TDK introduces surface-mount surge current limiter based on PTC technology

     The J404 developed by TDK Corporation is the first * surface-mount inrush current limiter (ICL) based on PTC (positive temperature coefficient) technology. The component (order number B59404J0170A062) is designed for applications with DC voltages up to 500 V and AC voltages up to 350 V and can be used to limit inrush current in applications such as DC busbars and charging devices in electric vehicles.

     With a very compact design of 13.5 x 10 x 11 mm (L x W x H), users can save up to 70% space and weight on their PCBS with this surface mount design. These products can be processed quickly on automated production lines. As a result, the new component is well suited for a wide range of industrial and automotive applications.

     The element enters a high resistance state with a reference temperature of +170°C, a heat capacity of 1J/K, and a thermal time constant of 100s. At room temperature, the resistance is 500 Ω, with a minimum value of 150 Ω. The J404 can turn off failures (short circuits) up to 100 times and perform up to 100,000 cycles while the capacitor is charged and discharged.

     Large DC bus capacitors in electric vehicle inverters or variable speed drives for industrial applications will have an instantaneous working state like a short circuit when switched on. This sudden high energy cannot damage the other components of the system, which also applies to the case of failure. At this time, the PTC thermistor provides this protection by heating itself with a high current and changing into a high resistance state for a very short time, thereby reducing the current to a safe level.