MFP

Flameproof Power Metal Film Resistors MFP Series Welwyn Components • • • Smallest size for power rating Resistance range 0.1 ohms to 1M ohms Flameproof protection Electrical Data MFP1 Power rating at 70°C Resistance range Limiting element voltage TCR Resistance tolerance Standard values Thermal impedance Ambient temperature range °C/watt °C 120 -55 to 155 watts ohms volts ppm/°C % < 1 Ω: 300 1 Ω - 9.1 Ω: 200 ≥10 Ω: 50 1, 2, 5 E24 preferred 82 =1 Ω: 1.0 350 100 0R1 – 1M MFP2 2 1R0 – 1M Physical Data Dimensions (mm) & Weight (g) PCB mounting centres 10.2 18.4 Min. bend radius 0.6 1.2 Type MFP1 MFP2 L Max 6.2 10.0 D Max 2.5 4.0 f min 21.0 27.0 d nom 0.6 0.8 Wt.nom 0.3 0.55 d D L f Construction The resistance element is a precisely controlled thin film of metal alloy on a high purity ceramic core, protected by a cement coating applied so that terminations remain completely clear. This permits a well defined body length (clean lead to clean lead dimension L). Marking Resistors are colour coded with 4 or 5 bands depending on value and tolerance. IEC 62 colours are used. Solvent Resistance The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Terminations Material Strength Solder-coated copper wire. The terminations meet the requirements of IEC 68.2.21 Flammability The resistor coating will not burn or emit incandescent particles under any condition of applied temperature or power overload. Solderability The terminations meet the requirements of IEC 115-1, Clause 4.17.3.2 General Note Welwyn Components reserves the right to make changes in product specification without notice or liability. All information is subject to Welwyn’s own data and is considered accurate at time of going to print. A subsidiary of TT electronics plc Issue D · 03.06 © Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com 143 Flameproof Power Metal Film Resistors MFP Series Welwyn Components Performance Data Maximum Load at rated power : 1000 hours at 70°C Shelf life : 12 months at room temperature Derating from rated power at 70°C Climatic Climatic category Temperature rapid change Resistance to solder heat Voltage proof ∆R % ∆R % volts ∆R % ∆R % ∆R % ∆R % 5 2 zero at 155°C 3 50/155/56 0.5 0.5 500 min Application Notes 1. If the resistors are to dissipate full rated power, it is recommended that the terminations should not be soldered closer than 4mm from the body. 2. Due to operating temperature limitations imposed by some pcb materials, derating may be necessary. An estimate of the temperature rise to be expected can be calculated using the thermal impedance figures given under Electrical Data. 3. MFP resistors an also be supplied pre-formed. Packaging MFP resistors are normally supplied tape packed ready for loading onto automatic sequencing and insertion machines. The standard taping method and critical dimensions are shown in Figure 1. Component wires will not protrude beyond the outside edge of the tapes. Alternative packaging available by request. Lead Formed resistors can also be supplied. Standard options of Lancet, Radial and Goalpost forming are shown in lead Form Information section. Figure 1 5 f1 6 b f2 6 Body location f1 – f2 ≤ 1.4 mm Standard Quantities Per Package Type Ammo pack MFP1 5000 MFP2 2000 Type b (mm) MFP1 52 MFP2 68 © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com 144 Issue D · 03.06