Low Cost ±1.5 g Tri Axis Accelerometer with Ratiometric Outputs MXR9500G/M FEATURES Low cost RoHS compliant Resolution better than 1 milli-g Tri-axis accelerometer in a single package. On chip mixed signal processing No moving parts No loose particle issues >50,000 g shock survival rating SMT package: 7mm X 7mm X 1.8mm 2.7V to 3.6V single supply continuous operation No adjusting external components needed X Sensor Gain Adjust Temp Comp A/D D/A LPF Xout Y Sensor Gain Adjust Temp Comp A/D D/A LPF Yout Z Sensor Gain Adjust Temp Comp A/D D/A LPF Zout VSA1 Reference Digital Interface Clock VSA2 APPLICATIONS GPS – Electronic Compass Tilt Correction/Navigation Consumer – LCD projectors, pedometers, blood pressure Monitor, digital cameras/MP3 players Information Appliances – Computer Peripherals/PDA’s/Mouse Smart Pens/Cell Phones Gaming – Joystick/RF Interface/Menu Selection/Tilt Sensing Security – Gas Line/Elevator/Fatigue Sensing GENERAL DESCRIPTION The MXR9500G/M is a low cost, tri axis accelerometer fabricated on a standard, submicron CMOS process. It is a complete sensing system with on-chip mixed signal processing. The MXR9500G/M measures acceleration with a full-scale range of ±1.5 g and a sensitivity of 500mV/g @3.0V at 25°C. It can measure both dynamic acceleration (e.g. vibration) and static acceleration (e.g. gravity). The MXR9500G/M design is based on heat convection and requires no solid proof mass. This eliminates stiction and particle problems associated with competitive devices and provides shock survival greater than 50,000 g, leading to significantly lower failure rate and lower loss due to handling during PCB assembly and at customer field application. Information furnished by MEMSIC is believed to be accurate and reliable. However, no responsibility is assumed by MEMSIC for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of MEMSIC. MEMSIC MXR9500G/M Preliminary Page 1 of 5 VDD1 VDD2 VDD3 DI1 SCK1 DI2 SCK2 FUNCTIONAL BLOCK DIAGRAM The MXR9500G/M provides three ratiometric analog outputs that are set to 50% of the power supply voltage at zero g. The Max. noise floor is 1 mg/ Hz allowing signals below 1 milli-g to be resolved at 1 Hz bandwidth. The MXR9500G/M is packaged in a hermetically sealed, surface mount LCC 16pins package (7 mm x 7 mm x 1.8 mm height) and is operational over a -40°C to +85°C (M) and 0°C to +70°C (G) temperature range. I2C fast mode interface is soon available in the next generation chip. ©MEMSIC, Inc. 800 Turnpike St., Suite 202, North Andover, MA 01845 Tel: 978.738.0900 Fax: 978.738.0196 www.memsic.com 8/26/2005 MXR9500G/M SPECIFICATIONS (Measurements @ 25°C, Acceleration = 0 g unless otherwise noted; VDD1,VDD3 = 3.0V unless otherwise specified) Parameter 1 Measurement Range Nonlinearity Alignment Error2 Transverse Sensitivity3 Sensitivity Sensitivity Change Over Temperature Zero g Offset Bias Level Zero g Offset TC Normal Output Range Noise Density, RMS Conditions Min Each Axis Best fit straight line X, Y-axis Z-axis ±1.5 475 ∆ from 25°C 1.45 -0.1 ∆ from 25°C, based on 500mV/g X,Y-axis Z-axis Output High Output Low X,Y-axis Z-axis Resolution Frequency Response Output Drive Capability Turn-On Time4 Operating Voltage Range Supply Current Power Down Current Operating Temperature Range Max 0.5 ± 1.0 ± 3.0 ± 2.0 500 15 1.50 0.0 1.0 1.55 +0.1 0.2 mg/°C mg/°C V V 525 2.8 0.6 0.9 0.5 17 mg/ Hz 1 100 2.7 0 -40 75 3.0 4.2 Units g % of FS degrees degrees % mV/g % V g 1.0 1.5 @1Hz BW @-3dB @2.7V-3.6V MXR9500G MXR9500M Typ 3.6 0.1 +70 +85 mg/ Hz mg Hz µA mS V mA uA °C °C NOTES 1 Guaranteed by measurement of initial offset and sensitivity. 2 Alignment error is specified as the angle between the true and indicated axis of sensitivity. 3 Cross axis sensitivity is the algebraic sum of the alignment and the inherent sensitivity errors. 4 Output settled to within ±17mg. MEMSIC MXR9500G/M Preliminary Page 2 of 5 8/26/2005 ABSOLUTE MAXIMUM RATINGS* ………………...-0.5 to +7.0V Supply Voltage (VDD) Storage Temperature ……….…………-65°C to +150°C Acceleration ……………………………………..50,000 g *Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; the functional operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Pin Description: LCC-16 Package Pin Name Description 1 NC Do Not Connect 2 Zout Z Channel Output 3 VSA2 Connect to Ground 4 VDD1 2.7V to 3.6V 5 DI1 Power Down Pin 6 SCK1 Connect to Ground 7 NC Do Not Connect 8 VSA1 Connect to Ground 9 NC Do Not Connect 10 NC Do Not Connect 11 VDD2 2.7V to 3.6V 12 Yout Y Channel Output 13 Xout X Channel Output 14 VDD3 2.7V to 3.6V 15 SCK2 Connect to Ground 16 DI2 Power Down Pin 6 5 4 3 2 7 +X 1 8 +Y 9 +Z 16 10 15 11 12 13 14 (Top View) +X +Z (Side View) Ordering Guide Model Temperature Range Package MXR9500GZ 0 to 70°C LCC16, RoHS compliant MXR9500MZ -40 to 85°C LCC16, RoHS compliant All parts are shipped in tape and reel packaging. Caution: ESD (electrostatic discharge) sensitive device. MEMSIC MXR9500G/M Preliminary Page 3 of 5 8/26/2005 THEORY OF OPERATION The MEMSIC device is a complete tri-axis acceleration measurement system in a single package fabricated on CMOS IC process. The device operation is based on heat transfer by natural convection and operates like other accelerometers having a proof mass except it is a gas in MEMSIC sensor. Xout – This pin is the analog output of the X-axis acceleration sensor. Yout – This pin is the analog output of the Y-axis acceleration sensor Zout – This pin is the analog output of the Z-axis Heat source, centered in the silicon chip is suspended across a cavity. Equally spaced aluminum/polysilicon thermopiles (groups of thermocouples) are located equidistantly on all four sides of the heat source. Under zero acceleration, a temperature gradient is symmetrical about the heat source, so that the temperature is the same at all four thermopiles, causing them to output the same voltage. Acceleration in any direction will disturb the temperature profile, due to free convection heat transfer, causing it to be asymmetrical. The temperature, and hence voltage output of the four thermopiles will then be different. The differential voltage at the thermopile outputs is directly proportional to the acceleration. Please visit the MEMSIC website at www.memsic.com for a picture/graphic description of the free convection heat transfer principle. acceleration sensor. POWER SUPPLY NOISE REJECTION One capacitor is recommended for best rejection of power supply noise. The capacitor should be located as close as possible to the device supply pin (VDD1,VDD3). The capacitor lead length should be as short as possible, and surface mount capacitor is preferred. For typical applications, the capacitor can be ceramic 0.1 µF. Power Supply VDD1 VDD3 MXR9500G/M PIN DESCRIPTIONS VDD1, VDD2, VDD3– These pins are the supply input for the circuits and the sensor heater in the accelerometer. The DC voltage should be between 2.7 and 3.6 volts. Refer to the section on PCB layout and fabrication suggestions for guidance on external parts and connections recommended. VSA1, VSA2– These pins are ground pin for the accelerometer. MEMSIC Accelerometer PCB LAYOUT AND FABRICATION SUGGESTIONS 1. SCK1, SCK2– These pins are for factory used only, should be connect to ground. 2. It is best to solder a 0.1uF capacitor directly across VDD1, VSA1 and VDD3, VSA2 pin. Robust low inductance ground wiring should be used. DI1, DI2– These pins are the power down control pin. Pull these pins HIGH will put the accelerometer into power down mode. When the part goes into power down mode, the total current will be smaller than 0.1uA at 3V. In normal operation mode, this pin should be connected to Ground. MEMSIC MXR9500G/M Preliminary Page 4 of 5 8/26/2005 PACKAGE DRAWING 0.5x45 MEMSIC MXR9500G/M Preliminary Page 5 of 5 8/26/2005