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Technical content
Features
- Sensitivity in two separate axes: 100g X-axis and 30g Y-axis
- Integral Signal Conditioning
- Linear Output
- Ratiometric Performance
- 4th Order Bessel Filter Preserves Pulse Shape Integrity
- Calibrated Self-test
- Low Voltage Detect, Clock Monitor, and EPROM Parity Check Status
- Transducer Hermetically Sealed at Wafer Level for Superior Reliability
- Robust Design, High Shocks Survivability
- Qualified AEC-Q100, Rev. F Grade 2 (-40 C/ +105C) Typical Applications
- Vibration Monitoring and Recording
- Impact Monitoring
- Appliance Control
- Mechanical Bearing Monitoring
- Computer Hard Drive Protection
- Computer Mouse and Joysticks
- Virtual Reality Input Devices
- Sports Diagnostic Devices and Systems
ORDERING INFORMATION
Device Temperature Range Case No. Package MMA3204EG –40 to +125°C 475A-02 SOIC-20 MMA3204EGR2 –40 to +125°C 475A-02 SOIC-20, Tape & Reel MMA3204KEG* –40 to +125°C 475A-02 SOIC-20 MMA3204KEGR2* –40 to +125°C 475A-02 SOIC-20, Tape & Reel *Part number sourced from a different facility. MMA3204KEG KEG SUFFIX (Pb-FREE) 20-LEAD SOIC CASE 475A-02 MMA3204KEG: XY-AXIS SENSITIVITY MICROMACHINED ACCELEROMETER ±100/30g Figure 1. Simplified Accelerometer Functional Block Diagram Figure 2. Pin Connections
2 Freescale Semiconductor, Inc. Table 1. Maximum Ratings
- Dropped onto concrete surface from any axis.
detrimental to its performance.
Table 2. Operating Characteristics
- For a loaded output the measurements are observed after an RC filter consisting of a 1 k resistor and a 0.01 F capacitor to ground.
- These limits define the range of operation fo r which the part will meet specification.
- Within the supply range of 4.75 and 5.25 volts, the device operates as a fully calibrated linear accelerometer. Beyond these supply limits
the device may operate as a linear device but is not guaranteed to be in calibration.
- The device can measure both + and – acceleration. With no input acceleration the output is at mid-supply. For positive acceleration the
output will increase above VDD/2 and for negative acceleration the output will decrease below VDD/2.
- The device is calibrated at 20g.
- At clock frequency 70 kHz.
- VOFF calculated with typical sensitivity.
- The digital input pin has an internal pull-down current source to prevent inadvertent self test initiation due to external board level leakages.
- Time for the output to reach 90% of its final value after a self-test is initiated.
- Time for amplifiers to recover after an ac celeration signal causing them to saturate.
- Preserves phase margin (60°) to guarantee output amplifier stability.
- A measure of the device's ability to reject an accele ration applied 90° from the true axis of sensitivity.
- The Status pin output is not valid following power-up until at least one rising edge has been applied to the self-test pin. The Status pin is
high whenever the self-test input is high, as a means to check the connectivity of the self-test and Status pins in the application.
- The Status pin output latches high if a Low Voltage Detection or Clock Frequency failure occurs, or the EPROM parity changes to odd. The
Status pin can be reset low if the self-test pin is pulsed with a high input for at least 100 s, unless a fault condition continues to exist.
0.44 VDD
0.50 VDD
0.56 VDD
Figure 3. SOIC Accelerometer with Recommended Figure 4. Recommended PCB Layout for Interfacing
- Use a 0.1 F capacitor on VDD to decouple the power source.
- Physical coupling distance of the accelerometer to the microcontroller should be minimal.
- Place a ground plane beneath the accelerometer to reduce noise, the ground plane should be attached to all of the open ended terminals shown in Figure 4.
- Use an RC filter of 1 k and 0.01 F on the output of the accelerometer to minimize clock noise (from the switched capacitor filter circuit).
- PCB layout of power and ground should not couple power supply noise.
- Accelerometer and microcontroller should not be a high current path.
- A/D sampling rate and any external power supply switching frequency should be selected such that they do not interfere with the internal accelerometer sampling frequency. This will prevent aliasing errors. Pin No. Pin Name Description 1 thru 3 — Leave unconnected. 4 — No internal connection. Leave unconnected.
5 ST Logic input pin used to initiate
7 STATUS Logic output pin to indicate
8V SS The power supply ground. 9V DD The power supply input. 10 AV DD Power supply input (Analog).
11 Y OUT Output voltage of the
6 Freescale Semiconductor, Inc. N/C N/C N/C ST XOUT STATUS VDD GND N/C N/C N/C N/C N/C N/C N/C V SS AVDD N/C YOUT N/C Direction of Earth’s gravity field.* * When positioned as shown, the Earth’s gravity will result in a positive 1g output in the X channel. Front View Side View Top View Static Acceleration Sensing Direction Dynamic Acceleration Sensing Direction Acceleration of the package in the X and Y direction (center plates move in the X and Y direction) will result in an increase in the X and Y outputs. 20-Pin SOIC Package N/C pins are recommended to be left FLOATING 11 12 13 14 15 16 17 18 19 20 10 9 8 7 6 5 4 3 2 1 Activation of Self test moves the center plates in the X and Y direction, resulting in an increase in the X and Y outputs.
shorting between solder pads. Figure 5. Footprint SOIC-20 (Case 475A-02)
8 Freescale Semiconductor, Inc. PACKAGE DIMENSIONS PAGE 1 OF 2 CASE 475A-02 ISSUE C 20-LEAD SOIC
Freescale Semiconductor, Inc. 9 MMA3204KEG
Table 4. Revision History
Rev. 1 How to Reach Us: Home Page: freescale.com Web Support: freescale.com/support Information in this document is provided solely to enable system and software implementers to use Freescale products. There are no express or implied copyright licenses granted hereunder to design or fabricate any integrated circuits based on the information in this document. Freescale reserves the right to make changes without further notice to any products herein. Freescale makes no warranty, representation, or guarantee regarding the suitability of its products for any particular purpose, nor does Freescale assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation consequential or incidental damages. “Typical” parameters that may be provided in Freescale data sheets and/or specifications can and do vary in different applications, and actual performance may vary over time. All operating parameters, including “typicals,” must be validated for each customer application by customer’s technical experts. Freescale does not convey any license under its patent rights nor the rights of others. Freescale sells products pursuant to standard terms and conditions of sale, which can be found at the following address: freescale.com/salestermsandconditions. Freescale, the Freescale logo, Energy Efficient Solutions logo, are trademarks of Freescale Semiconductor, Inc. All other product or service names are the property of their respective owners. © 2012 Freescale Semiconductor, Inc.