0.053 NOM 0.053 NOM Surface Mount Thermistors MELF Style Thermistor MM Series LL-31 MicroMELF Thermistors Description Littelfuse LL-31 MicroMELF style glass encapsulated surface mount thermistors are manufactured using super stable NTC chips which are hermetically sealed in a glass package. The result is a device which exhibits excellent long-term reliability and stability even when subjected to severe environmental or thermal conditions. Their uniform dimensions make them especially suitable for use with automatic insertion equipment. Options Non-standard Point matched at resistance values specified temperatures and tolerances Tape and Reel Packaging Dimensions Features High temperature Low cost capability to +220C B Excellent long-term Surface mountable stability TINNED Hermetically sealed DUMET A glass package CONTACT TABS C GLASS BODY Part Numbering System MM 10 3 E 1 K Dimensions shown in inches. A B C Series Resistance Tolerance A B C F = 1% 0.049 0.075 K = 10% Resistance 25C 0.049 0.075 0.053 0.004 0.008 Base Value No Significance 0.004 0.008 Nom Multiplier, power of 10 R-T Curve 3 Ex. 103 = 10 x 10 = 10,000 LL-31 SERIES Note: Not all combinations of Part Number codes are available. Contact Littelfuse for details. 0.075 0.008 TINNED DUMET 0.049 CONTACT TABS 0.004 GLASS BODY 2018 Littelfuse, Inc. Revised: February 26, 2018 1 littelfuse.com Specifications are subject to change without notice. Surface Mount Thermistors MELF Style Thermistor MM Series LL-31 MicroMELF Thermistors Specifications Thermal Temperature Dissipation Time Resistance *Resistance Accuracy Temperature Part R-T Coefficient Beta (K) Constant, Constant, Ohms Tol. % (C) Rating Number Curve (% / C) 0-50C Nominal Max. - 25C 25C 0-50C (C) 25C (mW/C) Still Air (seconds) MM222E1K 2186 10 0.5C E1 -3.82 3320 1 5 -55 to +220 MM302F1K 3000 10 0.5C F -3.86 3419 1 5 -55 to +220 MM502F1K 5000 10 0.5C F -3.86 3419 1 5 -55 to +220 3320 1 MM103E1K 10000 10 E1 -3.82 5 -55 to +220 MM103G1K 10000 10 G -4.03 3575 1 5 -55 to +220 MM103J1F 10000 1 J -4.4 3892 1 5 -55 to +220 MM103J1K 10000 10 J -4.4 3892 1 5 -55 to +220 MM153J1K 15000 10 J -4.4 3892 1 5 -55 to +220 MM203J1F 20000 1 J -4.4 3892 1 5 -55 to +220 MM203J1K 20000 10 0.5C J -4.4 3892 1 5 -55 to +220 MM104J1F 100000 1 J -4.4 3892 1 5 -55 to +220 MM104J1K 100000 10 J -4.4 3892 1 5 -55 to +220 MM104R1K 100000 10 R -4.68 4140 1 5 -55 to +220 MM254R1K 250000 10 0.5C R -4.68 4140 1 5 -55 to +220 *Resistance tolerances of 1%, 2%, and 5% are available upon request Packaging Packaging Option Packaging Code Standard Quantity Standard Tape and Reel -TR 2500 EIA-481 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 2018 Littelfuse, Inc. Revised: February 26, 2018 2 littelfuse.com Specifications are subject to change without notice.