The SDP3x differential pressure sensor features excellent accuracy and long-term stability and has no zero-point drift. It is the perfect choice for high volume and cost-sensitive applications, where small size is essential. This application note gives advice and guidelines for engineers integrating an SDP3x sensor into their product, to make sure that the sensor can unfold its full performance after being placed in an application.
The world’s smallest differential pressure sensor SDP3x measures only 5mm x 8mm x 5mm, opening up new dimensions of integration and application possibilities. The sensor is based on the next generation of the CMOSens® chip, which is the heart of Sensirion’s new sensor platform for measuring differential pressure and mass flow. The small size offers new prospects for applications with differential pressure sensors. To ensure best performance it is important that a few simple recommendations are taken into account when designing a product using SDP3x. This
application note will give advice about how to design the manifold or flow channel in order to ensure a tight but stress-free connection with the sensor.
Sensor Connection
The sensor can be reflow soldered to a printed circuit board (PCB). Soldering guidelines and pin assignments can be found in the sensor’s datasheet. The three pins in the corners of the sensor will ensure correct placement on the PCB.
For the pressure connections there are various options:



The SDP3x is not designed to be used directly with tubes. Where tube connections are necessary, Sensirion
recommends using an adaptor piece (see above) or the use of other sensors with long ports from Sensirion’s
differential pressure portfolio.
Where tubes need to be used for sensor testing or during the product design phase, it is important to keep them as
short as possible (below 10 cm) and make sure to read the Application Note “Pressure drop in hose” in order to
calculate the measurement deviation caused by the tube.

The sealing can either be done radially, axially or by means of a gasket.




The SDP3x is a robust component. Although the soldering pad design is fully sufficient to fulfil its purpose as a device
fixation, special care needs to be taken since other mechanical parts are connected to the ports of the sensor and
therefore might induce peak stress to the sensor, e.g. when the device falls to the ground.
There are different ways to prevent excessive stress:




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