.35
`0.30
`0.25
`
`
`
`072606-A
`
`*STACKED DIE WITH GLASS SEAL.
`
`Figure 21. 16-Lead Lead Frame Chip Scale Package [LFCSP_LQ]
`4 mm × 4 mm Body
`(CP-16-5a*)
`Dimensions shown in millimeters
`
`
`
`ORDERING GUIDE
`
`Model
`ADXL320JCP1
`ADXL320JCP–REEL1
`ADXL320JCP–REEL71
`ADXL320EB
`
`
`Measurement
`Range
`±5 g
`±5 g
`±5 g
`
`
`Specified
`Voltage (V)
`3
`3
`3
`
`
`Temperature
`Range
`−20°C to +70°C
`−20°C to +70°C
`−20°C to +70°C
`
`
`Package Description
`16-Lead LFCSP_LQ
`16-Lead LFCSP_LQ
`16-Lead LFCSP_LQ
`Evaluation Board
`
`Package
`Option
`CP-16-5a
`CP-16-5a
`CP-16-5a
`
`
`
`1 Lead finish—Matte tin.
`
`
`Rev. 0 | Page 14 of 16
`
`IPR2020-01192
`Apple EX1031 Page 14
`
`

`

`
`
`
`
`NOTES
`
`
`
`
`
`
`
`
`ADXL320
`
`Rev. 0 | Page 15 of 16
`
`IPR2020-01192
`Apple EX1031 Page 15
`
`

`

`ADXL320
`
`
`
`NOTES
`
`
`
`
`
`
`
`
`
`
`© 2007 Analog Devices, Inc. All rights reserved. Trademarks and
`registered trademarks are the property of their respective owners.
`
`D04993–0–6/07(0)
`
`Rev. 0 | Page 16 of 16
`
`IPR2020-01192
`Apple EX1031 Page 16
`
`