DA5541B_005.doc

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00005541766 ECN865

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).

MOUNTING

The MS5541B 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.

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!

SEALING WITH O-RING

In products like diving computers the electronics must be protected against direct water or humidity. For those

products the MS5541B provides the possibility to seal with an O-ring. The protective cap of the MS5541B is

made of special anticorrosive stainless steel with a polished surface. In addition to this the MS5541B 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.

CLEANING

The MS5541B 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 2KV HBM (human

body model). The PV programming pads are more sensitive due to the nature of the OTP programming cells

that store the calibration coefficients. The breakdown voltage of PV is 1kV. It is therefore essential to ground

machines and personal properly during assembly and handling of the device. The MS5541B 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.