Cement Coated Surface Mount Wirewound Resistors Welwyn Components WA80Z Series • • • • • • All welded construction Suitable for automatic pick and place Excellent pulse handling capability Fuses safely under fault conditions Competitive cost Performance equivalent to 2, 3 & 5W axial resistors Electrical Data WA83Z WA84Z WA85Z Power rating at 25˚C watts 2 3 5 Resistance range 0R015 to 6K8 ohms 0R05 to 900R 0R01 to 2K2 Limiting element voltage volts 50 100 150 Isolation voltage volts 250 350 500 TCR ≤1R0:350 >1R0:200 ppm/°C Resistance tolerance % ≥20R: 1, 2, 5, 10 <20R: 5, 10 Standard values E24 series preferred Ambient temperature range °C -55 to 155 Physical Data Dimensions (mm) Type W I L W H l w d WA83Z 13.4±0.2 3.6 max 6.25 max 9.0 max 4.5±0.6 0.8 nom WA84Z 18.7±0.2 5.2 max 6.9 max 14.5 max 6.5±0.6 0.8 nom WA85Z 18.7±0.2 7.0 max 7.9 max 16.5 max 6.5±0.6 0.8 nom H L w d Recommended Pad Sizes Dimensions (mm) Type B A B C D WA83Z 5.5 2.5 min 10 max 15 min WA84Z 7.5 min 2.5 min 15 max 20 min WA85Z 7.5 min 2.5 min 15 max 20 min C A D Construction A high purity ceramic substrate is assembled with interference fit end caps to which are welded the terminations. The resistive element is wound on the substrate and welded to the caps. Flameproof silicone cement coating is applied prior to marking with indelible ink and lead forming. 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. © Welwyn Components Limited · Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com A subsidiary of TT electronics plc Issue G · 03.06 Cement Coated Surface Mount Wirewound Resistors Welwyn Components WA80Z Series Marking Solvent Resistance WA83Z and WA84Z resistors R10 and above are marked with four colour bands in conformance with IEC62. Values below R10 are marked with three bands (two digits and tolerance); there is no multiplier band. WA85Z resistors are legendmarked “WA85” plus resistance value and tolerance in conformance with IEC62. 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 component overload. Performance Data Maximum Typical Load at rated power: 1000hrs @ 25 or 70°C ∆R% 5 +0.001Ω 3 Dry heat: 1000hrs @ 200°C ∆R% 5 +0.001Ω 3 Short term overload ∆R% 5 +0.001Ω Derating from rated power @ 25°C 1 Zero at 155˚C ∆R% Climatic 5 +0.001Ω 2 Climatic category 55/200/56 TRC & Vibration ∆R% 5 +0.001Ω 1 Robustness & solder heat ∆R% 5 +0.001Ω 1 Long term damp heat ∆R% 5 +0.001Ω 1 Temperature rise See Graph 1 Pulse handling See Graph 2 Note: Testing was performed on FR4 test boards measuring 50mm x 50mm, with 1oz/ft2 (300g/m2) copper pads. The track area close to each pad was 120mm2. If a lower grade of PCB or less track area is used, derating of the power may be necessary. Temperature Rise WA80Z Thermal Performance Graph 1 260 240 220 200 180 Temp Rise (K) 160 140 120 100 80 60 40 20 0 0 0.5 WA83Z Hot Spot 1 1.5 WA83Z Joint 2 2.5 Power (W) WA84Z Hot Spot 3 WA84Z Joint 3.5 4 WA85Z Hot Spot © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com 4.5 5 WA85Z Joint Issue G · 03.06 Cement Coated Surface Mount Wirewound Resistors Welwyn Components WA80Z Series Pulse Handling heatsinking by PCB tracks have no effect on energy ratings. If higher energy ratings than those shown are needed, it is normally possible to design a pulse withstand variant. The graph below shows the energy handling capability of CSM resistors for single short pulses (<100mS). For longer pulses of duration up to 5 Seconds, up to 5 times the rated power may be applied. Note that forced-air cooling and Graph 2 WA80Z Energy Capability Graph 100 Energy (Joules) 10 1 0.1 0.01 0.1 1 10 Value (Ohms) WA83Z Packaging CSM products are supply on standard carrier tape and 330mm diameter reels suitable for automatic pick and place machines. Carrier tape dimensions and standard reels quantities are given below. Dimensions (mm) Type Ao Bo Ko W P T Quantity Per reel WA83Z 5.3 13.9 6.3 24 12 0.4 750 WA84Z 7.3 19.2 7.1 32 12 0.4 750 WA85Z 7.4 19.2 8.2 32 12 0.4 650 ø 13mm Ao Ko P Bo ø 330mm W 100 WA84Z 1000 10000 WA85Z Ordering Procedure Specify type reference, value and tolerance as shown in this example of WA84Z at 1.5KOhms 5%: Type WA84Z 1K5 J Value (use IEC 62 code) Tolerance (use IEC 62 code) F G J K 1% 2% 5% 10% All other dimensions as per EIA481 standard 24mm / 32mm © Welwyn Components Limited Bedlington, Northumberland NE22 7AA, UK Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: [email protected] · Website: www.welwyn-tt.com Issue G · 03.06