SCA61T-FA1H1G скачать даташит

SCA61T-FA1H1G скачать даташит
SCA61T Series
Data Sheet
THE SCA61T INCLINOMETER SERIES
The SCA61T Series is a 3D-MEMS-based single axis inclinometer family that provides instrumentation grade
performance for leveling applications. Low temperature dependency, high resolution and low noise together with
robust sensing element design make the SCA61T ideal choice for leveling instruments. The VTI inclinometers are
insensitive to vibration, due to their over damped sensing elements and can withstand mechanical shocks of
20000 g.
Features
•
•
•
•
•
•
•
•
•
Measuring ranges ±30° SCA61T-FAHH1G
and ± 90° SCA61T-FA1H1G
0.0025° 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
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
Leveling instruments
Acceleration and motion measurement
8 VDD
Sensing
element
Signal conditioning
and filtering
7 OUT
A/D conversion
6 ST
Self test 1
EEPROM
calibration
memory
Temperature
Sensor
1 SCK
SPI interface
2 MISO
3 MOSI
5 CSB
4 GND
Figure 1.
VTI Technologies Oy
www.vti.fi
Functional block diagram
Subject to changes
Doc. nr. 8261900
1/18
Rev.A
SCA61T Series
TABLE OF CONTENTS
The SCA61T 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
1.9
Additional External Compensation ..........................................................................................7
2 Functional Description .......................................................................................................9
2.1
Measuring Directions ................................................................................................................9
2.2
Voltage to Angle Conversion....................................................................................................9
2.3
Ratiometric Output ....................................................................................................................9
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
5 Document Change Control...............................................................................................18
6 Contact Information ..........................................................................................................18
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
2/18
Rev.A
SCA61T Series
1
Electrical Specifications
The SCA61T product family comprises two versions, the SCA61T-FAHH1G and the SCA61TFA1H1G, that differ in measurement range. The product version specific performance
specifications are listed in the following table below. All other specifications are common to 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
1.2
-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 on a concrete surface
(20000g). Powered or non-powered
Performance Characteristics
Parameter
Condition
Measuring range
Nominal
Frequency response
Offset (Output at 0g)
Offset calibration error
Offset Digital Output
Sensitivity
–3dB LP (1
Ratiometric output
between 0…1° (2
Sensitivity calibration
error
Sensitivity Digital Output
Offset temperature
dependency
Sensitivity temperature
dependency
Typical non-linearity
Digital output resolution
Output noise density
Analog output resolution
Ratiometric error
Cross-axis sensitivity
Long term Stability (4
Note 1.
Note 2.
Note 3.
Note 4.
VTI Technologies Oy
www.vti.fi
-25…85°C (typical)
-40…125°C (max)
-25...85°C (typical)
-40…125°C (max)
Measuring range
between 0…1° (2
From DC...100Hz
(3
Bandwidth 10 Hz
Vdd = 4.75...5.25V
Max.
SCA61TFAHH1G
±30
±0.5
8-28
Vdd/2
±0.11
1024
4
70
±0.5
SCA61TFA1H1G
±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
0.0025
±1
4
<0.014
0.0025
±1
4
<0.014
°
%
%
°
°
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 refer to paragraph 2.2
Resolution = Noise density * √(bandwidth)
Power continuously connected (@ 23°C).
Subject to changes
Doc. nr. 8261900
3/18
Rev.A
SCA61T 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
2.5
5.25
4
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
1.5
Condition
Conditions
Symbol
Min
Typ
Max
1.4.1.1.1 Input terminal CSB
Pull up current
VIN = 0 V
Input high voltage
Input low voltage
Hysteresis
Input capacitance
IPU
VIH
VIL
VHYST
CIN
13
4
-0.3
22
35
Vdd+0.3
1
µA
V
V
V
pF
1.4.1.1.2 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
µA
V
V
V
Input capacitance
CIN
2
pF
1.4.1.1.3 Output terminal MISO
Output high voltage
I > -1mA
VOH
Output low voltage
Tristate leakage
VOL
ILEAK
I < 1 mA
0 < VMISO <
Vdd
0.23*Vdd
2
17
Vdd0.5
Unit
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
VTI Technologies Oy
www.vti.fi
@500kHz
Subject to changes
Doc. nr. 8261900
Min.
Typ.
150
38
Max.
Units
1
500
nF
kHz
µs
µs
4/18
Rev.A
SCA61T 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
µs
TCH
1
µs
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%).
Typ.
Max.
Unit
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%)
TLS1
TCH
TLH
15
µs
TLH
150
µs
TCL
TLS2
TLH
CSB
SCK
THOL
MOSI
TVAL1
MISO
Figure 2.
VTI Technologies Oy
www.vti.fi
TSET
MSB in
DATA in
LSB in
TVAL2
MSB out
TLZ
DATA out
LSB out
Timing diagram for SPI communication
Subject to changes
Doc. nr. 8261900
5/18
Rev.A
SCA61T 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 pin (pin
6). If ST feature is not used pin 6 must be left floating or connected to GND. Inclination signal is
provided from pin OUT.
1 SCK
8 VDD
2 MISO
7 OUT
3 MOSI
6 ST
Figure 3.
No.
1
2
3
4
5
6
7
8
1.8
SCA61T electrical connection
Node
SCK
MISO
MOSI
GND
CSB
ST
Out
VDD
I/O
Input
Output
Input
Supply
Input
Input
Output
Supply
Description
Serial clock
Master in slave out; data output
Master out slave in; data input
Ground
Chip select (active low)
Self test input
Output
Positive supply voltage (+5V DC)
Typical Performance Characteristics
Typical offset and sensitivity temperature dependencies of SCA61T are presented in following
diagrams. These results represent the typical performance of SCA61T 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 SCA61T population.
Temperature dependency of SCA61T offset
1.0
specification
limit
0.8
Offset error [degrees]
0.6
0.4
0.2
average
0.0
+3 sigma
-0.2
-3 sigma
-0.4
-0.6
specification
limit
-0.8
-1.0
-40
-20
0
20
40
60
80
100
120
Temp [°C]
Figure 4.
VTI Technologies Oy
www.vti.fi
Typical temperature dependency of the SCA61T offset
Subject to changes
Doc. nr. 8261900
6/18
Rev.A
SCA61T Series
Temperature dependency of SCA61T sensitivity
specification
limit
1.0
sensitivity error [%]
0.5
0.0
-0.5
average
+3 sigma
-1.0
-3 sigma
-1.5
-2.0
-2.5
-40
-20
0
20
40
60
80
100
120
specification
limit
Temp [°C]
Figure 5.
1.9
Typical temperature dependency of SCA61T sensitivity
Additional External Compensation
To achieve the best possible accuracy, the temperature measurement information and typical
temperature dependency curves can be used for SCA61T offset and sensitivity temperature
dependency compensation. The equation for the fitted 3rd order polynome curve for offset
compensation is:
Offcorr = −0.0000005 * T 3 + 0.0000857 * T 2 − 0.0032 * T + 0.0514
Where:
Offcorr:
T
3rd 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 for the temperature dependency
of the SCA61T offset by using the following equation:
OFFSETcomp = Offset − Offcorr
Where:
OFFSETcomp
temperature compensated offset in degrees
Offset
Nominal offset in degrees
The equation for the fitted 2nd order polynome curve for sensitivity compensation is:
Scorr = −0.00011* T 2 + 0.0019 * T + 0.0362
Where:
Scorr:
T
2nd 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 SCA61T sensitivity by using the following equation:
SENScomp = SENS * (1 + Scorr / 100)
Where:
SENScomp
SENS
temperature compensated sensitivity
Nominal sensitivity (4V/g SCA61T-FAHH1G, 2V/g SCA61T-FA1H1G)
The typical offset and sensitivity temperature dependency after external compensation is shown in
the following diagrams.
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
7/18
Rev.A
SCA61T Series
Temperature dependency of externally compensated SCA61T offset
1.0
0.8
Offset error [degrees]
0.6
0.4
0.2
average
0.0
+3 sigma
-0.2
-3 sigma
-0.4
-0.6
-0.8
-1.0
-40
-20
0
20
40
60
80
100
120
Temp [°C]
Figure 6.
The temperature dependency of externally compensated SCA61T offset
Temperature dependency of externally compensated SCA61T sensitivity
1.0
0.8
sensitivity error [%]
0.6
0.4
0.2
0.0
average
+3 sigma
-0.2
-3 sigma
-0.4
-0.6
-0.8
-1.0
-40
-20
0
20
40
60
80
100
120
Temp [°C]
Figure 7.
VTI Technologies Oy
www.vti.fi
The temperature dependency of externally compensated SCA61T sensitivity
Subject to changes
Doc. nr. 8261900
8/18
Rev.A
SCA61T Series
2
2.1
Functional Description
Measuring Directions
X-axis
VOUT >
> VOUT
The measuring direction of the SCA61T
Figure 8.
2.2
VOUT =2.5V
Voltage to Angle Conversion
Analog output can be transferred to angle using the following equation for conversion:
⎛ Vout − Offset ⎞
⎟⎟
⎝ Sensitivity ⎠
α = arcsin⎜⎜
where: Offset = output of the device at 0° inclination position, Sensitivity is the sensitivity of the
device and VDout is the output of SCA61T. The nominal offset is 2.5 V and the sensitivity is 4 V/g
with SCA61T-FAHH1G and 2 V/g with SCA61T-FA1H1G.
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. The following table shows
the angle measurement error if straight line conversion is used.
Straight line conversion equation:
α=
Vout − Offset
Sensitivity
Where: Sensitivity = 70mV/° with SCA61T-FAHH1G or Sensitivity= 35mV/° with SCA61T-FA1H1G
Tilt angle [°]
0
1
2
3
4
5
10
15
30
2.3
Straight line conversion error [°]
0
0.0027
0.0058
0.0094
0.0140
0.0198
0.0787
0.2185
1.668
Ratiometric Output
Ratiometric output means that zero offset point and sensitivity of the sensor are proportional to the
supply voltage. If the SCA61T supply voltage is fluctuating, the SCA61T output will also vary.
When the same reference voltage for both the SCA61T sensor and the measuring part (A/Dconverter) is used, the error caused by reference voltage variation is automatically compensated
for.
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
9/18
Rev.A
SCA61T Series
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 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 with 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 VTI products is designed to support any micro controller that uses an SPI bus.
Communication can be carried out by a software or hardware based SPI. Please note that in the
case of a 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 → SCA61T
SCA61T → µP
µP → SCA61T
µP → SCA61T
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:
•
•
•
•
•
•
•
VTI Technologies Oy
www.vti.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)
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 SCA61T’s internal registers
Subject to changes
Doc. nr. 8261900
10/18
Rev.A
SCA61T Series
•
•
•
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 is 5300 samples per sec / channel
The 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
RDSR
RLOAD
STX
RDAX
Command
Format
00000000
00001000
00001010
00001011
00001110
00010000
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
Read X-channel acceleration through SPI
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 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 the RWTR command in order to guarantee correct data. The data transfer is presented in
Figure 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
2
1
0
2
1
0
SC K
D A T A IN
C O M M AN D
M OSI
7
6
5
7
6
5
Figure 10.
3
D A TA O U T
H IG H IM PED AN C E
M ISO
4
4
3
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.
Read X-channel acceleration (RDAX) accesses the AD converted X-channel acceleration signal
stored in acceleration data register X.
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.
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
11/18
Rev.A
SCA61T Series
CSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
5
4
3
16
17
18
1
0
SCK
COM M AND
M OSI
DATA OUT
H IG H IM P E D A N C E
M IS O
10
8
7
6
2
Command and 11 bit acceleration data transmission over the SPI
Figure 11.
2.5
9
Digital Output to Angle Conversion
The acceleration measurement results in RDAX data register are in 11 bit digital word format. The
data range is from 0 to 2048. The nominal content of RDAX data register in zero angle position is:
Binary: 100 0000 0000
Decimal: 1024
The transfer function from differential digital output to angle can be presented as
⎛ Dout [LSB] − [email protected] 0° [LSB] ⎞
⎟
⎟
Sens [LSB/g]
⎝
⎠
α = arcsin⎜⎜
where;
Dout
[email protected]°
α
Sens
digital output (RDAX)
digital offset value, nominal value = 1024
angle
sensitivity of the device. (SCA61T-FAHH1G: 1638, SCA61T-FA1H1G: 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.
Angle
[°]
-5
Acceleration
[mg]
-87.16
-1
-17.45
0
0
1
17.45
5
87.16
VTI Technologies Oy
www.vti.fi
RDAX (SCA61TFAHH1G)
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
Subject to changes
Doc. nr. 8261900
RDAX (SCA61TFA1H1G)
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
12/18
Rev.A
SCA61T Series
2.6
Self Test and Failure Detection Modes
To ensure reliable measurement results the SCA61T 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 voltage is forced to go close to ground level (<0.25 V) and SPI outputs goes
below 102 counts.
The SCA61T 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 command, and de-activated by a MEAS command. Self test can be
also activated applying logic”1” (positive supply voltage level) to ST pin (pins 6) of SCA61T. The
self test Input high voltage level is 4 – Vdd+0.3 V and input low voltage level is 0.3 – 1 V.
5V
ST pin
voltage
0V
5V
Vout
V1
V2
T1
0V
T5
Figure 12.
V3
T3
T2
T4
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:
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
13/18
Rev.A
SCA61T Series
T1 [ms]
20-100
2.7
T2 [ms]
Typ. 25
T3 [ms]
Typ. 30
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 SCA61T 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
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. 8261900
14/18
Rev.A
SCA61T Series
3
3.1
Application Information
Recommended Circuit Diagrams and Printed Circuit Board Layouts
The SCA61T should be powered from well regulated 5 V DC power supply. Coupling of digital
noise to power supply line should be minimized. 100nF filtering capacitor between VDD pin 8 and
GND plane must be used.
The SCA61T has ratiometric output. To get best performance use the same reference voltage for
both the SCA61T and Analog/Digital converter.
Use low pass RC filter with 5.11 kΩ and 10nF on the SCA61T output to minimize clock noise.
Locate the 100nF power supply filtering capacitor close to VDD pin 8. Use as short trace length as
possible. Connect the other end of capacitor directly to 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 13.
Analog connection and layout example
Figure 14.
SPI connection example
VTI Technologies Oy
www.vti.fi
Subject to changes
Doc. nr. 8261900
15/18
Rev.A
SCA61T Series
3.2
Recommended Printed Circuit Board Footprint
Figure 15.
4
4.1
Recommended PCB footprint
Mechanical Specifications and Reflow Soldering
Mechanical Specifications (Reference only)
Lead frame material:
Plating:
Solderability:
RoHS compliance:
Co-planarity error
The part weights
Figure 16.
VTI Technologies Oy
www.vti.fi
Copper
Nickel followed by Gold
JEDEC standard: JESD22-B102-C
RoHS compliant lead free component.
0.1mm max.
<1 g
Mechanical dimensions of the SCA61T. (Dimensions in mm)
Subject to changes
Doc. nr. 8261900
16/18
Rev.A
SCA61T Series
4.2
Reflow Soldering
The SCA61T is suitable for Sn-Pb eutectic and Pb- free soldering process and mounting with
normal SMD pick-and-place equipment.
Figure 17.
Recommended SCA61T body temperature profile during reflow soldering. Ref.
IPC/JEDEC J-STD-020B.
Profile feature
Average ramp-up rate (TL to TP)
Sn-Pb Eutectic
Assembly
Pb-free Assembly
3°C/second max.
3°C/second max.
150°C
Preheat
-
Temperature min (Tsmin)
100°C
-
Temperature max (Tsmax)
150°C
200°C
-
Time (min to max) (ts)
60-120 seconds
60-180 seconds
Tsmax to T, Ramp up rate
3°C/second max
Time maintained above:
-
Temperature (TL)
-
Time (tL)
Peak temperature (TP)
Time within 5°C of actual Peak Temperature (TP)
Ramp-down rate
Time 25° to Peak temperature
183°C
217°C
60-150 seconds
60-150 seconds
240 +0/-5°C
250 +0/-5°C
10-30 seconds
20-40 seconds
6°C/second max
6°C/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:
•
•
•
•
VTI Technologies Oy
www.vti.fi
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 assembly process.
Wave soldering is not recommended.
Ultrasonic cleaning is not allowed. The sensing element may be damaged by ultrasonic
cleaning process.
Subject to changes
Doc. nr. 8261900
17/18
Rev.A
SCA61T Series
5
6
Document Change Control
Version
Date
Change Description
A
1.9.-06
Initial release
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: [email protected]
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: [email protected]
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 [email protected]
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: [email protected]
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. 8261900
18/18
Rev.A
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement