The Superior series of EPCOS SMD limit temperature sensors from TDK based on PTCs are available in case sizes 0805, 0603, and 0402 and cover a temperature range from 70°C to 145°C. Compared with the standard series, the new components use a more homogeneous ceramic material, which improves reliability while permitting processing by reflow soldering. Thanks to these properties, the PTCs of the Superior series are qualified based on AEC-Q200, Rev. C and thus satisfy the rigorous requirements for use in automotive electronics.

PTC thermistors have a nonlinear characteristic: at low temperatures such as ambient, their resistance is low. As the temperature rises, their resistance jumps suddenly depending on the ceramic material used. This threshold value is also known as the reference or limit temperature.