Power Thermistors Inrush Current Limiting Power Thermistor ST Series Inrush Current Limiters Description Littelfuse inrush current limiters (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 inrush current limiting power thermistor 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. Part Numbering System Dimensions ST 10 0 01 B Series B D Resistance @ 25C Base Value C A TINNED SOLDERABLE WIRE SEE CHART FOR LEAD DIAMETER Dimensions shown in inches. A B Max. Steady State Current (A) Multiplier, power of 10 PROTECTIVE COATING C No Significance Note: Not all combinations of Part Number codes are available. Contact Littelfuse for details. D A 0.310" B NOM .700" See Dim See Dim C MIN "D" "T" D 0.310" Max 0.700" Min See Dim "D" See Dim "T" INRUSH CURRENT LIMITING POWER THERMISTORS "T" ".900" MIN "D" 0.310" NOM TINNED SOLDERABLE WIRE SEE CHART FOR LEAD DIAMETER (c) 2018 Littelfuse, Inc. Revised: February 26, 2018 Specifications are subject to change without notice. PROTECTIVE COATING 1 littelfuse.com Power Thermistors Inrush Current Limiting Power Thermistor ST Series Inrush Current Limiters Specifications Part Number Resistance Ohms @25C *Resistance Tol. % @ 25C Imax Max. Steady State Current IMAX (A) Nominal Resistance @ Max. Current, RImax (Ohms) RImax Resis. @ Max. Current Ohms Lead Diameter Nominal (Inch) ST0R713B 0.7 25 13 0.025 0.025 0.04 ST1R005B 1 30 5 0.040 0.09 0.024 ST1R020B 1 15 20 0.030 0.015 0.04 ST1R030B 1 25 30 0.050 0.015 0.04 ST1R508B 1.5 20 8 0.040 0.6 0.032 ST2R018B 2 20 18 0.135 0.03 0.04 ST2R503B 2.5 20 3 0.070 0.15 0.032 ST2R507B 2.5 20 7 0.070 0.05 0.032 ST2R509B 2.5 20 9 0.060 0.04 0.032 ST2R510B 2.5 20 10 0.200 0.04 0.04 ST10001B 10 20 1 0.090 0.65 0.024 ST10003B 10 20 3 0.015 0.2 0.032 ST10005B 10 20 5 0.015 0.2 0.04 ST10006B 10 20 6 0.600 0.15 0.04 ST10010B 10 20 10 0.030 0.1 0.04 ST12001B 12 20 1 0.150 1.19 0.032 ST15004C 15 20 4 0.050 0.25 0.032 ST16002D 16 20 2 0.040 0.47 0.032 ST20001C 20 20 0.3 0.110 1 0.024 ST20002B 20 20 1.75 0.400 0.6 0.032 ST25002C 25 20 2 0.100 0.64 0.032 ST20100B 200 20 0.1 0.170 6.3 0.018 *Resistance tolerances of 1%, 2%, and 5% are available upon request (c) 2018 Littelfuse, Inc. Revised: February 26, 2018 Specifications are subject to change without notice. 2 littelfuse.com Power Thermistors Inrush Current Limiting Power Thermistor ST Series Inrush Current Limiters Specifications Part Number Resistance Ohms @25C *Resistance Tol. % @ 25C Imax Max. Steady State Current IMAX (A) Nominal Resistance @ Max. Current, RImax (Ohms) RImax Resis. @ Max. Current Ohms Temperature Lead Diameter Temperature Rating Coefficient Nominal (Inch) (C) (% / C) @ 25C ST2R515B 0.7 25 13 0.500 0.025 _ 0.04 _ ST4R005B 1 30 5 0.250 0.09 _ 0.024 _ ST5R002B 1 15 20 0.470 0.015 _ 0.04 _ ST5R004B 1 25 30 1.000 0.015 _ 0.04 _ ST5R005B 1.5 20 8 0.600 0.6 _ 0.032 _ ST7R004B 2 20 18 1.075 0.03 _ 0.04 _ ST8R001B 2.5 20 3 0.740 0.15 _ 0.032 _ ST8R003B 2.5 20 7 1.485 0.05 _ 0.032 _ ST8R006B 2.5 20 9 _ 0.04 -4.4 0.032 +300 (Max) ST30002B 10 20 1 0.280 0.65 _ 0.024 _ ST30003B 10 20 3 0.135 0.2 _ 0.032 _ ST33001B 10 20 5 0.650 0.2 _ 0.04 _ ST33001C 10 20 6 0.200 0.15 _ 0.04 _ ST33001D 10 20 10 0.200 0.1 _ 0.04 _ ST3R008B 12 20 1 0.150 1.19 _ 0.032 _ ST3R017B 15 20 4 0.100 0.25 _ 0.032 _ ST40002B 16 20 2 1.190 0.47 _ 0.032 _ ST5R006B 20 20 0.3 6.300 1 _ 0.024 _ ST5R007B 20 20 1.75 0.640 0.6 _ 0.032 _ ST5R014B 25 20 2 0.460 0.64 _ 0.032 _ ST5R008B 200 20 0.1 0.700 6.3 _ 0.018 _ * Resistance tolerances of 1%, 2%, and 5% are available upon request Disclaimer Notice - Information furnished is believed to be accurate and reliable. However, users should independently evaluate the suitability of and test each product selected for their own applications. Littelfuse products are not designed for, and may not be used in, all applications. Read complete Disclaimer Notice at: www.littelfuse.com/disclaimer-electronics (c) 2018 Littelfuse, Inc. Revised: February 26, 2018 Specifications are subject to change without notice. 3 littelfuse.com