ADXL325BCPZ-RL

ADXL325 AD | Alldatasheet

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Small, Low Power, 3-Axis ±5 g Accelerometer ADXL325 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. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 ©2009 Analog Devices, Inc. All rights reserved.

FEATURES

Small, low profile package 4 mm × 4 mm × 1.45 mm LFCSP Low power: 350 μA typical Single-supply operation: 1.8 V to 3.6 V 10,000 g shock survival Excellent temperature stability Bandwidth adjustment with a single capacitor per axis RoHS/WEEE lead-free compliant

APPLICATIONS

Cost-sensitive, low power, motion- and tilt-sensing applications Mobile devices Gaming systems Disk drive protection Image stabilization Sports and health devices GENERAL DESCRIPTION The ADXL325 is a small, low power, complete 3-axis accelerometer with signal conditioned voltage outputs. The product measures acceleration with a minimum full-scale range of ±5 g. It can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration, resulting from motion, shock, or vibration. The user selects the bandwidth of the accelerometer using the C X, CY, and CZ capacitors at the XOUT, YOUT, and ZOUT pins. Bandwidths can be selected to suit the application with a range of 0.5 Hz to 1600 Hz for X and Y axes and a range of 0.5 Hz to 550 Hz for the Z axis. The ADXL325 is available in a small, low profile, 4 mm × 4 mm × 1.45 mm, 16-lead, plastic lead frame chip scale package (LFCSP_LQ). FUNCTIONAL BLOCK DIAGRAM 3-AXIS SENSOR AC AMP DEMOD OUTPUT AMP OUTPUT AMP VS COM ST XOUT YOUT +3V CX CY ADXL325 CDC OUTPUT AMP ZOUT CZ ~32kΩ ~32kΩ ~32kΩ 07946-001 Figure 1.

Rev. 0 | Page 2 of 16 TABLE OF CONTENTS Design Trade-Offs for Selecting Filter Characteristics: The

REVISION HISTORY

8/09—Revision 0: Initial Version

Rev. 0 | Page 3 of 16 SPECIFICATIONS TA = 25°C, VS = 3 V , CX = CY = CZ = 0.1 μF, acceleration = 0 g, unless otherwise noted. All minimum and maximum specifications are guaranteed. Typical specifications are not guaranteed. Table 1. Parameter Conditions Min Typ Max Unit SENSOR INPUT Each axis Measurement Range ±5 ±6 g Nonlinearity Percent of full scale ±0.2 % Package Alignment Error ±1 Degrees Interaxis Alignment Error ±0.1 Degrees Cross-Axis Sensitivity1 ±1 % SENSITIVITY (RATIOMETRIC)2 Each axis Sensitivity at XOUT, YOUT, ZOUT V S = 3 V 156 174 192 mV/g Sensitivity Change Due to Temperature3 V S = 3 V ±0.01 %/°C ZERO g BIAS LEVEL (RATIOMETRIC) 0 g Voltage at XOUT, YOUT, ZOUT V S = 3 V 1.3 1.5 1.7 V 0 g Offset vs. Temperature ±1 mg/°C NOISE PERFORMANCE Noise Density XOUT, YOUT, ZOUT 250 μg/√Hz rms FREQUENCY RESPONSE4 Bandwidth XOUT, YOUT5 No external filter 1600 Hz Bandwidth ZOUT5 No external filter 550 Hz RFILT Tolerance 32 ± 15% kΩ Sensor Resonant Frequency 5.5 kHz SELF TEST6 Logic Input Low +0.6 V Logic Input High +2.4 V ST Actuation Current +60 μA Output Change at XOUT Self test 0 to 1 −90 −190 −350 mV Output Change at YOUT Self test 0 to 1 +90 +190 +350 mV Output Change at ZOUT Self test 0 to 1 +90 +320 +580 mV OUTPUT AMPLIFIER Output Swing Low No load 0.1 V Output Swing High No load 2.8 V POWER SUPPLY Operating Voltage Range 1.8 3.6 V Supply Current VS = 3 V 350 μA Turn-On Time7 No external filter 1 ms TEMPERATURE 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-to-maximum temperature or ambient-to-minimum temperature. 4 Actual frequency response controlled by user-supplied external filter capacitors (CX, CY, CZ). bandwidth = 0.5 Hz. 6 Self test response changes cubically with VS. 7 Turn-on time is dependent on CX, CY, CZ and is approximately 160 × CX or CY or CZ + 1 ms, where CX, CY, CZ are in μF.

Rev. 0 | Page 4 of 16 ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Rating Acceleration (Any Axis, Unpowered) 10,000 g Acceleration (Any Axis, Powered) 10,000 g VS −0.3 V to +3.6 V All Other Pins (COM − 0.3 V) to (VS + 0.3 V) Output Short-Circuit Duration (Any Pin to Common) Indefinite Temperature Range (Powered) −55°C to +125°C Temperature Range (Storage) −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

Figure 2. Pin Configuration Table 3. Pin Function Descriptions

1 NC No Connect (or Optionally Ground)

2 ST Self Test

3 COM Common

4 NC No Connect

5 COM Common

6 COM Common

7 COM Common

8 Z OUT Z Channel Output

9 NC No Connect (or Optionally Ground)

10 Y OUT Y Channel Output

11 NC No Connect

12 X OUT X Channel Output

13 NC No Connect

16 NC No Connect

EP Exposed pad Not internally connected. Solder for mechanical integrity.

Rev. 0 | Page 10 of 16 THEORY OF OPERATION The ADXL325 is a complete 3-axis acceleration measurement system. The ADXL325 has a measurement range of ±5 g minimum. 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 can measure the static acceleration of gravity in tilt-sensing applications, as well as dynamic acceleration, resulting from motion, shock, or vibration. 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 moving mass and unbalances the differential capacitor resulting in a sensor output whose amplitude is proportional to acceleration. Phase-sensitive demodulation techniques are then used to determine the magnitude and direction of the acceleration. The demodulator 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. MECHANICAL SENSOR The ADXL325 uses a single structure for sensing the X, Y , and Z axes. As a result, the three axes sense directions are highly orthogonal with little cross-axis sensitivity. Mechanical misalignment of the sensor die to the package is the chief source of cross-axis sensitivity. Mechanical misalignment can, of course, be calibrated out at the system level. PERFORMANCE Rather than using additional temperature compensation circuitry, innovative design techniques ensure that high performance is built-in to the ADXL325. As a result, there is neither quantization error nor nonmonotonic behavior, and temperature hysteresis is very low (typically <3 mg over the −25°C to +70°C temperature range).

similar effect as noise transmitted through VS. implement low-pass filtering for antialiasing and noise reduction. CY, and CZ is recommended in all cases. Table 4. Filter Capacitor Selection, CX, CY, and CZ VS, an electrostatic force is exerted on the accelerometer beam. diode between ST and VS is recommended. the measurement resolution (smallest detectable acceleration). analog filter bandwidth at XOUT, YOUT, and ZOUT. the analog-to-digital sampling frequency to minimize aliasing. the resolution and dynamic range of the accelerometer. Table 5. Estimation of Peak-to-Peak Noise performance parameters change as the supply voltage is varied. S = 3.6 V , the output sensitivity is typically 209 mV/g. At VS = 2 V , the output sensitivity is typically 116 mV/g. output is nominally equal to VS/2 at all supply voltages. noise density is typically 300 μg/√Hz.

0.65 BSC

1.081.95 BSC

0.20 MIN PIN 1

0.05 MAX

0.02 NOM

*STACKED DIE WITH GLASS SEAL. Figure 27. 16-Lead Lead Frame Chip Scale Package [LFCSP_LQ]

Rev. 0 | Page 15 of 16 NOTES

Rev. 0 | Page 16 of 16 NOTES Analog Devices offers specific products de signated for automotive applications; pleas e consult your local Analog Devices sales representative for details. Standard products sold by Analog Devices are not designed, intended, or approved for use in life support, implantable medi cal devices, transportation, nu clear, safety, or other equipment where malfunction of the product can reasonably be expected to result in personal injury, death, severe property damage, or severe environmental harm. Buyer uses or sells standard products for use in the above critical applications at Buye r's own risk and Buyer agrees to defend, indemnify, and hold harmless Analog Devices from any and all damages, claims, suits, or expenses resulting from such unintended use. ©2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the prop erty of their respective owners. D07946-0-8/09(0)