How is an SMD sensor built?

Surface mount devices (SMD) are a type of sensor designed for easy placement on a printed circuit board.

An SMD is small and rectangular in shape. The metal component contact points are positioned on the two short edges of a ceramic body. These contact points are key to the overall performance of the sensor and the first step of the build. The connecting edges are placed on the ceramic body and then fired to ensure they are securely held in place. The internal connection between the contact point and the ceramic body is usually a nickel based layer, while the external connection is provided via a tin based layer allowing for ease of soldering.

In the next step, a thin metal (oxide) resistive film is deposited on top and the SMD is fired again. The length, thickness and materials used determine the resistance of the final SMD product.

Lastly, the resistive element is covered with multiple layers of protective coating. This provides specific insulation characteristics, offering protection from mechanical damage or exposure to contaminants, moisture and extreme temperatures, depending on the particular application (see applications for SMD).

Kamet offers you Pt100 and Pt1000 SMD’s. If you wish to know more about SMD sensor design related to your specific needs, please contact our experts. We are pleased to share our knowledge and experience in this field with you.

See also;

How and why are SMD sensors used on printed circuit boards?

When should you choose a Pt SMD over a NTC SMD?