MS5534C Datasheet, PDF (14/21 Pages) Intersema Sensoric SA – BAROMETER MODULE

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 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 software allows the user to adapt it to his
particular application. Communication between the MS5534C 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 Bit-
microcontroller applications.
CALIBRATION
The MS5534C 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 version MS5534CM 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 MS5534CM was qualified referring to the ISO Standard 2281 and
can withstand a pressure of 11 bar in salt water. The concentration of the sea 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 "water-resistant 100 m" 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 MS5534C 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 MS5534C's ceramic substrate with glue or Globtop-like
material.
DA5534C_003.doc
June 16th, 2008
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0005534C1175 ECN1118