Small, Low Power, 3-Axis ±200 g Accelerometer Data Sheet ADXL377 FEATURES GENERAL DESCRIPTION 3-axis sensing The ADXL377 is a small, thin, low power, complete 3-axis Small, low profile package accelerometer with signal conditioned voltage outputs. The 3 mm × 3 mm × 1.45 mm LFCSP ADXL377 measures acceleration resulting from motion, shock, Low power: 300 µA (typical) or vibration with a typical full-scale range of ±200 g. Single-supply operation: 1.8 V to 3.6 V The user selects the bandwidth of the accelerometer using 10,000 g shock survival the C , C , and C capacitors at the X , Y , and Z pins. X Y Z OUT OUT OUT Excellent temperature stability Bandwidths can be selected to suit the application, with a range Bandwidth adjustment with a single capacitor per axis of 0.5 Hz to 1300 Hz for the x-axis and y-axis and a range of RoHS/WEEE and lead-free compliant 0.5 Hz to 1000 Hz for the z-axis. APPLICATIONS The ADXL377 is available in a small, low profile, 3 mm × 3 mm × Concussion and head trauma detection 1.45 mm, 16-lead lead frame chip scale package (LFCSP_LQ). High force event detection FUNCTIONAL BLOCK DIAGRAM +3V VS ADXL377 OUTPUT 32kΩ XOUT AC AMPLIFIERS AMPLIFIER CX CDC 32kΩ YOUT DEMODULATOR 3-AXIS CY SENSOR 32kΩ ZOUT CZ GND ST 10765-001 Figure 1. Rev. A Document Feedback 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. 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. Tel: 781.329.4700 ©2012–2018 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. Technical Support www.analog.com

ADXL377 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1  Performance ...................................................................................8  Applications ....................................................................................... 1  Applications Information .................................................................9  General Description ......................................................................... 1  Power Supply Decoupling ............................................................9  Functional Block Diagram .............................................................. 1  Setting the Bandwidth Using C , C , and C .............................9  X Y Z Revision History ............................................................................... 2  Self-Test ..........................................................................................9  Specifications ..................................................................................... 3  Selecting Filter Characteristics: Noise/Bandwidth Trade-Off ...... 9  Absolute Maximum Ratings ............................................................ 4  Axes of Acceleration Sensitivity ............................................... 10  ESD Caution .................................................................................. 4  Layout and Design Recommendations ................................... 11  Pin Configuration and Function Descriptions ............................. 5  Outline Dimensions ....................................................................... 12  Typical Performance Characteristics ............................................. 6  Ordering Guide .......................................................................... 12  Theory of Operation ........................................................................ 8  Mechanical Sensor ........................................................................ 8  REVISION HISTORY 9/2018—Rev. 0 to Rev. A Changes to Operating Temperature Range Parameter, Table 2 ....... 4 Updated Outline Dimensions ....................................................... 12 Changes to Ordering Guide .......................................................... 12 9/2012—Revision 0: Initial Version Rev. A | Page 2 of 12

Data Sheet ADXL377 SPECIFICATIONS T = 25°C, V = 3 V, C = C = C = 0.1 µF, acceleration = 0 g, unless otherwise noted. All minimum and maximum specifications are A S X Y Z guaranteed. Typical specifications are not guaranteed. Table 1. Parameter Test Conditions/Comments Min Typ Max Unit SENSOR INPUT Each axis Measurement Range ±200 g Nonlinearity % of full scale up to 180 g ±0.5 % Cross-Axis Sensitivity1 ±1.4 % SENSITIVITY, RATIOMETRIC2 Each axis Sensitivity at X , Y , and Z V = 3 V 5.8 6.5 7.2 mV/g OUT OUT OUT S Sensitivity Change Due to Temperature3 V = 3 V ±0.02 %/°C S ZERO g BIAS LEVEL, RATIOMETRIC Zero g Voltage V = 3 V, T = 25°C 1.4 1.5 1.6 V S A Zero g Offset vs. Temperature X-Axis and Y-Axis ±12 mg/°C Z-Axis ±30 mg/°C NOISE PERFORMANCE Noise Density X and Y 2.7 mg/√Hz OUT OUT Z 4.3 mg/√Hz OUT FREQUENCY RESPONSE4 Bandwidth5 No external filter X and Y 1300 Hz OUT OUT Z 1000 Hz OUT R Tolerance 32 ± 15% kΩ FILT Sensor Resonant Frequency 16.5 kHz SELF-TEST6 Logic Input Low 0.6 V Logic Input High 2.4 V ST Actuation Current 60 µA Output Change Self-test, 0 to 1 At X −6.5 mV OUT At Y 6.5 mV OUT At Z 11.5 mV OUT OUTPUT AMPLIFIER No load Output Swing Low 0.1 V Output Swing High 2.8 V POWER SUPPLY Operating Voltage Range7 1.8 3.0 3.6 V Supply Current V = 3 V 300 µA S Turn-On Time8 No external filter 1 ms OPERATING TEMPERATURE RANGE −40 +85 °C 1 Defined as coupling between any two axes. 2 Sensitivity is essentially ratiometric to VS. 3 Defined as the output change from ambient temperature to maximum temperature or from ambient temperature to minimum temperature. 4 Actual frequency response controlled by user-supplied external filter capacitors (CX, CY, and CZ). 5 Bandwidth with external capacitors = 1/(2π × 32 kΩ × Cx). 6 Self-test response changes cubically with VS. 7 Tested at 3.0 V and guaranteed by design only (not tested) to work over the full voltage range from 1.8 V to 3.6 V. 8 Turn-on time is dependent on CX, CY, and CZ and is approximately 160 × (CX or CY or CZ) + 1, where CX, CY, and CZ are in µF and the resulting turn-on time is in ms. Rev. A | Page 3 of 12

ADXL377 Data Sheet ABSOLUTE MAXIMUM RATINGS ESD CAUTION Table 2. Parameter Rating Acceleration (Any Axis) Unpowered 10,000 g Powered 10,000 g V −0.3 V to +3.6 V S All Other Pins (GND − 0.3 V) to (V + 0.3 V) S Output Short-Circuit Duration Indefinite (Any Pin to Ground) Operating Temperature Range −40°C to +85°C Storage Temperature Range −65°C to +150°C Stresses at or above those listed under Absolute Maximum Ratings may cause permanent damage to the product. This is a stress rating only; functional operation of the product at these or any other conditions above those indicated in the operational section of this specification is not implied. Operation beyond the maximum operating conditions for extended periods may affect product reliability. Rev. A | Page 4 of 12

Data Sheet ADXL377 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS OUT S S C Z V V N 16 15 14 13 ADXL377 RES 1 12 NC TOP VIEW ST 2 (Not to Scale) 11 NC +Y RES 3 +Z 10 NC YOUT 4 +X 9 NC 5 6 7 8 XOUT GND GND NC NOTES 1. NC = NO CONNECT. 2. THE EXPOSED PAD IS NOT INTERNALLY CFOORN NMEECCTHEADN, IBCUATL SINHTOEUGLRDI TBYE. SOLDERED 10765-002 Figure 2. Pin Configuration Table 3. Pin Function Descriptions Pin No. Mnemonic Description 1, 3 RES Reserved. This pin must be connected to GND or left open. 2 ST Self-Test. 4 Y Y Channel Output. OUT 5 X X Channel Output. OUT 6, 7 GND Must be connected to ground. 8 to 13 NC No Connect. Not internally connected. 14, 15 V Supply Voltage. 3.0 V typical. S 16 Z Z Channel Output. OUT EPAD Exposed Pad. The exposed pad is not internally connected, but should be soldered for mechanical integrity. Rev. A | Page 5 of 12

ADXL377 Data Sheet TYPICAL PERFORMANCE CHARACTERISTICS N > 250 for all typical performance figures, unless otherwise noted. N is the number of parts tested and used to produce the histograms. 35 1.525 1.520 30 %) 1.515 ON ( 25 V) ATI GE (1.510 OPUL 20 OLTA1.505 OF P 15 UT V1.500 T P EN UT1.495 C 10 O R E 1.490 P 5 1.485 0 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925OU1.4950TPU1.4975T V1.5000OL1.5025TAG1.5050E (V1.5075) 1.5100 1.5125 1.5150 1.5175 1.5200 10765-003 1.480–60 –40 –20 TE0MPERA20TURE (4°0C) 60 80 100 10765-006 Figure 3. X-Axis Zero g Output Voltage at 25°C, VS = 3 V Figure 6. X-Axis Zero g Offset vs. Temperature, VS = 3 V (14 Parts Soldered to PCB) 30 1.525 1.520 25 %) 1.515 ON ( V) ATI 20 GE (1.510 OF POPUL 15 UT VOLTA11..550005 T P EN 10 UT1.495 C O R E 1.490 P 5 1.485 0 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925OU1.4950TPU1.4975T V1.5000OL1.5025TAG1.5050E (V1.5075) 1.5100 1.5125 1.5150 1.5175 1.5200 10765-004 1.480–60 –40 –20 TE0MPERA20TURE (4°0C) 60 80 100 10765-007 Figure 4. Y-Axis Zero g Output Voltage at 25°C, VS = 3 V Figure 7. Y-Axis Zero g Offset vs. Temperature, VS = 3 V (14 Parts Soldered to PCB) 90 1.525 80 1.520 %) 70 1.515 ON ( V) OF POPULATI 654000 UT VOLTAGE (111...555001050 T P EN 30 UT1.495 C O R PE 20 1.490 10 1.485 0 1.4800 1.4825 1.4850 1.4875 1.4900 1.4925OU1.4950TPU1.4975T V1.5000OL1.5025TAG1.5050E (V1.5075) 1.5100 1.5125 1.5150 1.5175 1.5200 10765-005 1.480–60 –40 –20 TE0MPERA20TURE (4°0C) 60 80 100 10765-008 Figure 5. Z-Axis One g Output Voltage at 25°C, VS = 3 V Figure 8. Z-Axis Zero g Offset vs. Temperature, VS = 3 V (14 Parts Soldered to PCB) Rev. A | Page 6 of 12

Data Sheet ADXL377 25 250 %) 20 200 N ( O TI A PUL 15 T (g) 150 O U P P T OF 10 OUT 100 N E C R E P 5 50 X-AXIS Y-AXIS Z-AXIS 0 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35SE6.40NSI6.45TIV6.50ITY6.55 (m6.60V/6.65g)6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-009 00 5R0EFERENCE AC10C0ELERATION (1g5)0 200 10765-012 Figure 9. X-Axis Sensitivity at 25°C, VS = 3 V Figure 12. Typical Output Linearity over the Dynamic Range 30 10 25 %) N ( LATIO 20 mV/g) PU Y ( PO 15 VIT F TI O SI T N EN 10 SE C R E P 5 X-AXIS, Y-AXIS RESPONSE Z-AXIS RESPONSE 0 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35SE6.40NSI6.45TIV6.50ITY6.55 (m6.60V/6.65g)6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-010 110 100FREQUENCY (Hz)1k 10k 10765-013 Figure 10. Y-Axis Sensitivity at 25°C, VS = 3 V Figure 13. Typical Frequency Response 16 14 %) N ( 12 O TI A 10 L U P O 8 P F O T 6 N E C R 4 E P 2 0 6.00 6.05 6.10 6.15 6.20 6.25 6.30 6.35SE6.40NSI6.45TIV6.50ITY6.55 (m6.60V/6.65g)6.70 6.75 6.80 6.85 6.90 6.95 7.00 10765-011 Figure 11. Z-Axis Sensitivity at 25°C, VS = 3 V Rev. A | Page 7 of 12

ADXL377 Data Sheet THEORY OF OPERATION The ADXL377 is a complete 3-axis acceleration measurement The demodulator output is amplified and brought off chip through system with a typical measurement range of ±200 g. The ADXL377 a 32 kΩ resistor. The user then sets the signal bandwidth of the contains a polysilicon, surface-micromachined sensor and signal device by adding a capacitor. This filtering improves measurement conditioning circuitry to implement an open-loop acceleration resolution and helps prevent aliasing. measurement architecture. The output signals are analog voltages MECHANICAL SENSOR that are proportional to acceleration. The accelerometer can mea- The ADXL377 uses a single structure for sensing the accelera- sure the static acceleration of gravity in tilt-sensing applications, tion in the x-axis, y-axis, and z-axis. As a result, the three sense as well as dynamic acceleration resulting from motion, shock, directions are highly orthogonal with little cross-axis sensitivity. or vibration. Mechanical misalignment of the sensor die to the package or The sensor is a polysilicon, surface-micromachined structure misalignment of the package to the PCB is the chief source of built on top of a silicon wafer. Polysilicon springs suspend the cross-axis sensitivity. Mechanical misalignment can be calibrated structure over the surface of the wafer and provide resistance at the system level. against acceleration forces. Deflection of the structure is meas- PERFORMANCE ured using a differential capacitor that consists of independent fixed plates and plates attached to the moving mass. The fixed Rather than using additional temperature compensation circuitry, plates are driven by 180° out-of-phase square waves. Acceleration the ADXL377 uses innovative design techniques to ensure high deflects the moving mass and unbalances the differential capacitor, performance. As a result, there is neither quantization error nor resulting in a sensor output whose amplitude is proportional to nonmonotonic behavior, and temperature hysteresis is very low. acceleration. Phase-sensitive demodulation techniques are then used to determine the magnitude and direction of the acceleration. Rev. A | Page 8 of 12

Data Sheet ADXL377 APPLICATIONS INFORMATION POWER SUPPLY DECOUPLING Never expose the ST pin to voltages greater than V + 0.3 V. If S the system design is such that this condition cannot be guaran- For most applications, a single 0.1 µF capacitor, C , placed DC teed (for example, if multiple supply voltages are present), it is close to the ADXL377 supply pins adequately decouples the recommended that a clamping diode with low forward voltage accelerometer from noise on the power supply. However, in be connected between ST and V. applications where noise is present at the 50 kHz internal clock S frequency (or any harmonic thereof), additional care in power SELECTING FILTER CHARACTERISTICS: supply bypassing is required because this noise can cause errors NOISE/BANDWIDTH TRADE-OFF in acceleration measurement. The selected accelerometer bandwidth ultimately determines If additional decoupling is needed, a 100 Ω (or smaller) resistor the measurement resolution (smallest detectable acceleration). or ferrite bead can be inserted in the supply line. In addition, a Filtering can be used to lower the noise floor, thereby improving larger bulk bypass capacitor (1 µF or greater) can be added in the resolution of the accelerometer. Resolution is dependent on parallel to CDC. Ensure that the connection from the ADXL377 the analog filter bandwidth at XOUT, YOUT, and ZOUT. ground to the power supply ground is low impedance because The output of the ADXL377 has a typical bandwidth of 1000 Hz. noise transmitted through ground has a similar effect as noise The user must filter the signal at this point to limit aliasing errors. transmitted through V. S The analog bandwidth must be no more than half the analog-to- SETTING THE BANDWIDTH USING CX, CY, AND CZ digital sampling frequency to minimize aliasing. The analog bandwidth can be decreased further to reduce noise and The ADXL377 has provisions for band-limiting the X , Y , OUT OUT improve resolution. and Z pins. A capacitor must be added at each of these pins to OUT implement low-pass filtering for antialiasing and noise reduction. The ADXL377 noise has the characteristics of white Gaussian The equation for the −3 dB bandwidth is noise, which contributes equally at all frequencies and is described in terms of µg/√Hz (that is, the noise is proportional to the square f = 1/(2π × 32 kΩ × C) −3 dB x root of the accelerometer bandwidth). Limit the bandwidth to the or more simply, lowest frequency required by the application to maximize the f−3 dB = 5 µF/Cx resolution and dynamic range of the accelerometer. The tolerance of the internal resistor (RFILT) typically varies by as With the single-pole roll-off characteristic, the typical noise of much as ±15% of its nominal value (32 kΩ), and the bandwidth the ADXL377 is determined by varies accordingly. A minimum capacitance of 1000 pF for CX, rms Noise = Noise Density × ( BW×1.6) C , and C is recommended in all cases. Y Z It is often useful to know the peak value of the noise. Peak-to- Table 4. Filter Capacitor Selection for C , C , and C X Y Z peak noise can only be estimated by statistical methods. Table 5 Bandwidth (Hz) Capacitor (µF) can be used to estimate the probability of exceeding various peak 50 0.10 values, given the rms value. 100 0.05 200 0.025 Table 5. Estimation of Peak-to-Peak Noise 500 0.01 Percentage of Time That Noise Exceeds 1000 0.005 Peak-to-Peak Value Nominal Peak-to-Peak Value (%) SELF-TEST 2 × rms 32 4 × rms 4.6 The ST pin controls the self-test feature. When this pin is set to 6 × rms 0.27 V, an electrostatic force is exerted on the accelerometer beam. S 8 × rms 0.006 The resulting movement of the beam allows the user to test whether the accelerometer is functional. The typical change in output is −1.08 g (corresponding to −6.5 mV) for the x-axis, +1.08 g (or +6.5 mV) for the y-axis, and +1.83 g (or +11.5 mV) for the z-axis. The ST pin can be left open circuit or connected to ground (GND) in normal use. Rev. A | Page 9 of 12

ADXL377 Data Sheet AXES OF ACCELERATION SENSITIVITY Figure 14 shows the axes of sensitivity for the accelerometer. Figure 15 shows the output response when the accelerometer is oriented parallel to each of these axes. AZ AY AX 10765-014 Figure 14. Axes of Acceleration Sensitivity (Corresponding Output Voltage Increases When Accelerated Along the Sensitive Axis) XOUT = –1g YOUT = 0g ZOUT = 0g TOP GRAVITY XOUT = 0g XOUT = 0g YOUT = 1g TOP TOP YOUT = –1g ZOUT = 0g ZOUT = 0g TOP XOUT = 1g YOUT = 0g ZOUT = 0g XYZOOOUUUTTT === 100ggg XYZOOOUUUTTT === –001ggg 10765-015 Figure 15. Output Response vs. Orientation to Gravity Rev. A | Page 10 of 12

Data Sheet ADXL377 LAYOUT AND DESIGN RECOMMENDATIONS Figure 16 shows the recommended soldering profile; Table 6 describes the profile features. Figure 17 shows the recommended PCB layout or solder land drawing. CRITICAL ZONE TP tP TL TO TP RAMP-UP URETL TSMAX tL T A R PE TSMIN M E T PREtHSEAT RAMP-DOWN t25°C TIME 10765-016 Figure 16. Recommended Soldering Profile Table 6. Recommended Soldering Profile Profile Feature Sn63/Pb37 Pb-Free Average Ramp Rate (T to T) 3°C/sec max 3°C/sec max L P Preheat Minimum Temperature (T ) 100°C 150°C SMIN Maximum Temperature (T ) 150°C 200°C SMAX Time, T to T (t) 60 sec to 120 sec 60 sec to 180 sec SMIN SMAX S Ramp-Up Rate (T to T) 3°C/sec max 3°C/sec max SMAX L Time Maintained Above Liquidous (t) 60 sec to 150 sec 60 sec to 150 sec L Liquidous Temperature (T) 183°C 217°C L Peak Temperature (T) 240°C + 0°C/−5°C 260°C + 0°C/−5°C P Time Within 5°C of Actual Peak Temperature (t) 10 sec to 30 sec 20 sec to 40 sec P Ramp-Down Rate (T to T) 6°C/sec max 6°C/sec max P L Time 25°C to Peak Temperature (t ) 6 minutes max 8 minutes max 25°C 0.40 3 MAX 0.25 0.50 0.30 MAX 0.50 3 1.60 0.25 CENTER PAD IS NOT INTERNALLY CONNECTED BUT SHOULD BE SOLDERED FOR MECHANICAL INTEGRITY 1.60 DIMENSIONS SHOWN IN MILLIMETERS 10765-017 Figure 17. Recommended PCB Layout Rev. A | Page 11 of 12

ADXL377 Data Sheet OUTLINE DIMENSIONS DETAIL A 3.10 0.30 (JEDEC 95) 3.00 SQ 0.25 PIN 1 2.90 0.18 INDICATOR 0.50 13 16 (PINSINED EI1C DAETTAOIRL AAR)EA OPTIONS BSC 12 1 1.70 EXPPAODSED 1.60 SQ 1.50 9 4 0.45 8 5 0.20 MIN TOP VIEW 0.40 BOTTOM VIEW 1.50 0.35 FOR PROPER CONNECTION OF 1.45 SIDE VIEW THE EXPOSED PAD, REFER TO 1.40 THE PIN CONFIGURATION AND 0.05 MAX FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. 0.02 NOM COPLANARITY SEATING 0.08 PKG-003775 PLANE 0.152 REF 07-28-2017-A Figure 18. 16-Lead Lead Frame Chip Scale Package [LFCSP] 3 mm × 3 mm Body and 1.45 mm Package Height (CP-16-28) Dimensions shown in millimeters ORDERING GUIDE Measurement Specified Temperature Package Package Marking Model1 Range Voltage Range Description Option Code ADXL377BCPZ-RL ±200 g 3 V −40°C to +85°C 16-Lead LFCSP CP-16-28 Y4P ADXL377BCPZ-RL7 ±200 g 3 V −40°C to +85°C 16-Lead LFCSP CP-16-28 Y4P EVAL-ADXL377Z Evaluation Board 1 Z = RoHS Compliant Part. ©2012–2018 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10765-0-9/18(A) Rev. A | Page 12 of 12

Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: A nalog Devices Inc.: EVAL-ADXL377Z ADXL377BCPZ-RL7 ADXL377BCPZ-RL