SCA100T-D02-1

SCA100T Series Data Sheet THE SCA100T DUAL AXIS INCLINOMETER SERIES The SCA100T Series is a 3D-MEMS-based dual axis inclinometer family that provides instrumentation grade performance for leveling applications. The measuring axes of the sensing elements are parallel to the mounting plane and orthogonal to each other. Low temperature dependency, high resolution and low noise, together a with robust sensing element design, make the SCA100T the ideal choice for leveling instruments. The Murata inclinometers are unsensitive to vibration, due to their over damped sensing elements, and can withstand mechanical shocks of up to 20000 g. Features         Dual axis inclination measurement (X and Y) Measuring ranges ±30° SCA100T-D01 and ± 90° SCA100T-D02 0.0035° resolution (10 Hz BW, analog output) Sensing element controlled over damped frequency response (-3dB 18Hz) Robust design, high shock durability (20000g) High stability over temperature and time Single +5 V supply Ratiometric analog voltage outputs   Digital SPI inclination and temperature output Comprehensive failure detection features o True self test by deflecting the sensing elements’ proof mass by electrostatic force. o Continuous sensing element interconnection failure check. o Continuous memory parity check.  RoHS compliant  Compatible with Pb-free reflow solder process Applications     Platform leveling and stabilization 360° vertical orientation measurement Leveling instruments Construction levels 12 VDD Sensing element 1 Signal conditioning and filtering 11 OUT_1 A/D conversion 10 ST_1 Self test 1 9 ST_2 EEPROM calibration memory Self test 2 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. Murata Electronics Oy www.muratamems.fi Functional block diagram Subject to changes Doc.Nr. 8261800 1/17 Rev.B2 SCA100T Series TABLE OF CONTENTS The SCA100T Dual Axis Inclinometer Series .........................................................................1 Features............................................................................................................................................. 1 Applications ...................................................................................................................................... 1 Table of Contents......................................................................................................................2 1 Electrical Specifications .....................................................................................................3 1.1 Absolute Maximum Ratings ................................................................................................... 3 1.2 Performance Characteristics.................................................................................................. 3 1.3 Electrical Characteristics ....................................................................................................... 4 1.4 SPI Interface DC Characteristics............................................................................................ 4 1.5 SPI Interface AC Characteristics............................................................................................ 4 1.6 SPI Interface Timing Specifications ....................................................................................... 5 1.7 Electrical Connection.............................................................................................................. 6 1.8 Typical Performance Characteristics .................................................................................... 6 1.8.1 Additional External Compensation ...................................................................................... 7 2 Functional Description .......................................................................................................9 2.1 Measuring Directions .............................................................................................................. 9 2.2 Voltage to Angle Conversion ................................................................................................. 9 2.3 Ratiometric Output................................................................................................................ 10 2.4 SPI Serial Interface................................................................................................................ 10 2.5 Digital Output to Angle Conversion ..................................................................................... 12 2.6 Self Test and Failure Detection Modes ................................................................................ 13 2.7 Temperature Measurement .................................................................................................. 14 3 Application Information ....................................................................................................15 3.1 Recommended Circuit Diagrams and Printed Circuit Board Layouts ............................... 15 3.2 Recommended Printed Circuit Board Footprint ................................................................. 16 4 Mechanical Specifications and Reflow Soldering ..........................................................16 4.1 Mechanical Specifications (Reference only) ....................................................................... 16 4.2 Reflow Soldering ................................................................................................................... 17 Murata Electronics Oy www.muratamems.fi Subject to changes Doc. nr. 8261800 2/17 Rev.B2 SCA100T Series 1 Electrical Specifications The SCA100T product family comprises two versions, the SCA100T-D01 and the SCA100T-D02 that differ in measurement range. The product version specific performance specifications are listed in the table SCA100T performance characteristics below. All other specifications are common with both versions. 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 -0.3 V to +5.5V -0.3V to (VDD + 0.3V) -55°C to +125°C -40°C to +125°C Drop from 1 meter onto a concrete surface (20000g). Powered or non-powered ESD Protection: -Human Body Model -Charge Device Model Cleaning 1.2 ±2 kV ±500 V Ultrasonic cleaning not allowed Performance Characteristics Parameter Condition Measuring range Nominal Frequency response Offset (Output at 0g) Offset calibration error Offset Digital Output Sensitivity –3dB LP Ratiometric output (1 between 0…1° Sensitivity calibration error Sensitivity Digital Output Offset temperature dependency Sensitivity temperature dependency Typical non-linearity Digital output resolution (2 -25…85°C (typical) -40…125°C (max) -25...85°C (typical) -40…125°C (max) Measuring range (2 between 0…1° From DC...100Hz Output noise density Analog output resolution (4 Ratiometric error Cross-axis sensitivity Note 1. Note 2. Note 3. Note 4. Murata Electronics Oy www.muratamems.fi (4 (3 Bandwidth 10 Hz Vdd = 4.75...5.25V Max. SCA100T -D01 ±30 ±0.5 8-28 Vdd/2 ±0.11 1024 4 70 ±0.5 SCA100T -D02 ±90 ±1.0 8-28 Vdd/2 ±0.23 1024 2 35 ±0.5 Units 1638 ±0.008 ±0.86 ±0.014 -2.5...+1 ±0.11 11 0.035 0.0008 819 ±0.008 ±0.86 ±0.014 -2.5...+1 ±0.57 11 0.07 0.0008 LSB / g °/°C ° %/°C % ° Bits ° / LSB  / Hz 0.0035 ±2 4 0.0035 ±2 4 ° % % ° g Hz V ° LSB V/g mV/° % The frequency response is determined by the sensing element’s internal gas damping. The angle output has SIN curve relationship to voltage output 1st degree low pass filtered output Resolution = Noise density * √(bandwidth*1.6) Typical value for most of the components Subject to changes Doc. nr. 8261800 3/17 Rev.B2 SCA100T Series 1.3 Electrical Characteristics Parameter Supply voltage Vdd Current consumption Operating temperature Analog resistive output load Analog capacitive output load Start-up delay 1.4 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 kOhm 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 Tristate leakage VOL ILEAK Input terminal CSB Pull up current Input high voltage Input low voltage Hysteresis Input capacitance 1.5 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 for 8bit command and 11bit data @500kHz Murata Electronics Oy www.muratamems.fi @500kHz Subject to changes Doc. nr. 8261800 Min. Typ. 150 38 Max. Units 1 500 nF kHz s s 4/17 Rev.B2 SCA100T Series 1.6 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, RWTR: Time between conversion 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 Figure 2. Murata Electronics Oy www.muratamems.fi TSET DATA in LSB in TVAL2 MSB out TLZ DATA out LSB out Timing diagram for SPI communication Subject to changes Doc. nr. 8261800 5/17 Rev.B2 SCA100T Series 1.7 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. Inclination 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 1.8 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 limits (mean ± 3 standard deviation) and specification limits are presented in following diagrams. The 3 sigma limits represents 99.73% of the SCA100T population. Murata Electronics Oy www.muratamems.fi Subject to changes Doc. nr. 8261800 6/17 Rev.B2 SCA100T Series Temperature dependency of SCA100T offset 1 specification limit 0.8 offset error [degrees] 0.6 0.4 0.2 Average 0 +3 sigma -3 sigma -0.2 -0.4 -0.6 -0.8 specification limit -1 -40 -20 0 20 40 60 80 100 120 Temp [°C] Figure 4. Typical temperature dependency of SCA100T offset Temperature dependency of SCA100T sensitivity 1.00 specification limit sensitivity error [%] 0.50 0.00 Average -0.50 +3 sigma -1.00 -3 sigma -1.50 -2.00 -2.50 specification limit -40 -20 0 20 40 60 80 100 120 Temp [°C] Figure 5. Typical temperature dependency of SCA100T sensitivity 1.8.1 Additional External Compensation To achieve the best possible accuracy, the temperature measurement information and typical temperature dependency curves can be used for SCA100T offset and sensitivity temperature rd dependency compensation. The equation of fitted 3 order polynome curve for offset compensation is: Offcorr  0.0000006 *T 3  0.0001*T 2  0.0039 *T  0.0522 Where: Offcorr: T rd 3 order polynome fitted to average offset temperature dependency curve temperature in °C (Refer to paragraph 2.7 Temperature Measurement) The calculated compensation curve can be used to compensate the temperature dependency of the SCA100T offset by using following equation: OFFSETcomp  Offset  Offcorr Where: OFFSETcomp Offset Murata Electronics Oy www.muratamems.fi temperature compensated offset in degrees Nominal offset in degrees Subject to changes Doc. nr. 8261800 7/17 Rev.B2 SCA100T Series The equation of fitted 2 nd order polynome curve for sensitivity compensation is: Scorr  0.00011*T 2  0.0022 *T  0.0408 Where: Scorr: T nd 2 order polynome fitted to average sensitivity temperature dependency curve temperature in °C The calculated compensation curve can be used to compensate the temperature dependency of the SCA100T sensitivity by using following equation: SENScomp  SENS * (1  Scorr / 100) Where: SENScomp SENS temperature compensated sensitivity Nominal sensitivity (4V/g SCA100T-D01, 2V/g SCA100T-D02) The typical offset and sensitivity temperature dependency after external compensation is shown in the pictures below. Temperature dependency of externally compensated SCA100T offset 1 offset error [degrees] 0.8 0.6 0.4 0.2 Average 0 +3 sigma -3 sigma -0.2 -0.4 -0.6 -0.8 -1 -40 -20 0 20 40 60 80 100 120 Temp [°C] Figure 6. The temperature dependency of an externally compensated SCA100T offset Temperature dependency of externally compensated SCA100T sensitivity 1 0.8 sensitivity error [%] 0.6 0.4 0.2 Average 0 +3 sigma -3 sigma -0.2 -0.4 -0.6 -0.8 -1 -40 -20 0 20 40 60 80 100 120 Temp [°C] Figure 7. The temperature dependency of an externally compensated SCA100T sensitivity Murata Electronics Oy www.muratamems.fi Subject to changes Doc. nr. 8261800 8/17 Rev.B2 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 Voltage to Angle Conversion Analog output can be transferred to angle using the following equation for conversion:  Vout  Offset    Sensitivit y    arcsin  where: Offset = output of the device at 0° inclination position, Sensitivity is the sensitivity of the device and VDout is the output of the SCA100T. The nominal offset is 2.5 V and the sensitivity is 4 V/g for the SCA100T-D01 and 2 V/g for the SCA100T-D02. Angles close to 0° inclination can be estimated quite accurately with straight line conversion but for the best possible accuracy, arcsine conversion is recommended to be used. The following table shows the angle measurement error if straight line conversion is used. Straight line conversion equation:  Vout  Offset Sensitivit y Where: Sensitivity = 70mV/° with SCA100T-D01 or Sensitivity= 35mV/° with SCA100T-D02 Tilt angle [°] 0 1 2 3 4 5 10 15 30 Murata Electronics Oy www.muratamems.fi Straight line conversion error [°] 0 0.0027 0.0058 0.0094 0.0140 0.0198 0.0787 0.2185 1.668 Subject to changes Doc. nr. 8261800 9/17 Rev.B2 SCA100T Series 2.3 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. 2.4 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). 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) µP → SCA100T SCA100T → µP µP → SCA100T µP → 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:   Murata Electronics Oy www.muratamems.fi 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) Subject to changes Doc. nr. 8261800 10/17 Rev.B2 SCA100T Series   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 or RDAY is 5300 samples per sec for one channel at 500kHz clock maximum data transfer speed for RDAX and RDAY is 4150 samples per sec for two channel at 500kHz clock        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 µs. The load operation is disabled whenever the CSB signal is low, hence CSB must stay high at least 150 µs 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 10. Command and 8 bit temperature data transmission over the SPI Murata Electronics Oy www.muratamems.fi Subject to changes Doc. nr. 8261800 11/17 Rev.B2 SCA100T Series 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. 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 µs. The load operation is disabled whenever the CSB signal is low, hence CSB must stay high at least 150 µs 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. Recommended read cycle for X-,Y-channel and temperature: 1. Wait (150 µs) 2. RDAX (38 µs) 3. Wait (15 µs) 4. RDAY (38 µs) 5. Wait (15 µs) 6. RWTR (32 µs) 7. Goto 1. Figure 11. 2.5 Command and 11 bit acceleration data transmission over the SPI Digital Output to Angle Conversion The acceleration measurement results in RDAX and RDAY data registers are in 11 bit digital word format. The data range is from 0 to 2048. The nominal content of RDAX and RDAY data registers in zero angle position are: Binary: 100 0000 0000 Decimal: 1024 The transfer function from differential digital output to angle can be presented as Murata Electronics Oy www.muratamems.fi Subject to changes Doc. nr. 8261800 12/17 Rev.B2 SCA100T Series  Dout LSB   Dout@ 0 LSB    Sens LSB/g      arcsin  where; Dout Dout@0°  Sens digital output (RDAX or RDAY) digital offset value, nominal value = 1024 angle sensitivity of the device. (SCA100T-D01: 1638, SCA100T-D02: 819) As an example following table contains data register values and calculated differential digital output values with -5, -1 0, 1 and 5 degree tilt angles. 2.6 Angle [°] -5 Acceleration [mg] -87.16 -1 -17.45 0 0 1 17.45 5 87.16 RDAX (SCA100TD01) dec: 881 bin: 011 0111 0001 dec: 995 bin: 011 1110 0011 dec: 1024 bin: 100 0000 0000 dec: 1053 bin: 100 0001 1101 dec: 1167 bin: 100 1000 1111 RDAX (SCA100TD02) dec: 953 bin: 011 1011 1001 dec: 1010 bin: 011 1111 0010 dec: 1024 bin: 100 0000 0000 dec: 1038 bin: 100 0000 1110 dec: 1095 bin: 100 0100 0111 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 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 (