Resistors MELF Make Possible Welwyn Components MELF RResistoresisstors WRM Series WRM Series High reliability High reliability Predictable pulse handling capability Predictable pulse handling capability Tolerances down to 0.1% Tolerances down to 0.1% TCR down to 5 ppm/C TCR down to 5 ppm/C All parts are Pb-free and comply with EU Directive 2011/65/EU (RoHS2) Electrical Data WRM 0102 WRM 0204 WRM 0207 Power rating at 70C watts 0.125 0.25 0.4 Resistance range ohms 4R7 - 110K R22 5M1 R22 10M Limiting element voltage volts 150 200 250 TCR ppm/C 50 5,1 0,1 5, 25, 50, 100 15, 25, 50, 100 Resistance tolerance % 1 0.1, 0.25, 0.5, 1.0, 2, 5 Standard values E24 & E96 Thermal impedance k/W 250 200 140 Ambient temperature range C -55 to +125 10 Insulation resistance ohms >10 Physical Data Dimensions (mm) and weight (g) L 1 Type L D D K Weight max max max min D D WRM 0102 0.01 1 2.2 1.35 1.3 0.3 WRM 0204 3.7 1.55 1.55 0.5 0.02 1 L K WRM 0207 6.1 2.4 2.4 0.5 0.08 Construction Terminations A metal film is deposited onto a high dissipation ceramic Material Plated steel cap. former to which tin plated teminating caps are fitted. Solderability The pure tin finish produces ageing free The resistor is adjusted to value by a helical cut in the film contacts on which low melting solders can and the body is protected by a lacquer coating. be used. Dipped area shall be covered with a smooth and bright solder coating after Marking 3 seconds immersion at 215C. Resistance values are colour coded with four bands, three indicating value and one indicating the multiplier. Solvent Resistance (Note this describes standard marking, but certain values The body protection and marking are resistant to all normal may still be supplied with the addition of a tolerance band industrial cleaning solvents suitable for printed circuit boards. following the multiplier.) General Note General Note TT Electronics reservWelwyn Componentses the right to mak reserves the righte changes in product specific to make changes in pration without notice or liability.oduct specification without notice or liability. All information is subject to Welwyns own data and is considered accurate at time of going to print. A subsidiary of All information is subject to TT Electronics own data and is considered accurate at time of going to print. www.ttelectronicsresistors.com TT electronics plc Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK TT Electronics plc Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com 01. 11 04.15MELF MELF Resistors Make Possible Resistors WRM Series Welwyn Components WRM Series TCR and Tolerance Range Type TCR Tolerance Reference 5% 2% 1.0% 0.5% 0.25% 0.1% 50ppm WRM0102 4R7 - 110K 100ppm R22 R91 50ppm 1R 5M1 10R 1M6 22R 332K 43R 332K 25ppm 4R7 - 500K 10R 500K 22R 402K 43R 332K WRM0204 15ppm 10R 221K 22R 221K 43R 221K 10ppm 22R 221K 43R 221K 05ppm 100R 100K 100R 100K R22 R91 100ppm 1R-10M WRM0207 25ppm 10R - 1M 10R 680K 51R1 - 330K 100R - 100K 15ppm 51R1 - 10K 100R - 10K 51R1 - 10K * TC 10ppm & 5ppm is specified over the temperature range -10C to +85C. Performance Data Test Results R/R 0204 & 0207: 10R - <75R 0102: 4R7 - 110K, 0204 & 0204 & 0207: 75R - 100K & >100K - 332K 0207: R22 - <10R & >332K - 10M Short time overload* 0.05% + 0.01 0.1% + 0.01 0.25% + 0.05 Bending test* 0.05% + 0.01 0.1% + 0.01 0.25% + 0.05 Resistance to soldering heat 0.05% + 0.01 0.1% + 0.01 0.25% + 0.05 Temperature rapid change 0.05% + 0.01 0.1% + 0.01 0.25% + 0.05 Endurance* Load life 1000h 0.25% + 0.05 0.25% + 0.05 0.5% + 0.05 8000 h 0.5% + 0.05 0.5% + 0.05 1.0% + 0.05 Climatic sequence* 0.25% + 0.05 0.5% + 0.05 1.0% + 0.05 Damp heat steady state* 0.25% + 0.05 0.5% + 0.05 1.0% + 0.05 Current noise < 0.05 V/V < 0.25 V/V < 3 V/V Solderability Dipped area shall be covered with a smooth and bright solder coating of at least 96% 6 Voltage coefficient < 0.5 . 10 /V Voltage proof No flashover or breakdown * Resistors to be mounted on a PC-board according to IEC 115-1, clause 4.27.1 General Note TT Electronics reserves the right to make changes in product specification without notice or liability. All information is subject to TT Electronics own data and is considered accurate at time of going to print. www.ttelectronicsresistors.com Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK TT Electronics plc Telephone: +44 (0) 1670 822181 Facsimile: +44 (0) 1670 829465 Email: info welwyn-tt.com Website: www.welwyn-tt.com 01.11 04.15