VRW37

High Voltage Thick Film Resistors VRW Series • VRW37 meets the requirements of BS / EN / IEC 60065 • High working voltage to 3.5kV in compact size • High ohmic range to 30M • High pulse load capability • Robust flameproof coating material • RoHS compliant Welwyn Components Electrical Data VRW25 Power rating at 70˚ C Resistance range Limiting element voltage Isolation voltage TCR Resistance Tolerance Standard Values Thermal Impedance Ambient temperature range ˚ C/watt ˚C 140 -55 to +155˚ C watts (Ohms) volts dc or ac peak volts ppm/˚ C % 0.25 100K to 30M 1600 700 200 1, 2, 5 E24 preferred 112 VRW37 0.5 100K to 10M 3500 Physical Data Type L Max 6.2 9.0 (Dimensions (mm) & Weight (g) f min 21 19.6 d Nom 0.6 0.8 PCB mount centres 10.2 12.7 Min bend radius 0.6 1.2 Wt. nom 0.3 0.5 d D D Max 2.5 3.7 VRW25 VRW37 L f Construction Resistive thick film material is applied to high-grade ceramic rods. Tin-plated steel caps are force fitted and the termination wires are welded to the caps. The value is obtained by a helical cut in the film and finally the resistor body is protected by a cement coating applied so that the terminations remain completely clear. Terminations Material: Strength: Solderability: Hot tin dipped copper wire The terminations meet the requirements of IEC 68.2.21 The terminations meet the requirements of IEC 115-1 Clause 4.17.3.2 Marking 1% tolerance resistors are colour coded with 5 bands. 2% and 5% tolerance have 4 bands. IEC62 colours are used. Marking The body protection and marking are resistant to all normal industrial cleaning solvents suitable for printed circuits. Flammability The resistor coating will not burn under any condition of applied temperature or power overload. 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 © 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 Issue D · 01.07 Issue C 07.06 70 High Voltage Thick Film Resistors SQP VRW Series Welwyn Components Performance Data Maximum Load at rated voltage (1000hrs at 70˚C) Derating from rated power at 70˚ C Overload (10 x 5s on,6.25 off at 6.25 x Pr not 2 x LEV) 2 x LEV) 5s at 45s x Pr not exceeding exceeding Damp heat steady state (56 days, 40˚C, Climatic sequence Climatic category Temperature rapid change Resistance to solder heat Vibration Voltage Proof R% R% R% volts 0.5 0.5 0.5 700 min 90% RH) R% R% R% 1 2 1.5 1.5 55/155/56 0.05 0.05 0.05 R% 1.5 zero at 155˚ C 0.15 0.1 0.2 Typical 0.4 Pulse Performance Performace 100 VRW25 Vmax (kV) 10 VRW37 1 0.01 0.1 1 Megaohms 10 100 Maximum peak voltage in accordance with “IEC 60065 chapter 14.1” 50 discharges from a 1nF capacitor charged to V max. 12 discharges/minute. Application Notes 1. Due to operating temperature limits imposed by some PCB materials, derating may be necessary. An estimate of the temperature rise to be expected at the center of the body can be calculated using the thermal impedance figures given under Electrical Data. 2. VRW resistors can be supplied with radial, goalpost or lancet pre-formed leads. The VRW37 is also available in an SMD format with Z formed leads and packed in blister tape. Consult Factory for details. Packaging Our standard packaging for VRW is taped and boxed. The critical dimensions are shown in Figure 1. The component wires will not protrude beyond the outside edge of the tapes. Alternative packaging is available by request. Pre-formed resistors are supplied loose packed in plastic bags or boxes. Figure 1 5 mm f1 6 mm f2 52mm Body location f1-f2 1.4mm 6 mm © 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 Issue B 07.06 Issue C · 01.07 71 High Voltage Thick Film Resistors SQP Series VRW Series Welwyn Components Ordering Procedure Example: VRW25 at 1.2 megohms and 5% tolerance in ammo pack box of 5000 pieces Model VRW25 – 1M2 J I Value (use IEC62 code) Tolerance (use IEC62 code) F 5% J 1% G 2% J 5% Packing I Ammo VRW25 VRW37 5000/box 25000/box 2500/box standard © 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 Issue C 07.06 Issue B ·· 01.07 71