Inrush Current Limiting Power Thermistors U.S. Sensor's inrush current limiting power thermistors are specially formulated and processed NTC thermistors suitable for suppressing high inrush currents in switching power supplies and other applications where the high initial starting currents are undesirable. Their unique design enables them to handle extremely high current and voltage levels. In a typical power supply application, the device is used in series with the filter capacitors. Upon application of the initial voltage, the device, due to its relatively high resistance, limits the current flow to an acceptable level until the capacitors are charged. Thereafter, the device decreases in resistance substantially to a level where the voltage drop across it is negligible. U.S. Sensor 1832 W. Collins Ave Orange, CA 92867 Tel: 800-777-6467 Tel: 714-639-1000 Fax: 714-639-1220 Email: sales@ussensor.com Maximum Steady State Current (Imax) For power thermistors, the INRUSH CURRENT LIMITING POWER maximum continuous steady THERMISTORS state current, either DC or RMS AC, which the device is capable of passing. The maximum steady state current for U.S. Sensor power thermistors is determined assuming a maximum operating ambient temperature of 65C. If a specific application requires ambient temperature operation above 65C, custom designed View Photo devices are available. Resistance At Maximum Current (RImax) For power thermistors, the approximate resistance of the device under maximum steady state current conditions. IN-RUSH CURRENT LIMITING POWER Part Number Ro Resistance @ 25C 20% Ohms Imax Max. Steady State Current (Amps) RImax Resis. @ Max. Current Ohms Dim. "D" (Max. Over Coating) Dim. "T" (Max. Over Coating) Lead (Dia. Nom.) ST1R020B ST1R030B ST2R018B ST2R503B ST2R507B ST2R509B ST2R510B ST2R515B ST5R002B ST5R005B ST5R007B ST7R004B ST10003B ST10005B ST10006B ST10010B ST20002B ST40002B 1.0 1.0 2.0 2.5 2.5 2.5 2.5 2.5 5.0 5.0 5.0 7.0 10.0 10.0 10.0 10.0 20.0 40.0 20 30 18 3 7 9 10 15 2 5 7 4 3 5 6 10 1.75 2 0.015 0.015 0.030 0.150 0.050 0.040 0.040 0.030 0.400 0.100 0.070 0.200 0.200 0.200 0.150 0.100 0.600 0.600 1.200 1.475 1.200 0.600 0.700 0.900 1.200 1.200 0.600 0.675 0.925 0.600 0.575 0.750 1.175 1.475 0.500 0.725 0.300 0.350 0.350 0.250 0.250 0.250 0.300 0.300 0.250 0.250 0.275 0.300 0.300 0.350 0.350 0.300 0.300 0.250 0.040 0.040 0.040 0.032 0.032 0.032 0.040 0.040 0.032 0.032 0.032 0.040 0.032 0.040 0.040 0.040 0.032 0.032 Note: All Dimensions are in Inches Product Guide Top^ Previous