Littelfuse ST5R007B

Littelfuse Surge Current Limiters (Power Thermistors) are specially formulated and processed NTC thermistors designed to suppress high inrush currents in switching power supplies and other applications where high initial startup currents are undesirable. Their unique design enables them to handle extremely high current and voltage levels. In typical power supply applications, inrush current limiting power thermistors are connected in series with filter capacitors. When initial voltage is applied, the device limits current to an acceptable level due to its relatively high resistance until the capacitor is fully charged. Thereafter, the device's resistance drops significantly, rendering the voltage drop across it negligible.