In what applications are SMD sensors used and why?

SMD (surface mount device) sensors are the solution for temperature measurement applications where the sensor needs to be incorporated onto a printed circuit board (PCB). See this FAQ for how and why SMD’s are used on PCB’s.

Our Pt100 SMD sensor range brings all the advantages of platinum temperature sensors to applications requiring a standardized electronic format that generally needs to be as small as possible. Some specific examples include:

• data loggers where a high mounting density is needed
• safety management and monitoring applications to prevent critical electronics overheating and being damaged (the SMD sensor’s fast thermal response rate is essential for accurate readings)
• ambient air temperature measurement and controls such as in HVAC applications
• electric vehicles power plugs and chargers where SMD sensors are often chosen because they are more compact than wired elements
• processing high voltages in power electronics where the SMD sensor protects onboard chips such as those converting high voltage from for example a battery to an e-motor
• smart home controls for humidity, air quality and temperature control
• hospital equipment such as in ventilators

In general, SMD’s offer easy high volume electronic integration while still maintaining all the advantages of thin film platinum sensors. That is to say they can withstand vibration while offering accuracy and excellent response time across a range of temperatures. SMD’s are competitively priced and are designed to suit high volume automated mounting.These characteristics make SMD’s very useful in the following industries:

• a wide range of electronics, especially where a high performance and accuracy are required. Such as automotive, aviation and medical.
• home appliances and equipment
• electric vehicles
• battery packs

How is an SMD sensor built?

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;

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