View SCA103T_1305805.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

SCA103T Series
Data Sheet
THE SCA103T DIFFERENTIAL INCLINOMETER SERIES
The SCA103T Series is a 3D-MEMS-based single axis inclinometer family that uses the differential measurement principle. The high calibration accuracy combines extremely low temperature dependency, high resolution and low noise together with a robust sensing element design, to make the SCA103T an ideal choice for high accuracy leveling instruments. The VTI inclinometers are insensitive to vibration due to having over damped sensing elements plus they can withstand mechanical shocks of 20000 g.
Features
* * * * * * * Measuring ranges 15 SCA103T-D04 and 30 SCA103T-D05 0.001 resolution (10 Hz BW, analog output) Sensing element controlled over damped frequency response (-3dB 18Hz) Robust design, high shock durability (20000g) Excellent stability over temperature and time Common mode error and noise reduction using the differential measurement principle 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 Rotating laser levels * * Leveling instruments Construction levels
12 VDD
Sensing element 1
Signal conditioning and filtering A/D conversion
11 OUT_1
10 ST_1
Self test 1
9 ST_2
Self test 2
EEPROM calibration memory
Temperature Sensor SPI interface
1 SCK 3 MISO 4 MOSI 7 CSB
Sensing element 2
Signal conditioning and filtering
5 OUT_2
6 GND
Figure 1.
Functional block diagram
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
1/19 Rev.A
SCA103T Series
TABLE OF CONTENTS
The SCA103T Differential Inclinometer Series .......................................................................1
Features................................................................................................................................................1 Applications .........................................................................................................................................1
Table of Contents .....................................................................................................................2 1 Electrical Specifications .....................................................................................................3
1.1 1.2 1.3 1.4 1.5 1.6 1.7 Absolute Maximum Ratings......................................................................................................3 Performance Characteristics ....................................................................................................3 Electrical Characteristics ..........................................................................................................4 SPI Interface DC Characteristics ..............................................................................................4 SPI Interface AC Characteristics ..............................................................................................4 SPI Interface Timing Specifications .........................................................................................5 Electrical Connection ................................................................................................................6
1.8 Typical Performance Characteristics.......................................................................................6 1.8.1 Additional External Compensation ........................................................................................7
2 Functional Description .......................................................................................................9
2.1 2.2 2.3 2.4 2.5 2.6 2.7 Differential Measurement ..........................................................................................................9 Voltage to Angle Conversion....................................................................................................9 Ratiometric Output ..................................................................................................................10 SPI Serial Interface ..................................................................................................................10 Digital Output to Angle Conversion .......................................................................................13 Self Test and Failure Detection Modes ..................................................................................14 Temperature Measurement .....................................................................................................15
3 Application Information ....................................................................................................16
3.1 3.2 Recommended Circuit Diagrams and Printed Circuit Board Layouts ................................16 Recommended Printed Circuit Board Footprint ...................................................................17
4 Mechanical Specifications and Reflow Soldering ..........................................................17
4.1 4.2 Mechanical Specifications (Reference only) .........................................................................17 Reflow Soldering......................................................................................................................18
5 Document Change Control...............................................................................................19 6 Contact Information ..........................................................................................................19
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
2/19 Rev.A
SCA103T Series
1
Electrical Specifications
The SCA103T product family consists of two versions, the SCA103T-D04 and the SCA103T-D05, that differ in measurement range. The specific performance specifications related to each version are listed in the table "SCA103T performance characteristics" below. All other specifications are common to both versions. The supply voltage is Vdd=5.00V and ambient temperature unless otherwise specified. Parameters marked as D are valid when measured in differential mode using an external differential amplifier. Parameters marked with S are for a single measurement channel. The performance of the selected amplifier may have an effect on some parameters. The differential signal is determined as Out_diff = Out1 - Out2.
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) -55C to +125C -40C to +125C Drop from 1 metre onto a concrete surface (20000g). Powered or non-powered
1.2
Performance Characteristics
Parameter Measuring range Frequency response Offset (Output at 0g) Offset calibration error Offset Digital Output Sensitivity Sensitivity calibration error Sensitivity Digital Output Offset temperature dependency Sensitivity temperature dependency Typical non-linearity Digital output resolution Output noise density Analog output resolution Cross-axis sensitivity Ratiometric error Long term stability (4
Note 1. Note 2. Note 3. Note 4.
D/S D S S S S D S D D D D D D D S S D
Condition Nominal -3dB LP (1 Ratiometric output
between 0...1 (2
-25...85C (typical) -40...125C (max) -25...85C (typical) -40...125C (max) Measuring range between 0...1 (2 From DC...100Hz Bandwidth 10 Hz Max. Vdd = 4.75...5.25V
(3
SCA103T -D04 15 0.26 8-28 Vdd/2 0.057 1024 16 280 0.5 6554 0.002 0.29 0.013 -2.5...+1 0.057 12 0.009 0.0004 0.0013 4 1 <0.004
SCA103T -D05 30 0.5 8-28 Vdd/2 0.11 1024 8 140 0.5 3277 0.002 0.29 0.013 -2.5...+1 0.11 12 0.017 0.0004 0.0013 4 1 <0.004
Units g Hz V LSB V/g mV/ % LSB / g /C %/C % Bits / LSB
/ Hz
% %
The frequency response is determined by the sensing element's internal gas damping. The angle output has SIN curve relationship to voltage output - refer to chapter 2.2 Resolution = Noise density * (bandwidth) Power continuously connected (@ 23C)
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
3/19 Rev.A
SCA103T Series
1.3
Electrical Characteristics
Parameter Supply voltage Vdd Current consumption Operating temperature Analog resistive output load Analog capacitive output load Start-up delay Condition Vdd = 5 V; No load -40 Vout to Vdd or GND Vout to Vdd or GND Reset and parity check 10 20 10 Min. 4.75 Typ 5.0 4 Max. 5.25 5 +125 Units V mA C kOhm nF ms
1.4
SPI Interface DC Characteristics
Parameter Input terminal CSB Pull up current Input high voltage Input low voltage Hysteresis Input capacitance Conditions Symbol Min Typ Max Unit
VIN = 0 V
IPU VIH VIL VHYST CIN
13 4 -0.3
22 0.23*Vdd 2
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 Input capacitance Output terminal MISO Output high voltage I > -1mA Output low voltage Tristate leakage I < 1 mA 0 < VMISO < Vdd
IPD VIH VIL VHYST CIN
9 4 -0.3
17 0.23*Vdd 2
29 Vdd+0.3 1
A V V V pF
VOH VOL ILEAK
Vdd0.5 5 0.5 100
V V pA
1.5
SPI Interface AC Characteristics
Parameter
Output load SPI clock frequency Internal A/D conversion time Data transfer time
Condition
@500kHz
Min.
Typ.
150 38
Max.
1 500
Units
nF kHz s s
@500kHz
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
4/19 Rev.A
SCA103T 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 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 SPI cycles, CSB at high level (90%)
Conditions
Symbol TLS1 TLS2
Min. 120 120 1 1
Typ.
Max.
Unit ns ns s s
Load capacitance at MISO < 2 nF Load capacitance at MISO < 2 nF
TCL TCH
TSET THOL
30 30
ns ns
Load capacitance at MISO < 15 pF Load capacitance at MISO < 15 pF Load capacitance at MISO < 15 pF
TVAL1 TLZ
10 10
100 100
ns ns
TVAL2
100
ns
TLH TLH
15 150
s s
TLS1 CSB SCK
TCH
TCL
TLS2
TLH
THOL MOSI TVAL1 MISO
MSB out MSB in DATA in
TSET
LSB in
TVAL2
DATA out LSB out
TLZ
Figure 2.
Timing diagram for SPI communication
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
5/19 Rev.A
SCA103T 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 the 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 1 SCK VDD 12 VDD OUT_1 11 OUT_1
Ext_C_1 2 MISO MISO 3 MOSI MOSI 4 OUT_2 OUT_2 5 VSS GND 6
10 ST_1/Test_in ST_1 9 8 7 ST_2 ST_2 Ext_C_2 CSB CSB
Figure 3. No. 1 2 3 4 5 6 7 8 9 10 11 12
SCA103T electrical connection 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 Output 2 (Ch 2) Ground Chip select (active low) No connect, left floating Self test input for Ch 2 Self test input for Ch 1 Output 1(Ch 1) Positive supply voltage (+5V DC)
1.8
Typical Performance Characteristics
Typical offset and sensitivity temperature dependencies of SCA103T are presented in following diagrams. These results represent the typical performance of SCA103T components. The mean value and 3 sigma limits (mean 3x standard deviation) and specification limits are presented in following diagrams. The 3 sigma limits represents 99.73% of the SCA103T population.
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
6/19 Rev.A
SCA103T Series
temperature dependency of SCA103T offset (differential output)
0.3 specification limit
0.2 Differential offset error [degrees]
0.1 average +3 Sigma -3 Sigma -0.1
0
-0.2
-0.3 -40
specification limit -20 0 20 40 Tem p [C] 60 80 100 120
Figure 4.
Typical temperature dependency of SCA103T offset
Tem perature dependency of SCA103T sensitivity [%] (differential output) 1.5 1 Differential sensitivity error [%] 0.5 0 -0.5 -1 -1.5 -2 -2.5 -3 -40 specification limit -20 0 20 40 Tem p [C] 60 80 100 120 specification limit average +3 Sigma -3 Sigma
Figure 5.
Typical temperature dependency of SCA103T sensitivity
1.8.1
Additional External Compensation
To achieve the best possible accuracy, the temperature measurement information and typical temperature dependency curve can be used for SCA103T sensitivity temperature dependency compensation. The offset temperature dependency curves do not have any significant tendency so there is no need for any additional external compensation for offset. By using an additional 3rd order polynome compensation curve based on average sensitivity temperature dependency curve and temperature measurement information, it is possible to reduce sensitivity temperature dependency from 0.013%/C down to 0.005%/C. The equation for the fitted 3rd order polynome curve is:
Scorr = -0.0000005 * T 3 - 0.00005 * T 2 + 0.0032 * T - 0.031
Where: Scorr: T 3rd order polynome fitted to average sensitivity temperature dependency curve temperature in C (Refer to paragraph 2.7- Temperature Measurement)
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
7/19 Rev.A
SCA103T Series
The calculated compensation curve can be used to compensate for the temperature dependency of the SCA103T sensitivity by using following equation:
SENScomp = SENS * (1 + Scorr / 100)
Where: SENScomp SENS temperature compensated sensitivity Nominal sensitivity (16V/g SCA103T-D04, 8V/g SCA103T-D05)
The typical sensitivity temperature dependency after 3rd order compensation is shown in the figure below.
The temperature dependency of 3rd order compensated SCA103T sensitivity [%] (differential output)
1 0.8 0.6 Differential sensitivity error [%] 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 -40 compensated average +3 Sigma limit -3 Sigma limit
-20
0
20 Tem p [C]
40
60
80
Figure 6.
The temperature dependency of 3rd order compensated SCA103T sensitivity
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
8/19 Rev.A
SCA103T Series
2 2.1
Functional Description Differential Measurement
The measuring axis of SCA103T sensing elements are mutually opposite in direction, thus providing two inclination signals which can be differentiated externally, either by using a differential amplifier or a microcontroller. The differential measurement principle removes all common mode measurement errors. Most of the error sources have similar effects on both sensing elements. These errors are removed from measurement result during signal differentiation. The differential measurement principle gives very efficient noise reduction, improved long term stability and extremely low temperature dependency. Typical output characteristics (Channels 1, 2 and differential output: OUT1-OUT2) are presented in the figure below. For differential amplifier connection refer to the recommended circuit diagram.
SCA103T-D04 outputs and differential amplifier output
6.0 5.0 4.0 3.0 2.0 Output [V] 1.0 0.0 -1.0 -2.0 -3.0 -4.0 -5.0 -6.0 -20
D 1
SCA103T OUT_1 SCA103T OUT_2 Differential output
2
-15
-10
-5
0 Tilt angle [ ]
5
10
15
20
Figure 7.
Differential output characteristics
2.2
Voltage to Angle Conversion
The analog output behavior of the SCA103T is described in the figure below. The arrow represents the measuring axis direction marking on the top of SCA103T package.
Earth's gravity
OUT1 < OUT2 > DIFF < Figure 8.
OUT1 =2.5V OUT2 =2.5V DIFF =0 V
< OUT1 > OUT2 Behavior of the analog output
The analog output can be transferred to angle by using the following equation for conversion:
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
9/19 Rev.A
SCA103T Series
= arcsin
VDout - Offset Sensitivity
where Offset is the output of the device at 0 inclination position, Sensitivity is the sensitivity of the device and VDout is the output of differential amplifier. In the case of differential amplifier connection shown in the chapter Recommended circuit diagram the nominal offset output is 0 V and the sensitivity is 16 V/g with SCA103T-D04 and 8 V/g with SCA103T-D05. Angles close to 0 inclination can be estimated quite accurately with straight line conversion but for best possible accuracy arcsine conversion is recommended to be used. Following table shows the angle measurement error if straight line conversion is used. Straight line conversion equation:
=
VDout - Offset Sensitivity
Where: Sensitivity = 280mV/ with SCA103T-D04 or Sensitivity= 140mV/ with SCA103T-D05 Tilt angle [] 0 1 2 3 4 5 10 15 30 Straight line conversion error [] 0 0.0027 0.0058 0.0094 0.0140 0.0198 0.0787 0.2185 1.668
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 SCA103T supply voltage is fluctuating, the SCA103T output will also vary. When the same reference voltage for both the SCA103T sensor and the measuring part (A/Dconverter) is used, the error caused by reference voltage variation is automatically compensated.
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 microcontroller providing the SPI clock and the slave as any integrated circuit receiving the SPI clock from the master. The ASIC in VTI Technologies' 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 with 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).
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
10/19 Rev.A
SCA103T Series
MASTER MICROCONTROLLER
DATA OUT (MOSI) DATA IN (MISO) SERIAL CLOCK (SCK) SS0 SS1 SS2 SS3 SI SO SCK CS SI SO SCK CS SI SO SCK CS
SLAVE SI SO SCK CS
Figure 9.
Typical SPI connection
The SPI interface in VTI products is designed to support any micro controller that uses SPI bus. Communication can be carried out by 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 SCA103T SCA103T P P SCA103T P SCA103T
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 SCA103T'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
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 in 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.
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
11/19 Rev.A
SCA103T Series
Command name MEAS RWTR RDSR RLOAD STX STY RDAX RDAY
Command format 00000000 00001000 00001010 00001011 00001110 00001111 00010000 00010001
Description: Measure mode (normal operation mode after power on) Read and write temperature data register Read status register Reload NV data to memory output register Activate Self test for X-channel Activate Self test for Y-channel Read X-channel acceleration through SPI Read Y-channel acceleration through SPI
Measure mode (MEAS) is the standard operation mode after power-up. During normal operation, MEAS command is the exit command from Self test. Read temperature data register (RWTR) reads the temperature data register during normal operation without effecting the operation. 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.
C SB
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
SC K
C O M M AN D D A T A IN 7 6 5 4 3 2 1 0
M OSI
H IG H IM PED AN C E
D A TA O U T 7 6 5 4 3 2 1 0
M ISO
Figure 10.
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. 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 to 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.
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
12/19 Rev.A
SCA103T Series
CSB
0 1 2 3 4 5 6
7
8
9
10
11
12
13
14
15
16
17
18
SCK
COM M AND
M OSI
DATA OUT 10 9 8 7 6 5 4 3 2 1 0
H IG H IM P E D A N C E
M IS O
Figure 11.
Command and 11 bit acceleration data transmission over the SPI
2.5
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 To obtain the differential digital output value, Dout, RDAY must be subtracted from RDAX. Dout = RDAX - RDAY The transfer function from differential digital output to angle can be presented as
= arcsin
where; Dout
Dout [LSB] - Dout@ 0 [LSB] Sens [LSB/g]
differential digital output (RDAX - RDAY) digital offset value, nominal value = 0 in differential mode angle sensitivity of the device. (SCA103T-D04: 6554, SCA103T-D05: 3277)
Dout@0
Sens
As an example, the following table contains SCA103T-D04 data register values and calculated differential digital output values with -5, -1 0, 1 and 5 degree tilt angles.
Angle [] -5 -1 0 1 5
Acceleration RDAX [mg] -87.16 dec: 739 bin: 010 1110 0011 -17.45 dec: 967 bin: 011 1100 0111 0 dec: 1024 bin: 100 0000 0000 17.45 dec: 1081 bin: 100 0011 1001 87.16 dec: 1309 bin: 101 0001 1101
RDAY dec: 1309 bin: 101 0001 1101 dec: 1081 bin: 100 0011 1001 dec: 1024 bin: 100 0000 0000 dec: 967 bin: 011 1100 0111 dec: 739 bin: 010 1110 0011
DOUT (RDAX-RDAY) dec: -570 dec: -144 dec: 0 dec: 114 dec: 570
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
13/19 Rev.A
SCA103T Series
2.6
Self Test and Failure Detection Modes
To ensure reliable measurement results, the SCA103T 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 checks for the control register memory content. In a 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 goes below 102 counts. The SCA103T 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 its 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 both in 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 SCA103T. 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. 5V 0V 5V Vout V1 V2 V3 ST pin voltage
0V
T5
T1
T2
T3 T4
Figure 12.
Self test wave forms T4 [ms] Typ. 55 T5 [ms] Typ. 15 V2: Min 0.95*VDD (4.75V @Vdd=5V) V3: 0.95*V1-1.05*V1
Self test characteristics: T1 [ms] T2 [ms] T3 [ms] 20-100 Typ. 25 Typ. 30
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
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
14/19 Rev.A
SCA103T Series
T2 = Saturation delay T3 = Recovery time T4 = Stabilization time =T2+T3 T5 = Rise time during self test
2.7
Temperature Measurement
The SCA103T 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 by the following formula:
T=
Counts - 197 - 1.083
Temperature reading Temperature in C
Where: Counts T
The temperature measurement output is not calibrated. The internal temperature compensation routine uses relative results where absolute accuracy is not needed. If the temperature 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.
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
15/19 Rev.A
SCA103T Series
3 3.1
Application Information Recommended Circuit Diagrams and Printed Circuit Board Layouts
The SCA103T should be powered from well regulated 5 V DC power supply. Coupling of digital noise to power supply line should be minimized. A 100nF filtering capacitor between VDD pin 12 and GND plane must be used. The SCA103T has ratiometric output. To achieve the best performance use the same reference voltage for both the SCA103T and Analog/Digital converter. Use low pass RC filters with 5.11 k and 10nF on the SCA103T 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. External instrumentation amplifier connection example is shown below.
Figure 13.
Differential amplifier connection and layout example
The recommended connection example for SPI connection is shown below.
Figure 14.
SPI connection example
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
16/19 Rev.A
SCA103T Series
3.2
Recommended Printed Circuit Board Footprint
Figure 15.
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 The part weights Copper Nickel followed by Gold JEDEC standard: JESD22-B102-C RoHS compliant lead-free component. 0.1mm max. <1.2 g
Figure 16.
Mechanical dimensions of the SCA103T. (Dimensions in mm)
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
17/19 Rev.A
SCA103T Series
4.2
Reflow Soldering
The SCA103T is suitable for Sn-Pb eutectic and Pb-free soldering process and mounting with normal SMD pick-and-place equipment.
Figure 17.
Recommended SCA103T body temperature profile during reflow soldering. Ref. IPC/JEDEC J-STD-020B.
Profile feature
Average ramp-up rate (TL to TP) Preheat Temperature min (Tsmin) Temperature max (Tsmax) Time (min to max) (ts)
Sn-Pb Eutectic Assembly
3C/second max. 100C 150C 60-120 seconds
Pb-free Assembly
3C/second max. 150C 200C 60-180 seconds 3C/second max
Tsmax to T, Ramp up rate Time maintained above: Temperature (TL) Time (tL) 183C 60-150 seconds 240 +0/-5C 10-30 seconds 6C/second max 6 minutes max
217C 60-150 seconds 250 +0/-5C 20-40 seconds 6C/second max 8 minutes max
Peak temperature (TP) Time within 5C of actual Peak Temperature (TP) Ramp-down rate Time 25 to Peak temperature
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 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 the assembly process. Wave soldering is not recommended. Ultrasonic cleaning is not allowed. The sensing element may be damaged by an ultrasonic cleaning process.
* *
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
18/19 Rev.A
SCA103T Series
5
Document Change Control
Version
A
Date
1.9.-06
Change Description
Initial release
6
Contact Information
Finland (head office) VTI Technologies Oy P.O. Box 27 Myllynkivenkuja 6 FI-01621 Vantaa Finland Tel. +358 9 879 181 Fax +358 9 8791 8791 E-mail: sales@vti.fi Germany VTI Technologies Oy Branch Office Frankfurt Rennbahnstrasse 72-74 D-60528 Frankfurt am Main, Germany Tel. +49 69 6786 880 Fax +49 69 6786 8829 E-mail: sales.de@vti.fi USA VTI Technologies, Inc. One Park Lane Blvd. Suite 804 - East Tower Dearborn, MI 48126 USA Tel. +1 313 425 0850 Fax +1 313 425 0860 E-mail sales@vtitechnologies.com
Japan VTI Technologies Oy Tokyo Office Tokyo-to, Minato-ku 2-7-16 Bureau Toranomon 401105-0001 Japan Tel. +81 3 6277 6618 Fax +81 3 6277 6619
China VTI Technologies Shanghai Office 6th floor, Room 618 780 Cailun Lu Pudong New Area 201203 Shanghai P.R. China Tel. +86 21 5132 0418 or +86 21 5132 0400 *112 Fax +86 21 513 20 416 E-mail: forename.surname@vti.fi
To find out your local sales representative visit www.vti.fi
VTI Technologies reserves all rights to modify this document without prior notice.
VTI Technologies Oy www.vti.fi
Subject to changes Doc.Nr. 8261700
19/19 Rev.A

▲Up To Search▲

Price & Availability of SCA103T

	To Download SCA103T Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .