Freescale Semiconductor Technical Data MMA7260Q Rev 1 06 2005 MMA7260Q 1 5g 6g Three Axis Low g Micromachined Accelerometer The MMA7260Q low cost capacitive micromachined accelerometer features signal conditioning a 1 pole low pass filter temperature compensation and g Select which allows for the selection among 4 sensitivities Zero g offset full scale span and filter cut off are factory set and require no external devices Includes a Sleep Mode that makes it ideal for handheld battery powered electronics MMA7260Q XYZ AXIS ACCELEROMETER 1 5g 2g 4g 6g Features Selectable Sensitivity 1 5g 2g 4g 6g Low Current Consumption 500 A Sleep Mode 3 A Low Voltage Operation 2 2 V 3 6 V 6mm x 6mm x 1 45mm QFN High Sensitivity 800 mV g 1 5 g Fast Turn On Time High Sensitivity 1 5 g Integral Signal Conditioning with Low Pass Filter Robust Design High Shocks Survivability Pb Free Terminations Environmentally Preferred Package Low Cost Bottom View 16 LEAD QFN CASE 1622 01 Typical Applications Device Name Temperture Range Case No Package MMA7260Q 20 to 85 C 1622 01 QFN 16 Tube MMA7260QR2 20 to 85 C 1622 01 QFN 16 Tape Reel Freescale Semiconductor Inc 2005 All rights reserved XOUT YOUT ZOUT 16 15 14 13 12 Sleep Mode g Select2 2 11 N C VDD 3 10 N C VSS 4 9 N C 5 6 7 8 N C 1 N C g Select1 N C ORDERING INFORMATION Top View N C HDD MP3 Player Freefall Detection Laptop PC Freefall Detection Anti Theft Cell Phone Image Stability Text Scroll Motion Dialing E Compass Pedometer Motion Sensing PDA Text Scroll Navigation and Dead Reckoning E Compass Tilt Compensation Gaming Tilt and Motion Sensing Event Recorder Robotics Motion Sensing N C Figure 1 Pin Connections VDD g Select1 g Select2 G Cell Sensor Sleep Mode Oscillator Clock Generator X Temp Comp XOUT C to V Converter Gain Filter Y Temp Comp YOUT Z Temp Comp ZOUT Control Logic EEPROM Trim Circuits VSS Figure 2 Simplified Accelerometer Functional Block Diagram Table 1 Maximum Ratings Maximum ratings are the limits to which the device can be exposed without causing permanent damage Rating Symbol Value Unit Maximum Acceleration all axis gmax 2000 g Supply Voltage VDD 0 3 to 3 6 V Drop Test 1 Ddrop 1 8 m Tstg 40 to 125 C Storage Temperature Range 1 Dropped onto concrete surface from any axis ELECTRO STATIC DISCHARGE ESD WARNING This device is sensitive to electrostatic discharge Although the Freescale accelerometer contains internal 2000 V ESD protection circuitry extra precaution must be taken by the user to protect the chip from ESD A charge of over 2000 volts can accumulate on the human body or associated test equipment A charge of this magnitude can alter the performance or cause failure of the chip When handling the accelerometer proper ESD precautions should be followed to avoid exposing the device to discharges which may be detrimental to its performance MMA7260Q 2 Sensors Freescale Semiconductor Table 2 Operating Characteristics Unless otherwise noted 20 C TA 85 C 2 2 V VDD 3 6 V Acceleration 0g Loaded output 1 Characteristic Symbol Min Typ Max Unit Supply Voltage 3 VDD 2 2 3 3 3 6 V Supply Current IDD 500 800 A Operating Range 2 Supply Current at Sleep Mode 4 IDD 3 10 A TA 20 85 C g Select1 2 00 gFS 1 5 g g Select1 2 10 gFS 2 0 g g Select1 2 01 gFS 4 0 g g Select1 2 11 gFS 6 0 g Operating Temperature Range Acceleration Range X Axis Y Axis Z Axis Output Signal Zero g TA 25 C VDD 3 3 V 5 Zero g VOFF 1 485 1 65 1 815 V VOFF TA 2 mg C Sensitivity TA 25 C VDD 3 3 V S1 5g 740 800 860 mV g 2g S2g 555 600 645 mV g 4g S4g 277 5 300 322 5 mV g 6g S6g 185 200 215 mV g S TA 0 03 C XY f 3dB 350 Hz Z f 3dB 150 Hz nRMS 4 7 mVrms nPSD 350 g Hz tRESPONSE 1 0 2 0 ms tENABLE 0 5 2 0 ms XY fGCELL 6 0 kHz Z fGCELL 3 4 kHz fCLK 11 kHz VFSO VSS 0 25 VDD 0 25 V NLOUT 1 0 1 0 FSO VXY XZ YZ 5 0 1 5g Sensitivity Bandwidth Response Noise RMS 0 1 Hz 1 kHz 4 Power Spectral Density RMS 0 1 Hz 1 kHz 4 Control Timing Power Up Response Time 6 Enable Response Time 7 Sensing Element Resonant Frequency Internal Sampling Frequency Output Stage Performance Full Scale Output Range IOUT 30 A Nonlinearity XOUT YOUT ZOUT Cross Axis Sensitivity 8 1 For a loaded output the measurements are observed after an RC filter consisting of a 1 0 k resistor and a 0 1 F capacitor to ground 2 These limits define the range of operation for which the part will meet specification 3 Within the supply range of 2 2 and 3 6 V 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 4 This value is measured with g Select in 1 5g mode 5 The device can measure both and acceleration With no input acceleration the output is at midsupply For positive acceleration the output will increase above VDD 2 For negative acceleration the output will decrease below VDD 2 6 The response time between 10 of full scale Vdd input voltage and 90 of the final operating output voltage 7 The response time between 10 of full scale Sleep Mode input voltage and 90 of the final operating output voltage 8 A measure of the device s ability to reject an acceleration applied 90 from the true axis of sensitivity MMA7260Q Sensors Freescale Semiconductor 3 PRINCIPLE OF OPERATION The Freescale accelerometer is a surface micromachined integrated circuit accelerometer The device consists of two surface micromachined capacitive sensing cells g cell and a signal conditioning ASIC contained in a single integrated circuit package The sensing elements are sealed hermetically at the wafer level using a bulk micromachined cap wafer The g cell is a mechanical structure formed from semiconductor materials polysilicon using semiconductor processes masking and etching It can be modeled as a set of beams attached to a movable central mass that move between fixed beams The movable beams can be deflected from their rest position by subjecting the system to an acceleration Figure 3 As the beams attached to the central mass move the distance from them to the fixed beams on one side will increase by the same amount that the distance to the fixed beams on the other side decreases The change in distance is a measure of acceleration The g cell beams form two back to back capacitors Figure 3 As the center beam moves with acceleration the distance between the beams changes and each capacitor s value will change C A D Where A is the area of the beam …
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