ST1R020B Littelfuse

PPoowweer Tr Thheerrmmiissttororss 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 No Significance B D Resistance 25C Max. Steady State Base Value Current (A) C A Multiplier, power of 10 TINNED SOLDERABLE WIRE PROTECTIVE SEE CHART FOR LEAD DIAMETER COATING Note: Not all combinations of Part Number codes are available. Contact Littelfuse for details. Dimensions shown in inches. A B C D A 0.31B 0 .700 See DimC See Dim D NOM MIN D T 0.310 0.700 See Dim See Dim Max Min D T INRUSH CURRENT LIMITING POWER THERMISTORS T .900 MIN D 0.310 NOM TINNED SOLDERABLE WIRE SEE CHART FOR LEAD DIAMETER PROTECTIVE COATING 2018 Littelfuse, Inc. Revised: February 26, 2018 1 littelfuse.com Specifications are subject to change without notice. Power Thermistors Inrush Current Limiting Power Thermistor ST Series Inrush Current Limiters Specifications Resistance *Resistance Imax Max. Steady Nominal Resistance RImax Resis. Lead Diameter Part Ohms Tol. % State Current I Max. Current, Max. Nominal MAX Number 25C 25C (A) RImax (Ohms) Current Ohms (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 2018 Littelfuse, Inc. Revised: February 26, 2018 2 littelfuse.com Specifications are subject to change without notice.