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MS5534B (RoHS*)

BAROMETER MODULE

o 10 - 1100 mbar absolute pressure range
o 6 coefficients for software compensation stored
on-chip
o Piezoresistive silicon micromachined sensor
o Integrated miniature pressure sensor 9 x 9 mm
o 15 Bit ADC
o 3-wire serial interface
o 1 system clock line (32.768 kHz)
o Low voltage and low power consumption
o RoHS-compatible & Pb-free*
DESCRIPTION
The MS5534B 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. MS5534B is a low power, 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.
Compared to the previous version (MS5534A) the temperature range has been improved (-40 to +125° as well
C)
as the pressure range (measurement down to 10 mbar). Other improvements concern the ESD sensitivity, current
consumption and converter accuracy.

FEATURES

APPLICATIONS

o Supply voltage 2.2 V to 3.6 V
o Low supply current
o -40° to +125° operation temperature
C
C
o No external components required

o Mobile altimeter / barometer systems
o W eather control systems
o Adventure or multi-mode watches
o GPS receivers

BLOCK DIAGRAM
VDD
MCLK

Input MUX
SENSOR

Digital
Interface

+IN

-IN

ADC

Sensor
Interface IC
SGND

DIN
DOUT

dig.
Filter

SCLK

Memory
(PROM)
64 bits

GND

Fig. 1: Block diagram 5534B.
*

The European RoHS directive 2002/95/EC (Restriction of the use of certain Hazardous Substances in electrical and electronic equipment)
bans the use of lead, mercury, cadmium, hexavalent chromium and polybrominated biphenyls (PBB) or polybrominated diphenyl ethers
(PBDE).

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PIN CONFIGURATION

Fig. 2: Pin configuration of MS5534B.
Pin Name

Pin

Type

Function

GND
SCLK
DOUT
DIN
MCLK
VDD
PEN (1)
PV (1)

1
2
3
4
5
6
7
8

G
I
O
I
I
P
I
N

Ground
Serial data clock
Data output
Data input
Master clock (32.768 kHz)
Positive supply voltage
Programming enable
Negative programming voltage

NOTES
1) Pin 7 (PEN) and PIN 8 (PV) are only used by the manufacturer for calibration purposes and should not be
connected.

ABSOLUTE MAXIMUM RATINGS
Parameter
Supply voltage
Storage temperature
Overpressure

Symbol
VDD
TS
P

Conditions
o

Ta = 25 C
o

Ta = 25 C

Min

Max

Unit

Notes

-0.3
-40

4
+125
10

V
C
bar

1
2

o

NOTES
1) Storage and operation in an environment of dry and non-corrosive gases.
2) The MS5534BM is qualified referring to the ISO Standard 2281 and can withstand an absolute pressure of 11
bar in salt water or 100 m water respectively.

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RECOMMENDED OPERATING CONDITIONS
(Ta = 25° VDD = 3.0 V unless noted otherwise)
C,

Parameter
Operating pressure range
Supply voltage
Supply current,
average (1)
during conversion (2)
standby (no conversion)
Current consumption into
MCLK (3)
Operating temperature
range
Conversion time
External clock signal (4)

Symbol

Conditions

Typ.

2.2
VDD = 3.0 V

3.0
4
1

-40
MCLK = 32.768 kHz

MCLK

0.1

uA
mA
uA
uA
°
C
ms

1100

MCLK = 32.768 kHz

tconv

3.6

mbar
abs.
V

35

VDD

T

Unit

+125

10

Iavg
Isc
Iss

Max

0.5

p

30.000

35.000

kHz

50/50

60/40

%

500

SCLK

32.768

40/60

Duty cycle of MCLK
Serial data clock

Min.

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 MS5534B.
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 2 ms.
3) This value can be reduced by switching off MCLK while MS5534B 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.

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ELECTRICAL CHARACTERISTICS
DIGITAL INPUTS
(T = -40° .. 125° VDD = 2.2 V .. 3.6 V)
C
C,

Parameter

Symbol

Conditions

Min

Typ

Max

Unit

Input High Voltage

VIH

80% VDD

100% VDD

V

Input Low Voltage

VIL

0% VDD

20% VDD

V

Signal Rise Time

tr

200

ns

Signal Fall Time

tf

200

ns

DIGITAL OUTPUTS
(T = -40° .. 125° VDD = 2.2 V .. 3.6 V)
C
C,

Parameter

Symbol

Conditions

Min

Output High Voltage

VOH

Isource = 0.6 mA

Output Low Voltage

VOL

Isink = 0.6 mA

Typ

Max

Unit

75% VDD

100% VDD

V

0% VDD

20% VDD

V

Signal Rise Time

tr

200

ns

Signal Fall Time

tf

200

ns

AD-CONVERTER
(T = -40° .. 125° VDD = 2.2 V .. 3.6 V)
C
C,

Parameter

Symbol

Conditions

Min

Resolution

INL

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Max

15

Linear Range
Conversion Time

Typ

0
MCLK = 32.768
kHz
Within linear range

Unit
Bit

February 28th, 2005

LSB

35
-4

40000

ms

+4

LSB

4

PRESSURE OUTPUT CHARACTERISTICS
W ith the calibration data stored in the interface IC of the MS5534B the following characteristics can be achieved:
(VDD = 3.0 V unless noted otherwise)

Parameter

Conditions

Min

Resolution
Absolute Pressure Accuracy
Relative Pressure Accuracy
Error over Temperature

Long-term Stability
Maximum Error over Supply
Voltage

Typ

Max

p = 750 .. 1100 mbar
Ta = 25°
C
p = 750 .. 1100 mbar
Ta = 25°
C
T = 0 .. +70°
C
p = const.
T = -40 .. +85°
C
p = const.
T = -40 .. +125°
C
p = const.
12 months
VDD = 2.2 .. 3.6 V
p = const.

Notes

mbar

0.1

Unit

1

-1.5

+1.5

mbar

2

-0.5

+0.5

mbar

3

-2

+2

mbar

4

?2

mbar

4

?3

mbar

4

-1

mbar

5

-1.6

+1.6

mbar

NOTES
1) A stable pressure reading of the given resolution requires taking the average of 2 to 4 subsequent pressure
values due to noise of the ADC.
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 "FUNCTION " . See next section for
typical operating curves.
5) 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.

(VDD = 3.0 V unless noted otherwise)

Parameter

Conditions

Accuracy
Maximum Error over Supply
Voltage

T = 20°
C

Max

Unit

0.005

Resolution

Min

0.015

°
C

-0.8

0.8

°
C

?2

T = -40 .. +125°
C
VDD = 2.2 .. 3.6 V

Typ

-0.2

°
C
+ 0.2

Notes

1

°
C

NOTES
1) With the second-order temperature compensation as described in Section "FUNCTION " . See next section for
typical operating curves.

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TYPICAL PERFORMANCE CURVES
ADC-value D1 vs Pressure (typical)
22000

20000

ADC-value (LSB)

18000

16000
Temp. -40°
C
Temp. 25°
C
Temp. 125°
C

14000

12000

10000

8000

6000
0

100

200

300

400

500

600

700

800

900

1000

1100

95

110

125

Pressure (mbar)

ADC-value D2 vs Temperature (typical)
42000
40000
38000
36000

ADC-value (LSB)

34000
32000
30000
28000
26000
24000
22000
20000
18000
-40

-25

-10

5

20

35

50

65

80

Temperature (°
C)

Absolute pressure accuracy after calibration (typical)
4
+125°
C
3

+85°C
+70°C

Pressure error (mbar)

2

+25°C

C

1

-40°
C

0

-1

-2

-3

-4
0

100

200

300

400

500

600

700

800

900

1000

1100

Pressure (mbar)

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Accuracy vs temperature (typical)
14
13
12
11
10
Temperature error (°C)

9
8

Temperature error
(standard
compensation)

7
6
5

Temperature error
(2nd order
compensation)

4
3
2
1
0
-1
-2
-40

-25

-10

5

20

35

50

65

80

95

110

125

Temperature (°
C)

Pressure error (mbar)

Accuracy vs temperature (typical)
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
-8

Perror (1000,1st order)
Perror (1000,2nd order)
Perror(800,1st order)
Perror(800, 2nd order)
Perror(100, 1st order)
Perror(100,2nd order)

-40

-25

-10

5

20

35

50

65

80

95

110

125

Temperature (°
C)

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Pressure error vs supply voltage (typical)
0.8

0.6

0.4

Pressure error (mbar)

0.2

0
2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

-0.2

Press. 100mbar
Press. 700mbar
Press. 1100mbar

-0.4

-0.6

-0.8

-1
Voltage (V)

Temperature error (25° vs supply voltage (typical)
C)
0.15

0.1

Temperature error (°
C)

0.05

0

2.2

2.4

2.6

2.8

3

3.2

3.4

3.6

-0.05

-0.1

-0.15

-0.2

Voltage (V)

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FUNCTION
GENERAL
The MS5534B consists of a piezoresistive sensor and a sensor interface IC. The main function of the MS5534B is
to convert the uncompensated analogue 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.
o measured pressure (16-Bit)
o 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.
D1
D2

Sensor

Word1..4

Pressure

Calculation
in external
microcontroller

Temperaturere

For both pressure and temperature measurement the same ADC is used (sigma delta converter):
o for the pressure measurement, the differential output voltage from the pressure sensor is converted
o 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.
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 64-Bit
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 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 MS5534B. 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 Word1 to Word4).
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".

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Basic equations:

System
initialisation

Start

Example:

Read calibration data (factory calibrated) from
PROM of MS5534B

W ord1 = 50426
W ord2 = 9504
W ord3 = 48029
W ord4 = 55028

W ord1, Word2, Word3 and Word4 (4x16 Bit)

Convert calibration data into coefficients:
(see bit pattern of Word1-Word4)
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
(12
(10
(10
(11
(6

Bit)
Bit)
Bit)
Bit)
Bit)
Bit)

SENST1
OFFT1
TCS
TCO
Tref
TEMPSENS

C1 = 25213
C2 = 1908
C3 = 859
C4 = 750
C5 = 148
C6 =
32

Pressure and temperature measurement

(Refer to application note AN509 for limits of coefficients and
calculated results)

Read digital pressure value from MS5534B
D1 (16 Bit)

D1 = 17000

Read digital temperature value from MS5534B
D2 (16 Bit)

D2 = 22500

Calculate calibration temperature
UT1 = 8*C5+20224

Calculate actual temperature
Difference between actual temperature and reference
temperature:

dT

TEMP = 287
= 28.7 °
C

OFF(D2) = OFFT1+TCO*dT(D2)

OFF

SENS(D2) = SENST1+TCS*dT(D2)

Actual temperature:

dT(D2) = D2 - Tref
TEMP(D2) = 20°+dT(D2)*TEMPSENS

dT = D2 - UT1

SENS = 50705

10

TEMP = 200 + dT*(C6+50)/2 (0.1°C resolution)

= 1092

Calculate temperature compensated pressure
Offset at actual temperature:

OFF = C2*4 + ((C4-512)*dT)/2

12

Sensitivity at actual temperature:
10

SENS = C1 + (C3*dT)/2 + 24576

X

14

X = (SENS * (D1-7168))/2 - OFF
Temperature compensated pressure:
5

P = X*10/2 + 250*10

= 7695

(0.1mbar resolution)

P(D1,D2) = D1*SENS(D2)-OFF(D2)

= 22732

P

= 9603
= 960.3 mbar

Display pressure and temperature value

Fig. 3: Flow chart for pressure and 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 0.1 mbar resolution, it is recommended to display the average of 8 subsequent
pressure values.
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10

C1 (15 Bit)

W ord1

DB14

DB13

DB12

DB11

DB10

DB9

DB8

DB7

C5/I

1 Bit
DB6

DB5

DB4

DB3

C5/II (10 Bit)
W ord2

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

DB1

DB0

DB7

DB6

DB1

DB2

DB0

C2/I (6 Bit)
DB3

DB2

DB1

DB0

DB11

DB10

C3 (10 Bit)
W ord4

DB1

C6 (6 Bit)

C4 (10 Bit)
W ord3

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 best 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 correcting the calculated
temperature and pressure by a second order correction factor. The second-order factors are calculated as
follows:

200 <= TEMP <= 450

TEMP &amp; lt; 200
yes

TEMP &amp; gt; 450
yes

yes

No correction

Low Temperatures

High Temperatures

T2 = 11*(C6+24)*(200 - TEMP)*(200 - TEMP) / 220

T2 = 0

T2 = 3*(C6+24)*(450 - TEMP)*(450 - TEMP) / 220

P2 = 3 *T2 * (P - 3500)/214

P2 = 0

P2 = T2 * (P - 10000)/213

Calculate pressure and temperature
TEMP = TEMP - T2
P = P - P2

Fig. 5: Flow chart for calculating the temperature and pressure to the optimum accuracy.

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SERIAL INTERFACE
The MS5534B 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 synchronises the data
transfer with each Bit being sampled by the MS5534B on the rising edge of SCLK and each Bit being sent by the
MS5534B 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 MS5534B with the falling edge of SCLK. The SCLK-signal is generated by the
microprocessor's system. The digital data provided by the MS5534B 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:

o
o
o
o
o
o
o

Conversion start for pressure measurement and ADC-data-out
Conversion start for temperature measurement and ADC-data-out
Calibration data read-out sequence for Word1
Calibration data read-out sequence for Word2
Calibration data read-out sequence for Word3
Calibration data read-out sequence for Word4
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
MS5534B. 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 16Bit word by giving another 17 clocks on the SLCK pin. It is possible to interrupt the data READOUT sequence with
a hold of the SCLK signal. It is important to always read out the last conversion result before starting a new
conversion.
The RESET sequence is special as its unique pattern is recognised by the module in any state. By consequence it
can be used to restart if synchronisation between the microcontroller and the MS5534B has been lost. This
sequence is 21-Bit long. The DOUT signal might change during that sequence (see Fig. 6e). It is recommended
to send the RESET sequence before each CONVERSION sequence to avoid hanging up the protocol
permanently in case of electrical interference.

DOUT SCLK

Conversion start for pressure measurement and ADC-data-out &quot; D1 &quot; :
end of conversion

start of conversion

conversion
(33ms)

ADC-data out MSB

DIN

DB7 DB6 DB5 DB4 DB3 DB2 DB1

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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DOUT SCLK

Conversion start for temperature measurement and ADC-data-out &quot; D2 &quot; :
end of conversion

conversion
(33ms)

start of conversion

ADC-data out MSB

DIN

DB7 DB6 DB5 DB4 DB3 DB2 DB1

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

Fig. 6b: D2 ACQUISITION sequence.

DIN

DOUT SCLK

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
Setup-bits

Start-bit

Stop-bit
address word 1
address word 3

Fig. 6c: Word1, Word3 READING sequence.

DIN

DOUT SCLK

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

Fig. 6d: W2, W4 READING sequence.

DIN

DOUT SCLK

RESET - sequence:

sequence: RESET
Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7 Bit8 Bit9 Bit10 Bit11Bit12 Bit13 Bit14 Bit15 Bit16 Bit17Bit18 Bit19 Bit20

Fig. 6e: RESET sequence (21-Bit).

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APPLICATION INFORMATION
GENERAL
The advantage of combining a pressure sensor with a directly adapted integrated circuit is to save other external
components and to achieve a 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 MS5534B and the widely available microcontrollers is realised
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 Bitmicrocontroller applications.

CALIBRATION
The MS5534B is factory calibrated. The calibration data is stored inside the 64-Bit PROM memory.

SOLDERING
Please refer to the application note AN808 for all soldering issues.

HUMIDITY, WATER PROTECTION
The silicon pressure transducer and the bonding wires are protected by a plastic protection cap on the standard
version. MS5534BP is factory protected against humidity by a silicone gel.
The version MS5534BM carries a metal protection cap filled with silicone gel for enhanced protection against
humidity. The properties of this gel ensure function of the sensor even when in direct water contact. This feature
can be useful for waterproof watches or other applications, where direct water contact cannot be avoided.
Nevertheless the user should avoid drying of hard materials like for example salt particles on the silicone gel
surface. In this case it is better to rinse with clean water afterwards. Special care has to be taken to not
mechanically damage the gel. Damaged gel could lead to air entrapment and consequently to unstable sensor
signal, especially if the damage is close to the sensor surface.
The metal protection cap is fabricated of special anticorrosive stainless steel in order to avoid any corrosive battery
effects inside the final product. The MS5534BM was qualified referring to the ISO Standard 2281 and can
withstand a pressure of 11 bar in salt water. The concentration of the see water used for the qualification is 41 g of
see salt for 1 litre of DI water.
For underwater operations as specified in ISO Standard 2281 it is important to seal the sensor with a rubber O-ring
around the metal cap. Any salt water coming to the contact side (ceramic and pads) of the sensor could lead to
permanent damage. Especially for &quot; water-resistant 100 m &quot; watches it is recommended to provide a stable
mechanical pusher from the backside of the sensor. Otherwise the overpressure might push the sensor backwards
and even bend the electronic board on which the sensor is mounted.

LIGHT SENSITIVITY
The MS5534B is sensitive to sunlight, especially to infrared light sources. This is due to the strong photo effect of
silicon. As the effect is reversible there will be no damage, but the user has to take care that in the final product the
sensor cannot be exposed to direct light during operation. This can be achieved for instance by placing mechanical
parts with holes in such that light cannot pass.

CONNECTION TO PCB
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 MS5534B' ceramic substrate with glue or Globtop-like
s
material.

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DECOUPLING CAPACITOR
Particular care must be taken when connecting the device to power supply. A 47 uF tantalum capacitor must be
placed as close as possible of the MS5534B' VDD pin. This capacitor will stabilise the power supply during data
s
conversion and thus, provide the highest possible accuracy.

APPLICATION EXAMPLE: ALTIMETER SYSTEM USING MS5534B
MS5534B 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 3 V, particularly in battery applications. The MS5534B is
optimised for low current consumption as the AD-converter clock (MCLK) can use the 32.768 kHz 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.

3V-Battery

LCD-Display

VDD
32.768 kHz

XTAL1

MS5534
VDD

47uF
Tantal

XTAL2

Keypad

MCLK
DIN
DOUT
SCLK
GND

4/8bit-Microcontroller
VSS

EEPROM
optional

Figure 7: Demonstration of MS5534B in a mobile altimeter.

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DEVICE PACKAGE OUTLINES

Fig. 8: Device package outlines of MS5534BP.

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DEVICE PACKAGE OUTLINES (CONT.)

Fig. 9: Device package outlines of MS5534BM.

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RECOMMENDED PAD LAYOUT
Pad layout for bottom side of MS5534B soldered onto printed circuit board

Pad layout for top side of MS5534B soldered onto printed circuit board

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ASSEMBLY
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 1.6 mm. 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 MS5534B can be placed with automatic Pick &amp; 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 MS5534B 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 the Pins
PEN and PV 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 MS5534BM provides the possibility to seal with an O-ring. The protective cap of the MS5534BM is
made of special anticorrosive stainless steel with a polished surface. In addition to this the MS5534BM 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 MS5534B has been manufactured under cleanroom conditions. Each device has been inspected for the
homogeneity and the cleanness 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 2 kV HBM (human body
model). The PV programming pad is more sensitive due to the nature of the OTP programming cells that store the
calibration coefficients. The breakdown voltage of PV is 1 kV. It is therefore essential to ground machines and
personal properly during assembly and handling of the device. The MS5534B 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

Product

Art.-Nr.

Package

Comments

MS5534-BP

Barometer Module
with plastic cap

325534000

SMD hybrid with solder paste,
plastic protection cap

Standard version

MS5534-BM

Barometer Module
with metal cap

325534001

SMD hybrid with solder paste,
metal protection cap, silicon
gel sensor protection

Recommended
for outdoor products

FACTORY CONTACTS
Intersema Sensoric SA
Ch. Chapons-des-Prés 11
CH-2022 BEVAIX
SWITZERLAND

Tel. 032 847 9550
Tel. Int. +41 32 847 9550
Telefax +41 32 847 9569
e-mail:
http://www.intersema.ch

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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