Doc.Nr. 82 1178 00 Data Sheet SCA100T-D07 2-AXIS HIGH PERFORMANCE ANALOG ACCELEROMETER Features Applications Measurement range 12g Measurement bandwidth 400 Hz Low noise ratiometric analog voltage outputs Excellent bias stability over temperature and time Digital SPI temperature output Comprehensive failure detection features o True self test by deflecting the sensing element's proof mass with electrostatic force. o Continuous sensing element interconnection failure check. o Continuous memory parity check. RoHS and lead free soldering process compliant Robust design, high shock durability (20000g) SCA100T-D07 is targeted to inertial sensing applications with high stability and tough environmental requirements. Typical application include IMU, AHRS Avionics UAV Navigation and guidance instruments Platform stabilization Vibration monitoring Oil & Gas surveying and drilling Train and Rail industry General Description The SCA100T-D07 is a 3D-MEMS-based dual axis accelerometer that enables tactical grade performance for Inertial Measurement Units (IMUs) operating in tough environmental conditions. The measuring axes of the sensor are parallel to the mounting plane and orthogonal to each other. Wide measurement range and bandwidth, low repeatable temperature behavior, low output noise, together with a very robust sensing element and packaging design, make the SCA100T-D07 the ideal choice for challenging inertial sensing applications. 12 VDD Sensing element 1 Signal conditioning and filtering 11 OUT_1 A/D conversion 10 ST_1 9 ST_2 Self test 1 Self test 2 EEPROM calibration memory Temperature Sensor 1 SCK SPI interface 3 MISO 4 MOSI 7 CSB Sensing element 2 Signal conditioning and filtering 5 OUT_2 6 GND Figure 1. Functional block diagram Murata Electronics Oy www.muratamems.fi Subject to changes Doc.Nr. 82 1178 00 1/16 Rev.A2 SCA100T Series TABLE OF CONTENTS 1 Electrical Specifications .....................................................................................................3 1.1 Absolute Maximum Ratings ................................................................................................... 3 1.2 Performance Characteristics.................................................................................................. 3 1.3 Parameter ................................................................................................................................ 3 1.4 Electrical Characteristics ....................................................................................................... 4 1.5 SPI Interface DC Characteristics............................................................................................ 4 1.6 SPI Interface AC Characteristics............................................................................................ 4 1.7 SPI Interface Timing Specifications ....................................................................................... 5 1.8 Electrical Connection.............................................................................................................. 6 1.9 Typical Performance Characteristics .................................................................................... 6 2 Functional Description .......................................................................................................9 2.1 Measuring Directions .............................................................................................................. 9 2.2 Ratiometric Output.................................................................................................................. 9 2.3 SPI Serial Interface.................................................................................................................. 9 2.4 Self Test and Failure Detection Modes ................................................................................ 12 2.5 Temperature Measurement .................................................................................................. 13 3 Application Information ....................................................................................................14 3.1 Recommended Circuit Diagrams and Printed Circuit Board Layouts ............................... 14 3.2 Recommended Printed Circuit Board Footprint ................................................................. 15 4 Mechanical Specifications and Reflow Soldering ..........................................................15 4.1 Mechanical Specifications (Reference only) ....................................................................... 15 4.2 Reflow Soldering ................................................................................................................... 16 Murata Electronics Oy Subject to changes 2/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 1 Electrical Specifications The product version specific performance specifications are listed in the table SCA100T performance characteristics below. Vdd=5.00V and ambient temperature unless otherwise specified. 1.1 Absolute Maximum Ratings Supply voltage (VDD) Voltage at input / output pins Storage temperature Operating temperature Mechanical shock 1.2 -0.3 V to +5.5V -0.3V to (VDD + 0.3V) -55C to +125C -40C to +125C Drop from 1 meter onto a concrete surface (20000g). Powered or non-powered Performance Characteristics 1.3 Parameter Measuring range Frequency response Offset (Output at 0g) Offset Digital Output Offset Calibration error Offset Temperature Dependency Offset Temperature Hysteresis Sensitivity Sensitivity Digital Output Sensitivity Calibration error Sensitivity Temperature Dependency Linearity error Condition Min Typical Max (1 Units Nominal -3dB LP Ratiometric output -12 250 Vdd/2 400 +12 550 Vdd/2 -25...+85C -40...+125C -40...+125C -45 -200 -300 -50 g Hz V LSB mg mg mg mg 1024 45 200 300 50 0.17 70 -25...+85C -40...+125C -15...+85C +25C Digital Output Resolution Output Noise Density From DC...100Hz Ratiometric error Cross-axis sensitivity Vdd = 4.75...5.25V Max. Note 1. (1 -2 -2 -2.5 -60 -25 11 95 -2 -3.5 V/g LSB / g % % % mg mg Bits +2 +2 +2.5 60 25 11 120 g / Hz +2 +3.5 % % Min/Max values are +/-3 sigma of test population Murata Electronics Oy Subject to changes 3/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 1.4 Electrical Characteristics Parameter Supply voltage Vdd Current consumption Operating temperature Analog resistive output load Analog capacitive output load Start-up delay 1.5 Min. Typ Max. Units 4.75 5.0 4 5.25 5 V mA +125 C Vdd = 5 V; No load -40 Vout to Vdd or GND 10 k Vout to Vdd or GND 20 nF Reset and parity check 10 ms SPI Interface DC Characteristics Parameter Conditions Symbol Min Typ. Max Unit VIN = 0 V IPU VIH VIL VHYST CIN 13 4 -0.3 22 35 Vdd+0.3 1 A V V V pF Input terminal MOSI, SCK Pull down current VIN = 5 V Input high voltage Input low voltage Hysteresis IPD VIH VIL VHYST 9 4 -0.3 29 Vdd+0.3 1 0.23*Vdd A V V V Input capacitance CIN 2 pF Output terminal MISO Output high voltage I > -1mA VOH Output low voltage Tri-state leakage VOL ILEAK Input terminal CSB Pull up current Input high voltage Input low voltage Hysteresis Input capacitance 1.6 Condition I < 1 mA 0 < VMISO < Vdd 0.23*Vdd 2 17 Vdd0.5 V 5 0.5 100 V pA SPI Interface AC Characteristics Parameter Condition Output load SPI clock frequency Internal A/D conversion time Data transfer time @500kHz @500kHz Min. Typ. 150 38 Max. Units 1 500 nF kHz s s Murata Electronics Oy Subject to changes 4/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 1.7 SPI Interface Timing Specifications Parameter Terminal CSB, SCK Time from CSB (10%) To SCK (90%) Time from SCK (10%) To CSB (90%) Terminal SCK SCK low time Conditions Symbol Min. TLS1 120 ns TLS2 120 ns TCL 1 s TCH 1 s TSET 30 ns THOL 30 ns Load capacitance at MISO < 15 pF Load capacitance at MISO < 15 pF TVAL1 10 100 ns TLZ 10 100 ns Load capacitance at MISO < 15 pF TVAL2 100 ns Load capacitance at MISO < 2 nF Load capacitance at MISO < 2 nF SCK high time Terminal MOSI, SCK Time from changing MOSI (10%, 90%) to SCK (90%). Data setup time Time from SCK (90%) to changing MOSI (10%,90%). Data hold time Terminal MISO, CSB Time from CSB (10%) to stable MISO (10%, 90%). Time from CSB (90%) to high impedance state of MISO. Terminal MISO, SCK Time from SCK (10%) to stable MISO (10%, 90%). Terminal CSB Time between SPI cycles, CSB at high level (90%) When using SPI commands RDAX, RDAY, and RWTR: Time between SPI cycles, CSB at high level (90%) TLS1 TCH Typ. Max. Unit TLH 15 s TLH 150 s TCL TLS2 TLH CSB SCK THOL MOSI MSB in TVAL1 MISO TSET DATA in LSB in TVAL2 MSB out TLZ DATA out LSB out Figure 2. Timing diagram for SPI communication Murata Electronics Oy Subject to changes 5/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 1.8 Electrical Connection If the SPI interface is not used SCK (pin1), MISO (pin3), MOSI (pin4) and CSB (pin7) must be left floating. Self-test can be activated applying logic "1" (positive supply voltage level) to ST_1 or ST_2 pins (pins 10 or 9). Self-test must not be activated for both channels at the same time. If ST feature is not used pins 9 and 10 must be left floating or connected to GND. Acceleration signals are provided from pins OUT_1 and OUT_2. SCK SCK 1 VDD 12 VDD OUT_1 11 OUT_1 Ext_C_1 2 MISO 3 MISO 10 ST_1/Test_in ST_1 MOSI 4 MOSI 9 ST_2 ST_2 OUT_2 5 OUT_2 8 Ext_C_2 VSS 6 GND 7 CSB CSB Figure 3. SCA100T electrical connection No. 1 2 3 4 5 6 7 8 9 10 11 12 1.9 Node SCK NC MISO MOSI Out_2 GND CSB NC ST_2 ST_1 Out_1 VDD I/O Input Input Output Input Output Supply Input Input Input Input Output Supply Description Serial clock No connect, left floating Master in slave out; data output Master out slave in; data input Y axis Output (Ch 2) Ground Chip select (active low) No connect, left floating Self test input for Ch 2 Self test input for Ch 1 X axis Output (Ch 1) Positive supply voltage (+5V DC) Typical Performance Characteristics Typical offset and sensitivity temperature dependencies of the SCA100T are presented in following diagrams. These results represent the typical performance of SCA100T components. The mean value and 3 sigma limit (mean 3x standard deviation) and specification limits are presented in following diagrams. The 3 sigma limits represents 99.73% of the SCA100T population. Murata Electronics Oy Subject to changes 6/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series SCA100T-D07 Offset Temperature Dependency 300 Offset error [mg] 200 100 -3 sigma 0 Average -100 +3 sigma -200 -300 -400 -40 -20 0 20 40 60 80 100 120 Temperature [C] Figure 4. Typical temperature behavior of SCA100T-D07 offset SCA100T-D07 Sensitivity Errors Over Temperature 3.00 % Sensitivity Error[%] 2.00 % 1.00 % 0.00 % Average +3 sigma -1.00 % -3 sigma -2.00 % -3.00 % -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature[C] Figure 5. Typical temperature behavior of SCA100T-D07 sensitivity Murata Electronics Oy Subject to changes 7/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series Frequency response 0 -3 Attenuation[dB] -6 -9 -12 -15 -18 -21 -24 -27 -30 10 100 1000 10000 Frequency[Hz] Figure 6. Frequency response of SCA100T-D07 Error[mg] Typical SCA100T-D07 Non-Linearity of X-axis in 25C 25 20 15 10 5 0 -5 -10 -15 -20 -25 -12 -9 -6 -3 0 3 6 9 12 Acceleration[g] Figure 7. Typical non-linearity of SCA100T-D07 fitted to straight line in room temperature Murata Electronics Oy Subject to changes 8/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 2 2.1 Functional Description Measuring Directions X-axis Y-axis VOUT > VOUT =2.5V > VOUT Figure 8. The measuring directions of the SCA100T 2.2 Ratiometric Output Ratiometric output means that the zero offset point and sensitivity of the sensor are proportional to the supply voltage. If the SCA100T supply voltage is fluctuating the SCA100T output will also vary. When the same reference voltage for both the SCA100T sensor and the measuring part (A/Dconverter) is used, the error caused by reference voltage variation is automatically compensated for. 2.3 SPI Serial Interface A Serial Peripheral Interface (SPI) system consists of one master device and one or more slave devices. The master is defined as a micro controller providing the SPI clock and the slave as any integrated circuit receiving the SPI clock from the master. The ASIC in Murata Electronics' products always operates as a slave device in master-slave operation mode. The SPI has a 4-wire synchronous serial interface. Data communication is enabled by a low active Slave Select or Chip Select wire (CSB). Data is transmitted by a 3-wire interface consisting of wires for serial data input (MOSI), serial data output (MISO) and serial clock (SCK). Murata Electronics Oy Subject to changes 9/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series MASTER MICROCONTROLLER SLAVE DATA OUT (MOSI) SI DATA IN (MISO) SO SERIAL CLOCK (SCK) SCK SS0 CS SS1 SI SS2 SO SS3 SCK CS SI SO SCK CS SI SO SCK CS Figure 9. Typical SPI connection The SPI interface in Murata products is designed to support any micro controller that uses SPI bus. Communication can be carried out by either a software or hardware based SPI. Please note that in the case of hardware based SPI, the received acceleration data is 11 bits. The data transfer uses the following 4-wire interface: MOSI MISO SCK CSB master out slave in master in slave out serial clock chip select (low active) P SCA100T SCA100T P P SCA100T P SCA100T Each transmission starts with a falling edge of CSB and ends with the rising edge. During transmission, commands and data are controlled by SCK and CSB according to the following rules: commands and data are shifted; MSB first, LSB last each output data/status bits are shifted out on the falling edge of SCK (MISO line) each bit is sampled on the rising edge of SCK (MOSI line) after the device is selected with the falling edge of CSB, an 8-bit command is received. The command defines the operations to be performed the rising edge of CSB ends all data transfer and resets internal counter and command register if an invalid command is received, no data is shifted into the chip and the MISO remains in high impedance state until the falling edge of CSB. This reinitializes the serial communication. data transfer to MOSI continues immediately after receiving the command in all cases where data is to be written to SCA100T's internal registers data transfer out from MISO starts with the falling edge of SCK immediately after the last bit of the SPI command is sampled in on the rising edge of SCK maximum SPI clock frequency is 500kHz maximum data transfer speed for RDAX and RDAY is 5300 samples per sec / channel Murata Electronics Oy Subject to changes 10/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series SPI command can be either an individual command or a combination of command and data. In the case of combined command and data, the input data follows uninterruptedly the SPI command and the output data is shifted out parallel with the input data. The SPI interface uses an 8-bit instruction (or command) register. The list of commands is given in Table below. Command name MEAS RWTR STX STY RDAX RDAY Command format 00000000 00001000 00001110 00001111 00010000 00010001 Description: Measure mode (normal operation mode after power on) Read temperature data register Activate Self test for X-channel Activate Self test for Y-channel Read X-channel acceleration Read Y-channel acceleration Measure mode (MEAS) is standard operation mode after power-up. During normal operation, the MEAS command is the exit command from Self test. Read temperature data register (RWTR) reads temperature data register during normal operation without affecting the operation. The temperature data register is updated every 150 s. The load operation is disabled whenever the CSB signal is low, hence CSB must stay high at least 150 s prior to the RWTR command in order to guarantee correct data. The data transfer is presented in Figure 10 below. The data is transferred MSB first. In normal operation, it does not matter what data is written into temperature data register during the RWTR command and hence writing all zeros is recommended. Figure 1. Command and 8 bit temperature data transmission over the SPI Self test for X-channel (STX) activates the self test function for the X-channel (Channel 1). The internal charge pump is activated and a high voltage is applied to the X-channel acceleration sensor element electrode. This causes the electrostatic force that deflects the beam of the sensing element and simulates the acceleration to the positive direction. The self-test is de-activated by giving the MEAS command. The self test function must not be activated for both channels at the same time. Self test for Y-channel (STY) activates the self test function for the Y-channel (Channel 2). The internal charge pump is activated and a high voltage is applied to the Y-channel acceleration sensor element electrode. Read X-channel acceleration (RDAX) accesses the AD converted X-channel (Channel 1) acceleration signal stored in acceleration data register X. Murata Electronics Oy Subject to changes 11/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series Read Y-channel acceleration (RDAY) accesses the AD converted Y-channel (Channel 2) acceleration signal stored in acceleration data register Y. During normal operation, acceleration data registers are reloaded every 150 s. The load operation is disabled whenever the CSB signal is low, hence CSB must stay high at least 150 s prior the RDAX command in order to guarantee correct data. Data output is an 11-bit digital word that is fed out MSB first and LSB last. Figure 10. Command and 11 bit acceleration data transmission over the SPI 2.4 Self Test and Failure Detection Modes To ensure reliable measurement results the SCA100T has continuous interconnection failure and calibration memory validity detection. A detected failure forces the output signal close to power supply ground or VDD level, outside the normal output range. The normal output ranges are: analog 0.25-4.75 V (@Vdd=5V) and SPI 102...1945 counts. The calibration memory validity is verified by continuously running parity check for the control register memory content. In the case where a parity error is detected, the control register is automatically re-loaded from the EEPROM. If a new parity error is detected after re-loading data both analog output voltages are forced to go close to ground level (<0.25 V) and SPI outputs go below 102 counts. The SCA100T also includes a separate self test mode. The true self test simulates acceleration, or deceleration, using an electrostatic force. The electrostatic force simulates acceleration that is high enough to deflect the proof mass to the extreme positive position, and this causes the output signal to go to the maximum value. The self test function is activated either by a separate on-off command on the self test input, or through the SPI. The self-test generates an electrostatic force, deflecting the sensing element's proof mass, thus checking the complete signal path. The true self test performs following checks: Sensing element movement check ASIC signal path check PCB signal path check Micro controller A/D and signal path check The created deflection can be seen in both the SPI and analogue output. The self test function is activated digitally by a STX or STY command, and de-activated by a MEAS command. Self test can be also activated applying logic"1" (positive supply voltage level) to ST pins (pins 9 & 10) of Murata Electronics Oy Subject to changes 12/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series SCA100T. The self test Input high voltage level is 4 - Vdd+0.3 V and input low voltage level is 0.3 - 1 V. The self test function must not be activated for both channels at the same time. ST pin voltage 5V 0V 5V V1 Vout V2 V3 T3 T2 T1 0V T4 T5 Figure 11. Self test wave forms V1 = initial output voltage before the self test function is activated. V2 = output voltage during the self test function. V3 = output voltage after the self test function has been de-activated and after stabilization time Please note that the error band specified for V3 is to guarantee that the output is within 5% of the initial value after the specified stabilization time. After a longer time (max. 1 second) V1=V3. T1 = Pulse length for Self test activation T2 = Saturation delay T3 = Recovery time T4 = Stabilization time =T2+T3 T5 = Rise time during self test. Self test characteristics: T1 [ms] T2 [ms] T3 [ms] 20-100 Typ. 25 Typ. 30 2.5 T4 [ms] Typ. 55 T5 [ms] Typ. 15 V2: Min 0.95*VDD (4.75V @Vdd=5V) V3: 0.95*V1-1.05*V1 Temperature Measurement The SCA100T has an internal temperature sensor, which is used for internal offset compensation. The temperature information is also available for additional external compensation. The temperature sensor can be accessed via the SPI interface and the temperature reading is an 8-bit word (0...255). The transfer function is expressed with the following formula: T Counts 197 1.083 Where: Counts T Temperature reading Temperature in C The temperature measurement output is not calibrated. The internal temperature compensation routine uses relative results where absolute accuracy is not needed. If the temperature Murata Electronics Oy Subject to changes 13/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series measurement results are used for additional external compensation then one point calibration in the system level is needed to remove the offset. With external one point calibration the accuracy of the temperature measurement is about 1 C. 3 3.1 Application Information Recommended Circuit Diagrams and Printed Circuit Board Layouts The SCA100T should be powered from a well regulated 5 V DC power supply. Coupling of digital noise to the power supply line should be minimized. 100nF filtering capacitor between VDD pin 12 and GND plane must be used. The SCA100T has a ratiometric output. To get the best performance use the same reference voltage for both the SCA100T and Analog/Digital converter. Use low pass RC filters with 5.11 k and 10nF on the SCA100T outputs to minimize clock noise. Locate the 100nF power supply filtering capacitor close to VDD pin 12. Use as short a trace length as possible. Connect the other end of capacitor directly to the ground plane. Connect the GND pin 6 to underlying ground plane. Use as wide ground and power supply planes as possible. Avoid narrow power supply or GND connection strips on PCB. Figure 12. Analog connection and layout example Figure 13. SPI connection example Murata Electronics Oy Subject to changes 14/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 3.2 Recommended Printed Circuit Board Footprint Figure 14. Recommended PCB footprint 4 4.1 Mechanical Specifications and Reflow Soldering Mechanical Specifications (Reference only) Lead frame material: Plating: Solderability: RoHS compliance: Co-planarity error: Part weight: Copper Nickel followed by Gold JEDEC standard: JESD22-B102-C RoHS compliant lead free component. 0.1mm max. <1.2 g Figure 15. Mechanical dimensions of the SCA100T (Dimensions in mm) Murata Electronics Oy Subject to changes 15/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2 SCA100T Series 4.2 Reflow Soldering The SCA100T is suitable for Sn-Pb eutectic and Pb- free soldering process and mounting with normal SMD pick-and-place equipment. Figure 16. Recommended SCA100T body temperature profile during reflow soldering. Ref. IPC/JEDEC J-STD-020B. Profile feature Sn-Pb Eutectic Assembly Average ramp-up rate (TL to TP) Pb-free Assembly 3C/second max. 3C/second max. 150C Preheat - Temperature min (Tsmin) 100C - Temperature max (Tsmax) 150C 200C - Time (min to max) (ts) 60-120 seconds 60-180 seconds Tsmax to T, Ramp up rate 3C/second max Time maintained above: - Temperature (TL) - Time (tL) Peak temperature (TP) Time within 5C of actual Peak Temperature (TP) Ramp-down rate Time 25 to Peak temperature 183C 217C 60-150 seconds 60-150 seconds 240 +0/-5C 250 +0/-5C 10-30 seconds 20-40 seconds 6C/second max 6C/second max 6 minutes max 8 minutes max The Moisture Sensitivity Level of the part is 3 according to the IPC/JEDEC J-STD-020B. The part should be delivered in a dry pack. The manufacturing floor time (out of bag) in the customer's end is 168 hours. Notes: Preheating time and temperatures according to guidance from solder paste manufacturer. It is important that the part is parallel to the PCB plane and that there is no angular alignment error from intended measuring direction during assembly process. Wave soldering is not recommended. Ultrasonic cleaning is not allowed. The sensing element may be damaged by an ultrasonic cleaning process. Murata Electronics Oy Subject to changes 16/16 www.muratamems.fi Doc. nr. 82 1178 00 Rev.A2