RTS stands for "Reflowable Thermal Switch". It was developed to protect highly integrated power semiconductors like MOSFETs, ICs, IGBTs, Triacs, SCRs, etc. from overheating. Before mechanical activation, the RTS can be mounted using conventional reflow soldering techniques with temperature profiles up to 260 °C.
After having the RTS reflow soldered on a PCB, mechanical activation arms the RTS for tripping at 210 °C. This activation can be done manually or by fully automated means. In contrast to electrical activation, the RTS activation status is clearly and immediately visible to the installer. Furthermore, the third additional contact required for electrical activation is thereby eliminated.
The new type of overtemperature protection shines with the smallest dimensions and highest load capacity. Operating currents up to 100 A at rated voltages of up to 60 VDC can be handled by the RTS, which is just 6.6 x 8.8 mm in size. Customer-specific variants are available with an integrated shunt or an additional overcurrent fuse. These further integrated functions are resulting in less space consumed on the printed circuit board. The Reflowable Thermal Switch meets the high reliability requirements of AEC-Q200 and MIL-STD.
Thermal runaway refers to the overheating of a power semiconductor due to a self-reinforcing, heat-producing process. The reasons for this are the ever increasing power density and the trend towards miniaturization of electronic circuits.
RTS protects power semiconductors not through a logic circuit but rather through basic laws of physics. In case of a thermal runaway, the RTS reliably interrupts the circuit precisely at the well-defined temperature.