ETC1 MS5534AP Barometer module Datasheet

MS5534A
BAROMETER MODULE
♦
♦
♦
♦
Integrated pressure sensor
Pressure range 300-1100 mbar
15 Bit ADC
6 coefficients for a software
compensation stored on-chip
♦ 3-wire serial interface
♦ 1 system clock line (32.768 kHz)
♦ Low voltage / low power
DESCRIPTION
The MS5534A is a SMD-hybrid device including a piezoresistive pressure sensor and an ADC-Interface IC. It
provides a 16 Bit data word from a pressure- and temperature-dependent voltage. Additionally the module
contains 6 readable coefficients for a highly accurate software calibration of the sensor. MS5534A is a lowpower, low-voltage device with automatic power down (ON/OFF) switching. A 3-wire interface is used for all
communications with a microcontroller. Sensor packaging options are plastic or metal cap.
FEATURES
•
•
•
•
•
•
APPLICATIONS
•
•
•
•
15-Bit ADC resolution
Supply voltage 2.2 V to 3.6 V
Low Supply current
-40°C to +60°C
Small size
No external components required
Mobile altimeter/barometer systems
Weather control systems
Adventure or multi-mode watches
GPS Receivers
BLOCK DIAGRAM
VDD
MCLK
Input MUX
SENSOR
+IN
-IN
Digital
Interface
ADC
dig.
Filter
Sensor
Interface IC
DIN
DOUT
SCLK
Memory
(PROM)
64 bits
SGND
GND
Fig.: 1 Block Diagram 5534
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July 17th, 2002
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PIN CONFIGURATION
PEN 7
6
VDD
6
5
MCLK
5
4
DIN
4
3
DOUT
3
2
SCLK
2
1
GND
1
PV 8
Fig. 2: Pin configuration of MS5534
PIN DESCRIPTION
Pin Name
Pin
Type
Function
VDD
MCLK
DIN
DOUT
SCLK
GND
PV
PEN
6
5
4
3
2
1
8
7
P
I
I
O
I
G
N
I
Positive Supply Voltage
Master Clock (32.768kHz)
Data Input
Data Output
Serial Data Clock
Ground
Negative Programming Voltage
Programming Enable
Note: Pins 7 (PEN) and 8 (PV) are only used by the manufacturer for calibration purposes and should not be
connected.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Conditions
Min
Max
Unit
V
bar
abs
o
C
Supply Voltage
Overpressure
VDD
P
-0.3
4
4
Storage Temperature
TStg
-20
+70
Notes:
1. Storage and operation in an environment of dry and non-corrosive gases.
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RECOMMENDED OPERATING CONDITIONS
(T=25°C, VDD=3.0V unless noted otherwise)
Parameter
Supply Voltage
Supply Current,
average (1)
during conversion (2)
standby (no conversion)
Current consumption into
MCLK (3)
Operating pressure range
Symbol
VDD
Conditions
Typ.
3.0
Max
3.6
Unit
V
3.5
0.5
µA
mA
µA
µA
VDD = 3.0 V
Iavg
ISC
Iss
5
1
MCLK=32768Hz
p
300
Ta
-10
Operating temperature
range
Conversion time
Tconv
External clock signal (4)
MCLK
1100
+25
MCLK=32768Hz
Duty cycle of MCLK
Serial Data Clock
Min.
2.2
SCLK
+60
mbar
abs.
°C
35
ms
30000
32768
35000
Hz
40/60
50/50
60/40
%
500
kHz
Notes:
1. Under the assumption of one conversion every second. Conversion means either a pressure or a
temperature measurement started by a command to the serial interface of MS5534.
2. During conversion the sensor will be switched on and off in order to reduce power consumption; the total on
time within a conversion is about 2ms.
3. This value can be reduced by switching off MCLK while MS5534 is in standby mode.
4. It is strongly recommended that a crystal oscillator be used because the device is sensitive to clock jitter. A
square-wave form of the clock signal is a must.
5. Reliable operation requires protection of the pressure sensor from direct contact with light.
6. Power supply pins (VDD, GND) must be decoupled with a tantalum (47µF) capacitor placed close to the
module.
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ELECTRICAL CHARACTERISTICS
Digital inputs
(T=-40°C .. 60°C)
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
Input High Voltage
VIH
VDD = 2.2…3.6V
Input Low Voltage
VIL
VDD = 2.2…3.6 V
80%
VDD
0%
VDD
100%
VDD
20%
VDD
V
Signal Rise Time
tR
200
ns
Signal Fall Time
tf
200
ns
V
Digital outputs
(T=-40°C .. 60°C, VDD = 2.2V..3.6V)
Parameter
Symbol
Conditions
Min
Output High Voltage
VOH
ISource = 0.6 mA
Output Low Voltage
VOL
ISink = 0.6 mA
75%
VDD
0%
VDD
Typ
Max
Unit
100%
VDD
20%
VDD
V
V
Signal Rise Time
tr
200
ns
Signal Fall Time
tf
200
ns
AD-converter
(T=25°C, VDD =3.0V)
Parameter
Symbol
Conditions
Resolution (1)
Conversion Time
Min
Typ
Max
15
MCLK=32768Hz
Accuracy (2)
2
Unit
Bit
35
ms
7
LSB
Notes:
7. The ADC output range is from 5,000 counts to 37,000 counts, thus providing a 16-Bit output word.
8. Accuracy limited by the non-linearity of the ADC.
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PRESSURE OUTPUT CHARACTERISTICS
With the calibration data provided by the MS5534 system (stored in the interface IC) the following characteristics
can be achieved:
Parameter
Resolution
Absolute Pressure Accuracy
Relative Pressure Accuracy
Maximum Error over
Temperature
Long-term Stability
Maximum Error over Supply
Voltage
Conditions
Min
p = 750 …1100mbar
Ta = 25°C
p = 750 …1100mbar
Ta = 25°C
Ta = -10…+60°C
p = const.
Max
Unit
mbar
Note
1
-1.5
+1.5
mbar
2
-0.5
+0.5
mbar
3
-1
+1
mbar
4
-1
+6
mbar
5
mbar
6
12 month
VDD = 2.2…3.6V
Typ
0.1
-1
-1.5
0
+1.5
mbar/V
Notes:
1. A stable pressure reading of the given resolution requires to take the average of 2 to 4 subsequent pressure
values due to noise of the ADC. A better resolution can be obtained with more averaging.
2. Maximum error of pressure reading over the pressure range.
3. Maximum error of pressure reading over the pressure range after offset adjustment at one pressure point.
4. With the second-order temperature compensation as described in Section "Calculation of pressure using
compensation coefficients C1 to C5".
5. With the first-order temperature compensation as described in Section "Calculation of pressure using
compensation coefficients C1 to C5".
6. The long-term stability is measured with non-soldered devices
TEMPERATURE OUTPUT CHARACTERISTICS
This temperature information is not required for most applications, but it is necessary to allow for temperature
compensation of the pressure output. The reference temperature is 20°C.
Parameter
Conditions
Max
Unit
0.005
0.015
°C
at reference temperature
-0.8
0.8
°C
VDD = 2.2…3.6V
-0.08
+ 0.08
°C/V
Resolution
Accuracy
Maximum Error over Supply
Voltage
Min
Typ
Notes:
1. Refer to the paragraph second-order temperature compensation in the section ‘FUNCTION’
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TYPICAL PERFORMANCE CURVES
ADC-value vs Pressure (typical)
20000
19000
18000
ADC-value (LSB)
17000
16000
Temp. -10°C
Temp.+25°C
15000
Temp.+60°C
14000
13000
12000
11000
1100
1000
900
800
700
600
500
400
300
10000
Pressure (m bar)
ADC-value D2 vs Temperature (typical)
30000
29000
28000
ADC-value (LSB)
27000
26000
25000
24000
23000
22000
21000
20000
-10
0
10
20
30
40
50
60
Temperature (°C)
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Absolute pressure accuracy after calibration (typical)
3.5
3
Linearity error (mbar)
2.5
-10°C (standard
calculation)
2
-10°C (2nd order
temperature
compensation)
+60°C
1.5
1
0.5
0
+25°C
-0.5
-1
-1.5
300
400
500
600
700
800
900
1000
1100
Pressure (m bar)
4
4
3
3
2
2
1
1
0
0
-1
-1
-2
-2
-3
-4
-10
-3
Pressure Error
(standard
compensation)
Pressure Error (mbar)
Temperature Error (°C)
Accuracy vs temperature (typical)
Pressure Error
(2nd order
temperature
compensation)
Temperature Error
(standard
calculation)
Temperature Error
(w ith 2nd order
calculation)
-4
0
10
20
30
40
50
60
Temperature (°C)
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Pressure error vs supply voltage (typical)
0.4
0.3
Pressure error (mbar)
0.2
0.1
0
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
Press. 300mbar
Press. 700mbar
-0.1
Press. 1100mbar
-0.2
-0.3
-0.4
Voltage (V)
Temperature error (25°C) vs supply voltage (typical)
0.15
Temperature error (°C)
0.1
0.05
0
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
-0.05
-0.1
-0.15
Voltage (V)
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FUNCTION
General
The MS5534 consists of a piezoresistive sensor and a sensor interface IC. The main function of the MS5534 is to
convert the uncompensated analog output voltage from the piezoresistive pressure sensor to a 16-Bit digital
value, as well as providing a 16-Bit digital value for the temperature of the sensor.
• measured pressure (16-Bit)
• measured temperature (16-Bit)
“D1”
“D2”
As the output voltage of a pressure sensor is strongly dependent on temperature and process tolerances, it is
necessary to compensate for these effects. This compensation procedure must be performed by software using
an external microcontroller.
Factory calibration
Every module is individually factory calibrated at two temperatures and two pressures. As a result, 6 coefficients
necessary to compensate for process variations and temperature variations are calculated and stored in the 64Bit PROM of each module. These 64-Bit (partitioned into four words of 16-Bit) must be read by the
microcontroller software and used in the program converting D1 and D2 into compensated pressure and
temperature values.
Pressure and temperature measurement
The sequence of reading pressure and temperature as well as of performing the software compensation is
depicted in flow chart, Fig. 3 and Fig. 5.
First the WORD1 to WORD4 have to be read through the serial interface. This can be done once after reset of
the microcontroller that interfaces to the MS5534. Next the compensation coefficients C1 to C6 are extracted
using Bit-wise logical- and shift-operations (refer to Fig. 4 for the Bit-pattern of word 1 to word 4).
For the pressure measurement the microcontroller has to read the 16 Bit values for pressure (D1) and
temperature (D2) via the serial interface in a loop (for instance every second). Then, the compensated pressure
is calculated out of D1, D2 and C1 to C6 according to the algorithm in Fig. 3 (possibly using quadratic
temperature compensation according to Fig. 5). All calculations can be performed with signed 16-Bit variables.
Results of multiplications may be up to 32-Bit long (+sign). In the flow according to Fig. 3 each multiplication is
followed by a division. This division can be performed by Bit-wise shifting (divisors are to the power of 2). It is
ensured that the results of these divisions are less than 65536 (16-Bit).
For the timing of signals to read out WORD1 to WORD4, D1, and D2 please refer to the paragraph “Serial
Interface”.
Measurement principle
For both pressure and temperature measurement the same ADC is used (sigma delta converter):
• for the pressure measurement, the differential output voltage from the pressure sensor is converted
• for the temperature measurement, the sensor bridge resistor is sensed and converted
During both measurements the sensor will only be switched on for a very short time in order to reduce power
consumption. As both, the bridge bias and the reference voltage for the ADC are derived from VDD, the
digital output data is independent of the supply voltage. The A/D converter has been optimized to work in the
linear range (numeric values in range [5,000:37,000]).
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Basic equations:
System
initialisation
Start
Example:
Read calibration data (factory calibrated) from
PROM of MS5534
Word1 = 50426
Word2 = 9504
Word3 = 48029
Word4 = 55028
Word1, Word2, Word3 and Word4 (4x16 Bit)
Convert calibration data into coefficients:
(see bit pattern of Word1-Word4)
Pressure and temperature measurement
C1: Pressure sensitivity
C2: Pressure offset
C3: Temperature coefficient of pressure sensitivity
C4: Temperature coefficient of pressure offset
C5: Reference Temperature
C6: Temperature coefficient of the temperature
(15 Bit)
(12 Bit)
(10 Bit)
(10 Bit)
(11 Bit)
(6 Bit)
SENST1
OFFT1
TCS
TCO
Tref
TEMPSENS
C1 = 25213
C2 = 1908
C3 = 859
C4 = 750
C5 = 148
C6 =
32
Read digital pressure value from MS5534A
D1 (16 Bit)
D1 = 17000
Read digital temperature value from MS5534A
D2 (16 Bit)
D2 = 22500
Calculate calibration temperature
UT1=8*C5+20224
Calculate actual temperature
Difference between actual temperature and reference
temperature:
dT = D2 - UT1
Actual temperature in °C:
dT(D2) = D2 - Tref
dT
TEMP(D2)=20°+dT(D2)*TEMPSENS
TEMP = 287
= 28.7 °C
OFF(D2)=OFFT1+TCO*dT(D2)
OFF
SENS(D2)=SENST1+TCS*dT(D2)
SENS = 50705
10
TEMP = (200 + dT*(C6+50)/2 )/10
= 1092
Calculate temperature compensated pressure
Offset at actual temperature:
OFF = C2*4 + ((C4-512)*dT)/212
Sensitivity at actual temperature:
= 7695
SENS = C1 + (C3*dT)/210 + 24576
X = (SENS * (D1-7168))/214 - OFF
X
= 22732
P
= 96037
= 960.37 mbar
Temperature compensated pressure:
P = X*100/25 + 250*100 (0.01mbar resolution)
P = X*10/25 + 250*10
P(D1,D2)=D1*SENS(D2)-OFF(D2)
(0.1mbar resolution)
Display pressure and temperature value
Fig. 3: Flow chart for pressure/temperature reading and software compensation.
Notes:
1. Readings of D2 can be done less frequently, but the display will be less stable in this case
2. For a stable display of 0.1mbar resolution, it is recommended to display the average of 8 subsequent
pressure values.
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C1 (15 Bit)
C5/I
1 Bit
Word 1
DB14
DB13
DB12
DB11
DB10
DB9
DB8
DB7
DB6
DB5
DB4
DB3
C5/II (10 Bit)
Word 2
DB9
DB8
DB7
DB6
DB5
DB4
DB9
DB8
DB7
DB6
DB5
DB4
DB3
DB2
DB1
DB0
DB5
DB4
DB9
DB8
DB7
DB6
DB5
DB4
DB0
DB10
DB3
DB2
DB1
DB0
DB7
DB6
DB1
DB0
C2/I (6 Bit)
DB3
DB2
DB1
DB0
DB11
DB10
C3 (10 Bit)
Word 4
DB1
C6 (6 Bit)
C4 (10 Bit)
Word 3
DB2
DB9
DB8
C2/II (6-Bit)
DB3
DB2
DB1
DB0
DB5
DB4
DB3
DB2
Fig. 4: Arrangement (Bit-pattern) of calibration data in Word1 to Word4.
Second-order temperature compensation
In order to obtain full accuracy over the whole temperature range, it is recommended to compensate for the
non-linearity of the output of the temperature sensor. This can be achieved by the second-order temperature
calculation for D2<UT1, i.e. by replacing the block "Calculate actual temperature" in flow chart Fig. 3 by the
following sequence:
no
D2≥UT1?
yes
Calculate actual temperature
Calculate actual temperature
Difference between the actual temperature and reference
temperature:
Difference between the actual temperature and reference
temperature:
7
dT = D2 - UT1
7
dT = (D2 - UT1)- ((D2-UT1)/2 )((D2-UT1)/2 )/2
Actual temperature in °C
2
Actual temperature in °C
10
10
8
TEMP = (200 + dT*(C6+50)/2 +dT/2 )/10
TEMP = (200 + dT*(C6+50)/2 )/10
Fig. 5: Flow chart for calculating the temperature to the optimum accuracy. The value for dT thus obtained is
then used for the calculation of the temperature compensated pressure as shown in Fig.3.
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Serial interface
The MS5534 communicates with microprocessors and other digital systems via a 3-wire synchronous serial
interface as shown in Fig. 1. The SCLK (Serial Clock) signal initiates the communication and synchronizes the
data transfer with each Bit being sampled by the MS5534 on the rising edge of SCLK and each Bit being sent by
the MS5534 on the rising edge of SCLK. The data should thus be sampled by the microcontroller on the falling
edge of SCLK and sent to the MS5534 with the falling edge of SCLK. The SCLK-signal is generated by the
microprocessor’s system. The digital data provided by the MS5534 on the DOUT pin is either the conversion
result or the software calibration data. In addition the signal DOUT (Data Out) is also used to indicate the
conversion status (conversion-ready signal, see below). The selection of the output data is done by sending the
corresponding instruction on the pin DIN (Data Input).
Following is a list of possible output data instructions:
•
•
•
•
•
•
•
Conversion start for pressure measurement and ADC-data-out
Conversion start for temperature measurement and ADC-data-out
Calibration data read-out sequence for word 1
Calibration data read-out sequence for word 2
Calibration data read-out sequence for word 3
Calibration data read-out sequence for word 4
RESET sequence
“D1”
“D2”
(Figure 6a)
(Figure 6b)
(Figure 6c)
(Figure 6d)
(Figure 6c)
(Figure 6d)
(Figure 6e)
Every communication starts with an instruction sequence at pin DIN. Fig. 6 shows the timing diagrams for the
MS5534. The device does not need a ‘Chip select’ signal. Instead there is a Start Sequence (3-Bit high) before
each Setup Sequence and Stop Sequence (3-Bit low) after each Setup Sequence. The Setup Sequence consists
in 4-Bit that select a reading of pressure, temperature or calibration data. In case of pressure- (D1) or
temperature- (D2) reading the module acknowledges the start of a conversion by a low to high transition at pin
DOUT during the last bit of the Stop Sequence.
Two additional clocks at SCLK are required after the acknowledge signal. Then SCLK is to be held low by the
microcontroller until a high to low transition on DOUT indicates the end of the conversion.
This signal can be used to create an interrupt in the microcontroller. The microcontroller may now read out the
16-Bit word by giving another 17 clocks on the SLCK pin. It is possible to interrupt the data read-out sequence
with a hold of the SCLK signal.
It is important to always read out the last conversion result before starting a new conversion.
Conversion start for pressure measurement and ADC-data-out "D1":
end of conversion
start of conversion
conversion
(33ms)
ADC-data out MSB
DB7 DB6 DB5 DB4 DB3 DB2 DB1
DIN
DOUT SCLK
The RESET-sequence is special as its unique pattern is recognized by the module in any state. By consequence
it can be used to restart if synchronization between the microcontroller and the MS5534 has been lost. This
sequence is 21-Bit long. The DOUT signal might change during that sequence (see Fig. 6e).
It is thus recommended to send the RESET-Sequence before each Conversion Sequence to avoid
hanging up the protocol permanently in case of electrical interference.
ADC-data out LSB
DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
sequence: START+P-measurement
Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9
Start-bit
Setup-bits
Stop-bit
Fig. 6a: D1 acquisition sequence
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end of conversion
conversion
(33ms)
start of conversion
ADC-data out MSB
DB7 DB6 DB5 DB4 DB3 DB2 DB1
DIN
DOUT SCLK
Conversion start for temperature measurement and ADC-data-out "D2":
ADC-data out LSB
DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
sequence: START+T-measurement
Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9
Start-bit
Setup-bits
Stop-bit
DIN
DOUT SCLK
Fig. 6b: D2 acquisition sequence
Calibration data read out sequence for word 1/ word 3:
coefficient-data out MSB
DB7 DB6 DB5 DB4 DB3 DB2 DB1
coefficient-data out LSB
DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
sequence: coefficient read + address
Bit0 Bit1 Bit2
Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9 Bit10 Bit11
Stop-bit
Setup-bits
Start-bit
address word 1
address word 3
DIN
DOUT SCLK
Fig. 6c: W1, W3 reading sequence
Calibration data read out sequence for word 2/ word 4:
coefficient-data out MSB
DB7 DB6 DB5 DB4 DB3 DB2 DB1
coefficient-data out LSB
DB0 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
sequence: coefficient read + address
Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9 Bit10 Bit11
Setup-bits
Start-bit
Stop-bit
address word 2
address word 4
DIN
DOUT SCLK
Fig. 6d: W2, W4 reading sequence
RESET - sequence:
sequence: RESET
Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9 Bit10 Bit11Bit12 Bit13 Bit14 Bit15 Bit16 Bit17 Bit18 Bit19 Bit20
Fig. 6e: Reset sequence (21-Bit)
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APPLICATION INFORMATION
GENERAL
The idea for this combination of a sensor with a direct adapted integrated circuit is to save other external
components and to achieve very low power consumption. The main application field for this system includes
portable devices with battery supply, but its high accuracy and resolution make it also suited for industrial and
automotive applications. The possibility to compensate the sensor with a software allows the user to adapt it to
his particular application. Communication between the MS5534A and the widely available microcontrollers is
realized over an easy-to-use 3-wire serial interface. Customers may select which microcontroller system to be
used, and there are no specific standard interface cells required, which may be of interest for specially designed
4 Bit-microcontroller applications.
Storage of calibration data in the device will be done at module final test. Automatic test equipment is used to
perform tests under pressure and temperature and to calculate individual coefficients for every sensor, which
allows a highly accurate compensation.
Further, because the calibration data is stored in the MS5534A, the user can save additional external memory in
his microcontroller system (i.e. EEPROM).
The MS5534A is mounted on a ceramic substrate. SnPb connection pads ensure the soldering of the substrate
and automatic assembly. Standard surface mount techniques can be used (IR reflow soldering technique at
temperatures not exceeding 225° C for 30 sec is recommended). A dot on the ceramic substrate marks pad 1.
The silicon pressure transducer and the bonding wires are protected by a plastic cap on the standard version.
MS5534AP is factory protected against humidity by a silicone gel. Version MS5534AM carries a metal protection
cap filled with silicone gel for enhanced protection against humidity.
The package outline of the module allows the use of a flexible PCB to connect it. This can be important for
applications in watches and other special devices, and will also reduce mechanical stress on the device.
For applications subjected to mechanical shock, it is recommended to enhance the mechanical reliability of the
solder junctions by covering the rim or the corners of MS5534A's ceramic substrate with glue or glob top-like
material.
Particular care must be taken when connecting the device to power supply: A 47µF tantalum capacitor must be
placed as close as possible of the MS5534's VDD pin. This capacitor will stabilize the power supply during data
conversion and thus, provide the highest possible accuracy.
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ALTIMETER SYSTEM USING MS5534A
MS5534A is a circuit that can be used in connection with a microcontroller in mobile altimeter applications. It is
designed for low-voltage systems with a supply voltage of 3V, particularly in battery applications. The MS5534A is
optimised for low current consumption as the AD-converter clock (MCLK) can use the 32.768kHz frequency of a
standard watch crystal, which is supplied in most portable watch systems.
For applications in altimeter systems Intersema can deliver a simple formula to calculate the altitude, based on a
linear interpolation, where the number of interpolation points influences the accuracy of the formula.
VDD
MCLK
Input MUX
SENSOR
Digital
Interface
+IN
ADC
-IN
DIN
DOUT
dig.
Filter
SCLK
Memory
(PROM)
64 bits
Sensor
Interface IC
SGND
GND
Figure 7: Block diagram of MS5534A
Advantages of MS5534:
- easy layout (one side contact for flexible
PCB)
- better reliability
- reduced test time
- universal to use, less development time
- high compensation accuracy because of
individual sensor test
- lower price as a solution with sensor,
amplifier, AD-converter and external
parts
- easy-to-use 3 wire serial interface
APPLICATION EXAMPLES
3V-Battery
LCD-Display
VDD
XTAL1
32.768 kHz
MS5534
VDD
47uF
Tantal
XTAL2
Keypad
MCLK
DIN
DOUT
SCLK
GND
4/8bit-Microcontroller
VSS
EEPROM
optional
Figure 8: Demonstration of MS5534A in a mobile altimeter
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DEVICE PACKAGE OUTLINES
MS5534AP
1±0.28
9 + 0.15
-0
∅=7
top view
bottom view
max. 6
1.2
2.1
0.8
1±0.28
0.8
max. 7
1.75
0.925 1.27
9 + 0.15
-0
R 0.15
∅ 2.5
1.2
0.8
2.2 + 0.1
-0.05
1.5
max.1
0.635 ± 0.07
all measures
in mm
Fig. 9: Device package outlines of MS5534AP
MS5534AM
bottom view
max. 6
0.8
2.1
max. 7
1.75
0.925 1.27
9 + 0.15
-0
R 0.15
0.8
1.2
1±0.28
1±0.28
top view
9 + 0.15
-0
∅=7
∅=5
1.2
0.8
1.5
max.1
0.635 ± 0.07
3.7 + 0.1
-0.05
all measures
in mm
Fig. 10: Device package outlines of MS5534AM
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RECOMMENDED PAD LAYOUT
Pad layout for bottom side of MS5534A soldered onto printed circuit board
11.50
1.00
1.30
1.325
0.85
2.80
1.325
1.50
0.05
1.50
0.05
1.00
5
1.27
each pad
1.00
4
7.30
1.27
each pad:
6
3
2
6.30
All measures
in mm.
1.325
1.30
2.30
1
MS5534A
1.30
0.30
hole in board
0.70
1.00
Pad layout for top side of MS5534A soldered onto printed circuit board
11.50
2.40
2.90
1.90
1.70
2.40
3.10
2.20
each pad
3.675
1.00
2
1.27
1.00
1.27
each pad:
1
∅7.30==
3
4
5
All measures
in mm.
6
MS5534A
∅7.30mm hole in board
with phase 45° x 0.15
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ASSEMBLY
Soldering MS5534A
240
Temp. 225 +/- 5 °C
(240 C max.)
REFLOW
200
180
Time : 50 - 80 sec
160
120
PREHEAT
Temp. 150 +/- 10 C
Time
60 -120 sec.
Temperature [C]
80
40
0
0
60
120
180
240
300
360
Time [Seconds]
Figure 11: Recommended soldering profile
Solder Paste
The MS5534A is a ceramic device that requires special assembly considerations compared to the assembly of
SMD leaded components. The connecting pads are made of AgPd (Silver Palladium) pads. Like for other
ceramic devices the sensor must be soldered with Sn62Pb36Ag2 Solder paste. This solder paste contains 2% of
silver which avoids silver migration from the AgPd pad into the solder paste. The melting point of this paste is
slightly lower (179°C) than the the standard Sn63Pb37 solder paste.
DO NOT USE SN63PB37 Solder Paste for soldering MS5534A !
Soldering Quality
A good solder connection should look like shown on the photo to the below left forming a slight angle and filling
the via almost to the top. DO ALWAYS SOLDER BY REFLOW using the recommended reflow profile. Soldering
by hand will in most cases result in overheating of the device due to the good thermal conductivity of the
ceramic. It is recommended to optimize the profile attaching a thermocouple to the sensor. Too low temperature
will result in incomplete soldering resulting in a much less strong connection to the PCB as can be seen on the
photo below right. For prototyping purposes cables can be soldered to the solder bumps on the backside of the
sensor. The cable should be very thin to avoid lifting off the contact pad from the ceramic. Wire wrap cables will
normally do a good job.
Bad Solder Contact
Good Solder Contact
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Mechanical Stress
It is recommended to avoid mechanical stress on the PCB on which the sensor is mounted. The thickness of the
PCB should be not below 1.6mm. A thicker PCB is more stiff creating less stress on the soldering contacts. For
applications where mechanical stress cannot be avoided (for example ultrasound welding of the case or thin
PCB’s in watches) please fix the sensor with drops of low stress epoxy (for example Hysol FP-4401) at the
corners of the sensor as shown below.
Fixing with Globtop
increases mechanical
stability
Mounting
The MS5534A can be placed with automatic Pick&Place equipment using vacuum nozzles. It will not be
damaged by the vacuum. Due to the low stress assembly the sensor does not show pressure hysteresis effects.
Special care has to be taken to not touch the protective gel of the sensor during the assembly.
The MS5534A can be mounted with the cap down or the cap looking upwards. In both cases it is important to
solder all contact pads. The Pins PEN and PV shall be left open or connected to Vdd.
DO NOT CONNECT TO GND !
Solder at both sides to
increase mechanical
stability
Placement Cap down
(hole in PCB to fit cap)
Placement Cap up (rectangular
hole in PCB to fit Globtop)
Sealing with O-Ring
In products like outdoor watches the electronics must be protected against direct water or humidity. For those
products the MS5534-AM provides the possibility to seal with an O-Ring. The protective cap of the MS5534-AM
is made of special anticorrosive stainless steel with a polished surface. In addition to this the MS5534-AM is
filled with silicone gel covering the sensor and the bonding wires. The O-Ring (or O-Rings) shall be placed at the
outer diameter of the metal cap. This method avoids mechanical stress because the sensor can move in vertical
direction.
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Cleaning
The MS5534A has been manufactured under cleanroom conditions. Each device has been inspected for the
homogenity and the cleaningness of the silicone gel. It is therefore recommended to assemble the sensor under
class 10’000 or better conditions. Should this not be possible, it is recommended to protect the sensor opening
during assembly from entering particles and dust. To avoid cleaning of the PCB, solder paste of type “No-Clean”
shall be used.
CLEANING MIGHT DAMAGE THE SENSOR.
ESD Precautions
The electrical contacts except programming pads are protected against ESD according to 2KV HBM (human
body model). The programming pads are more sensitive due to the nature of the OTP programming cells that
store the calibration coefficients. The breakdown voltage of PEN and PV is 800V typical. It is therefore essential
to ground machines and personal properly during assembly and handling of the device. The MS5534A is
shipped in antistatic transport boxes. Any test adapters or production transport boxes used during the assembly
of the sensor shall be of an equivalent antistatic material.
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ORDERING INFORMATION
Product Code
MS5534AP
Product
Barometer Module with
plastic cap
MS5534AM
Barometer Module with
metal cap
Package
SMD hybrid with solder
paste, plastic protection
cap
SMD hybrid with solder
paste, metal protection
cap, silicon gel sensor
protection
Comments
standard version
Recommended
for outdoor products
FACTORY CONTACTS
Intersema Sensoric SA
Ch. Chapons-des-Prés 11
CH-2022 BEVAIX
Tel. (032) 847 9550
Tel. Int. +41 32 847 9550
Telefax +41 32 847 9569
e-mail: [email protected]
http://www.intersema.com
SWITZERLAND
LOCAL DISTRIBUTOR
Germany:
USA:
AMSYS GmbH
An der Fahrt 13
D-55124 Mainz
Tel. Int. +49 6131 46 98 75 55
Telefax +49 6131 46 98 75 66
http://www.amsys.de
Servoflo Cooperation
75 Allen Street
Lexington, MA 02421
Tel. Int. +1 781 862 9572
Telefax +1 781 862 9244
http://www.servoflo.com
NOTICE
Intersema reserves the right to make changes to the products contained in this data sheet in order to improve the design or performance
and to supply the best possible products. Intersema assumes no responsibility for the use of any circuits shown in this data sheet, conveys
no license under any patent or other rights unless otherwise specified in this data sheet, and makes no claim that the circuits are free from
patent infringement. Applications for any devices shown in this data sheet are for illustration only and Intersema makes no claim or
warranty that such applications will be suitable for the use specified without further testing or modification.
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