SCA103T Series Datasheet by Murata Electronics

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SCA103T Series
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Self test 2
Sensing
element 1
Sensing
element 2
SPI interface
Self test 1
Signal conditioning
and filtering
A/D conversion
Signal conditioning
and filtering
EEPROM
calibration
memory
9 ST_2
10 ST_1
12 VDD
6 GND
11 OUT_1
5 OUT_2
1 SCK
3 MISO
4 MOSI
7 CSB
Temperature
Sensor
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 Murata 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
Figure 1. Functional block diagram
Data Sheet
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TABLE OF CONTENTS
The SCA103T Differential 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 ....................................................................................................... 8
2.1 Differential Measurement ....................................................................................................... 8
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
SCA103T Series
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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)
-55°C to +125°C
-40°C to +125°C
Drop from 1 meter onto a concrete surface
(20000g). Powered or non-powered
1.2 Performance Characteristics
D/S
Condition
SCA103T
-D04
SCA103T
-D05
Units
Measuring range
D
Nominal
±15
±0.26
±30
±0.5
°
g
Frequency response
S
3dB LP (1
8-28
8-28
Hz
Offset (Output at 0g)
S
Ratiometric output
Vdd/2
Vdd/2
V
Offset calibration error
S
±0.057
±0.11
°
Offset Digital Output
S
1024
1024
LSB
Sensitivity
D
between 0…1° (2
16
280
8
140
V/g
mV/°
Sensitivity calibration error
S
±0.5
±0.5
%
Sensitivity Digital Output
D
6554
3277
LSB / g
Offset temperature
dependency
D
-25…85°C (typical)
±0.002
±0.002
°/°C
-40…125°C (max)
±0.29
±0.29
°
Sensitivity temperature
dependency
D
-25...85°C (typical)
±0.013
±0.013
%/°C
-40…125°C (max)
-2.5...+1
-2.5...+1
%
Typical non-linearity
D
Measuring range
±0.057
±0.11
°
Digital output resolution
D
between 0…1° (2
12
0.009
12
0.017
Bits
° / LSB
Output noise density
D
From DC...100Hz
0.0004
0.0004
Hz/
Analog output resolution
D
Bandwidth 10 Hz (3
0.0013
0.0013
°
Cross-axis sensitivity
S
Max.
4
4
%
Ratiometric error
S
Vdd = 4.75...5.25V
±1
±1
%
Note 1. The frequency response is determined by the sensing element’s internal gas damping.
Note 2. The angle output has SIN curve relationship to voltage output - refer to chapter 2.2
Note 3. Resolution = Noise density * (bandwidth)
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1.3 Electrical Characteristics
Parameter
Condition
Min.
Typ
Max.
Units
Supply voltage Vdd
4.75
5.0
5.25
V
Current
consumption
Vdd = 5 V; No load
4
5
mA
Operating
temperature
-40
+125
°C
Analog resistive
output load
Vout to Vdd or GND
10
kOhm
Analog capacitive
output load
Vout to Vdd or GND
20
nF
Start-up delay
Reset and parity check
10
ms
1.4 SPI Interface DC Characteristics
Parameter
Conditions
Symbol
Min
Typ
Max
Unit
Input terminal CSB
Pull up current
VIN = 0 V
IPU
13
22
35
A
Input high voltage
VIH
4
Vdd+0.3
V
Input low voltage
VIL
-0.3
1
V
Hysteresis
VHYST
0.23*Vdd
V
Input capacitance
CIN
2
pF
Input terminal MOSI, SCK
Pull down current
VIN = 5 V
IPD
9
17
29
A
Input high voltage
VIH
4
Vdd+0.3
V
Input low voltage
VIL
-0.3
1
V
Hysteresis
VHYST
0.23*Vdd
V
Input capacitance
CIN
2
pF
Output terminal MISO
Output high voltage
I > -1mA
VOH
Vdd-
0.5
V
Output low voltage
I < 1 mA
VOL
0.5
V
Tristate leakage
0 < VMISO <
Vdd
ILEAK
5
100
pA
1.5 SPI Interface AC Characteristics
Parameter
Condition
Min.
Typ.
Max.
Units
Output load
@500kHz
1
nF
SPI clock frequency
500
kHz
Internal A/D conversion time
150
s
Data transfer time
@500kHz
38
s
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CSB
SCK
MOSI
MISO
TLS1
TCH
THOL
TSET
TVAL1
TVAL2
TLZ
TLS2
TLH
MSB in
MSB out
LSB in
LSB out
DATA out
DATA in
TCL
1.6 SPI Interface Timing Specifications
Parameter
Conditions
Symbol
Min.
Typ.
Max.
Unit
Terminal CSB, SCK
Time from CSB (10%)
to SCK (90%)
TLS1
120
ns
Time from SCK (10%)
to CSB (90%)
TLS2
120
ns
Terminal SCK
SCK low time
Load
capacitance at
MISO < 2 nF
TCL
1
s
SCK high time
Load
capacitance at
MISO < 2 nF
TCH
1
s
Terminal MOSI, SCK
Time from changing MOSI
(10%, 90%) to SCK (90%).
Data setup time
TSET
30
ns
Time from SCK (90%) to
changing MOSI (10%,90%).
Data hold time
THOL
30
ns
Terminal MISO, CSB
Time from CSB (10%) to stable
MISO (10%, 90%).
Load
capacitance at
MISO < 15 pF
TVAL1
10
100
ns
Time from CSB (90%) to high
impedance state of
MISO.
Load
capacitance at
MISO < 15 pF
TLZ
10
100
ns
Terminal MISO, SCK
Time from SCK (10%) to stable
MISO (10%, 90%).
Load
capacitance at
MISO < 15 pF
TVAL2
100
ns
Terminal CSB
Time between SPI cycles, CSB at high
level (90%)
TLH
15
s
When using SPI commands RDAX, RDAY,
RWTR: Time between SPI cycles, CSB at
high level (90%)
TLH
150
s
Figure 2. Timing diagram for SPI communication
SUBBED SUBBED
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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.
1
2
3
4
5
6 7
8
9
10
11
12SCK
Ext_C_1
MISO
MOSI
OUT_2
VSS CSB
Ext_C_2
ST_2
ST_1/Test_in
OUT_1
VDD
Figure 3. SCA103T electrical connection
No.
Node
I/O
Description
1
SCK
Input
Serial clock
2
NC
Input
No connect, left floating
3
MISO
Output
Master in slave out; data output
4
MOSI
Input
Master out slave in; data input
5
Out_2
Output
Output 2 (Ch 2)
6
GND
Supply
Ground
7
CSB
Input
Chip select (active low)
8
NC
Input
No connect, left floating
9
ST_2
Input
Self test input for Ch 2
10
ST_1
Input
Self test input for Ch 1
11
Out_1
Output
Output 1(Ch 1)
12
VDD
Supply
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 ± 3 standard deviation) and specification limits are presented in
following diagrams. The 3 sigma limits represents 99.73% of the SCA103T population.
SCK
MISO
MOSI
OUT_2
GND
VDD
OUT_1
ST_1
ST_2
CSB
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031.0*0032.0*00005.0*0000005.0 23 TTTScorr
temperature dependency of SCA103T offset (differential output)
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
-40 -20 0 20 40 60 80 100 120
Temp [°C]
Differential offset error [degrees]
average
+3 Sigma
-3 Sigma
specification limit
specification limit
Temperature dependency of SCA103T sensitivity [%] (differential output)
-3
-2.5
-2
-1.5
-1
-0.5
0
0.5
1
1.5
-40 -20 0 20 40 60 80 100 120
Temp [°C]
Differential sensitivity error [%]
average
+3 Sigma
-3 Sigma
specification
limit
specification
limit
Figure 4. Typical temperature dependency of SCA103T offset
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:
Where:
Scorr: 3rd order polynome fitted to average sensitivity temperature dependency curve
T temperature in °C (Refer to paragraph 2.7- Temperature Measurement)
SCA103T Series
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)100/1(* ScorrSENSSENScomp
The temperature dependency of 3rd order compensated SCA103T sensitivity [%]
(differential output)
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
-40 -20 0 20 40 60 80
Temp [°C]
Differential sensitivity error [%]
compensated
average
+3 Sigma limit
-3 Sigma limit
The calculated compensation curve can be used to compensate for the temperature dependency of
the SCA103T sensitivity by using following equation:
Where:
SENScomp temperature compensated sensitivity
SENS 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.
Figure 6. The temperature dependency of 3rd order compensated SCA103T sensitivity
2 Functional Description
2.1 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.
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SCA103T-D04 outputs and differential amplifier output
-6.0
-5.0
-4.0
-3.0
-2.0
-1.0
0.0
1.0
2.0
3.0
4.0
5.0
6.0
-20 -15 -10 -5 0 5 10 15 20
Tilt angle [ ° ]
Output [V]
SCA103T OUT_1
SCA103T OUT_2
Differential output
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.
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.
Figure 8. Behavior of the analog output
The analog output can be transferred to angle by using the following equation for conversion:
ySensitivit
OffsetVDout
arcsin
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.
OUT1 < OUT1 =2.5V < OUT1
OUT2 > OUT2 =2.5V > OUT2
DIFF < DIFF =0 V <DIFF
Earth's gravity
2
1
D
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ySensitivit
OffsetVDout
Angles close to 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:
Where: Sensitivity = 280mV/° with SCA103T-D04 or Sensitivity= 140mV/° with SCA103T-D05
Tilt angle [°]
Straight line conversion error [°]
0
0
1
0.0027
2
0.0058
3
0.0094
4
0.0140
5
0.0198
10
0.0787
15
0.2185
30
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/D-
converter) 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 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 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).
DATA OUT (MOSI)
DATA IN (MISO)
SERIAL CLOCK (SCK)
SS0
SS1
SS2
SS3
MASTER
MICROCONTROLLER
SI
SO
SCK
CS
SLAVE
SI
SO
SCK
CS
SI
SO
SCK
CS
SI
SO
SCK
CS
Figure 9. Typical SPI connection
the ou'put data is shifted out in garallel with the ingut data
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The SPI interface in Murata 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 master out slave in µP → SCA103T
MISO master in slave out SCA103T → µP
SCK serial clock µP → SCA103T
CSB chip select (low active) µP → 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.
Command
name
Command
format
Description:
MEAS
00000000
Measure mode (normal operation mode after power on)
RWTR
00001000
Read temperature data register
STX
00001110
Activate Self test for X-channel
STY
00001111
Activate Self test for Y-channel
RDAX
00010000
Read X-channel acceleration
RDAY
00010001
Read Y-channel acceleration
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 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.
can M130 csB sex MOS] mso m'm an
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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 µs. The load operation
is disabled whenever the CSB signal is low, hence CSB must stay high at least 150 µs 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.
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
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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
LSB/g
LSBLSB
arcsin 0@
Sens
DD outout
where;
Dout differential digital output (RDAX RDAY)
Dout@0° digital offset value, nominal value = 0 in differential mode
angle
Sens sensitivity of the device. (SCA103T-D04: 6554, SCA103T-D05: 3277)
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
[°]
Acceleration
[mg]
RDAX
RDAY
DOUT
(RDAXRDAY)
-5
-87.16
dec: 739
bin: 010 1110 0011
dec: 1309
bin: 101 0001 1101
dec: -570
-1
-17.45
dec: 967
bin: 011 1100 0111
dec: 1081
bin: 100 0011 1001
dec: -144
0
0
dec: 1024
bin: 100 0000 0000
dec: 1024
bin: 100 0000 0000
dec: 0
1
17.45
dec: 1081
bin: 100 0011 1001
dec: 967
bin: 011 1100 0111
dec: 114
5
87.16
dec: 1309
bin: 101 0001 1101
dec: 739
bin: 010 1110 0011
dec: 570
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
5V V3 T2 T3
SCA103T Series
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083.1
197
Counts
T
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.
Figure 12. Self test wave forms
Self test characteristics:
T1 [ms]
T2 [ms]
T3 [ms]
T4 [ms]
T5 [ms]
V2:
V3:
20-100
Typ. 25
Typ. 30
Typ. 55
Typ. 15
Min 0.95*VDD
(4.75V @Vdd=5V)
0.95*V1-1.05*V1
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
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:
Where:
Counts Temperature reading
T 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
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.
Vout
5V
0 V
T5
T1
T2
T3
T4
V1
V2
V3
ST pin
voltage
0 V
5 V
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SCA103T Series
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3 Application Information
3.1 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 kΩ 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
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SCA103T Series
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3.2 Recommended Printed Circuit Board Footprint
Figure 15. Recommended PCB footprint
4 Mechanical Specifications and Reflow Soldering
4.1 Mechanical Specifications (Reference only)
Lead frame material: Copper
Plating: Nickel followed by Gold
Solderability: JEDEC standard: JESD22-B102-C
RoHS compliance: RoHS compliant lead-free component.
Co-planarity error 0.1mm max.
The part weights <1.2 g
Figure 16. Mechanical dimensions of the SCA103T. (Dimensions in mm)
Temperature :9 2s Ramprup [Pflfi' Criucal Zone TL to Tp Preheal l 25°C to Peak Time |=>
SCA103T Series
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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
Sn-Pb Eutectic
Assembly
Pb-free Assembly
Average ramp-up rate (TL to TP)
3°C/second max.
3°C/second max.
Preheat
- Temperature min (Tsmin)
- Temperature max (Tsmax)
- Time (min to max) (ts)
100°C
150°C
60-120 seconds
150°C
200°C
60-180 seconds
Tsmax to T, Ramp up rate
3°C/second max
Time maintained above:
- Temperature (TL)
- Time (tL)
183°C
60-150 seconds
217°C
60-150 seconds
Peak temperature (TP)
240 +0/-5°C
250 +0/-5°C
Time within 5°C of actual Peak Temperature (TP)
10-30 seconds
20-40 seconds
Ramp-down rate
6°C/second max
6°C/second max
Time 25° to Peak temperature
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 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.

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