LTCC (Low Temperature Co-Fired Ceramic) has great potential in the field of sensors and transducers due to its thermal,
electrical and mechanical properties. The paper describes work concerning a capacitive pressure sensor realized on LTCC
with thick-film deposition technologies. A capacitive pressure sensor converts a change in the position of the conductive
plates to an electrical signal; for this a deformable diaphragm is used. In the presented case one electrode is bonded to the
deformable diaphragm (an edge-clamped, circular diaphragm) and the other electrode is fixed. The signal from the sensor is
processed by the AD7745 circuit. This circuit is a high resolution digital capacity-signal converter with high performances,
high linearity ±0.01% and very good accuracy ±4 fF. The circuit also encompasses a voltage reference and a temperature
sensor with a resolution of 0.1°C. The external connection is made through the I2C interface, using a signal control unit which
processes the signal and sends the information to an LCD (liquid crystal display) and/or to a computer which, in turn, records
the information for later use through the USB interface.
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