Approval sheet WF25H, WF20H 0.1%, 0.5% Thick Film Power High Precision Resistors Size 2512, 2010 *Contents in this sheet are subject to change without prior notice. Page 1 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet FEATURE 1. High power rating and compact size 2. High reliability and stability 3. Reduced size of final equipment 4. High precision of resistance APPLICATION * Power supply * PDA * Digital meter * Computer * Automotives * Battery charger * DC-DC power converter DESCRIPTION The resistors are constructed in a high grade ceramic body (aluminum oxide). Internal metal electrodes are added at each end and connected by a resistive paste that is applied to the top surface of the substrate. The composition of the paste is adjusted to give the approximate resistance required and the value is trimmed to nominated value within tolerance which controlled by laser trimming of this resistive layer. The resistive layer is covered with a protective coat. Finally, the two external end terminations are added. For ease of soldering the outer layer of these end terminations is Tin (lead free) alloy. Fig 1. Construction of Chip-R Page 2 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet QUICK REFERENCE DATA Item General Specification Series No. WF25H WF20H Size code 2512 ( 6432 ) 2010 ( 5025 ) 0.5% ; 0.1% (E24+E96) Resistance Tolerance Resistance Range TCR (ppm/C) 1 ~ 10M, 1 Rn 10 200 ppm/C 10 < Rn 10M 100 ppm/C Max. dissipation at Tamb=70C 1W 0.5W Max. Operation Voltage (DC or RMS) 250V 200V Max. Overload Voltage (DC or RMS) 500V 400V Climatic category (IEC 60068) 55/155/56 Note : 1. This is the maximum voltage that may be continuously supplied to the resistor element, see "IEC publication 60115-8" 2. Max. Operation Voltage : So called RCWV (Rated Continuous Working Voltage) is determined by RCWV = Rated Power x Resistance Value or Max. RCWV listed above, whichever is lower. MECHANICAL DATA(unit : mm) Symbol 2512 2010 L 6.400.20 5.000.20 W 3.200.20 2.500.20 T 0.600.10 0.550.10 Tt 0.650.25 0.650.25 Tb 0.900.25 0.600.25 MARKING Each resistor is marked with a four-digit code on the protective coating to designate the nominal resistance value. Example: 1R00 = 1 1001 = 1000 Page 3 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet FUNCTIONAL DESCRIPTION Product characterization Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of 0.5% & 0.1%. The values of the E24/E96 series are in accordance with "IEC publication 60063". Derating curve The power that the resistor can dissipate depends on the operating temperature; see Fig.2 MOUNTING Due to their rectangular shapes and small tolerances, Surface Mountable Resistors are suitable for handling by automatic placement systems. Chip placement can be on ceramic substrates and printed-circuit boards (PCBs). Electrical connection to the circuit is by individual soldering condition. The end terminations guarantee a reliable contact. SOLDERING CONDITION The robust construction of chip resistors allows them to be completely immersed in a solder bath of 260C for 10 seconds. Therefore, it is possible to mount Surface Mount Resistors on one side of a PCB and other discrete components on the reverse (mixed PCBs). Surface Mount Resistors are tested for solderability at 235C during 2 seconds. The test condition for no leaching is 260C for 30 seconds. Typical examples of soldering processes that provide reliable joints without any damage are given in Fig 3. Fig 3. Infrared soldering profile for Chip Resistors Page 4 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet CATALOGUE NUMBERS The resistors have a catalogue number starting with : WF25 H 1000 B T L Size code Type code Resistance code Tolerance Packaging code Termination code WF25 : 2512 H : Thick film, B : 0.1% T : 7" Reel taping L = Sn base WF20 : 2010 High precision E24+E96 : 3 significant digits followed by no. of zeros 102 =1020 37.4K =3742 D : 0.5% (lead free) TEST AND REQUIREMENTS(JIS C 5201-1 : 1998) Essentially all tests are carried out according to the schedule of IEC publication 115-8, category LCT/UCT/56 (rated temperature range : Lower Category Temperature, Upper Category Temperature; damp heat, long term, 56 days). The testing also meets the requirements specified by EIA, EIAJ and JIS. The tests are carried out in accordance with IEC publication 68, "Recommended basic climatic and mechanical robustness testing procedure for electronic components" and under standard atmospheric conditions according to IEC 60068-1, subclause 5.3. Unless otherwise specified, the following value supplied : Temperature: 15C to 35C. Relative humidity: 45% to 75%. Air pressure: 86kPa to 106 kPa (860 mbar to 1060 mbar). All soldering tests are performed with midly activated flux. TEST DC resistance Clause 4.5 PROCEDURE DC resistance values measured at the test voltages Within the specified tolerance specified below : <10@0.1V, <10K@3V, <10M@30V Temperature Coefficient of Resistance ( TCR ) Clause 4.8 REQUIREMENT <100@0.3V, <100K@10V, <1K@1.0V, <1M@25V, Natural resistance change per change in degree Test temperature -55 ~ +155C centigrade. 1 Rn < 9.76, 300 ppm/C R2 - R1 x 106 R1 (t2 - t1 ) (ppm/C) 10 Rn < 1M, 1M Rn < 10M, 200 ppm/C 300 ppm/C R1 : Resistance at reference temperature R2 : Resistance at test temperature t1 : 20C+5C-1C Page 5 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet TEST Short time overload ( STOL ) Clause 4.13 Resistance to soldering heat PROCEDURE REQUIREMENT Permanent resistance change after a 5second application of a R/R max. (1%+0.05) voltage 2.5 times RCWV or the maximum overload voltage specified in the above list, whichever is less. Un-mounted chips 101 seconds, in a SAC solder bath at no visible damage 2605C R/R max. (1%+0.05) Clause 4.17 Solderability Clause 4.18 Temperature cycling Clause 4.19 Un-mounted chips completely immersed for 20.5 sec. in a good tinning (>95% covered) SAC solder bath at 2355C no visible damage 1. 30 minutes at -55C3C, no visible damage 2. 2~3 minutes at 20C+5C-1C, R/R max. (1%+0.05) 3. 30 minutes at +1553C, 4. 2~3 minutes at 20C+5C-1C, Total 5 continuous cycles Load life (endurance) 1000 +48/-0 hours, loaded with RCWV or Vmax controller 702C,1.5 hours on and 0.5 hours off in chamber R/R max. (3%+0.1) Clause 4.25 Load life in Humidity Clause 4.24 Bending and Termination strength 1000 +48/-0 hours, loaded with RCWV or Vmax in humidity R/R max. (3%+0.1) chamber controller at 40C2C and 90~95% relative humidity, 1.5hours on and 0.5 hours off Resistors mounted on a 90mm glass epoxy resin PCB(FR4); R/R max. (1%+0.05) bending : 2 mm, once for 10 seconds Pulling test : 500grams Clause 4.33 Insulation Apply the maximum overload voltage (DC) for 1minutes R10G Resistance Clause 4.6 Dielectric Withstand Apply the maximum overload voltage (AC) for 1 minutes Voltage No breakdown or flashover Clause 4.7 Page 6 of 7 ASC_WF25-20H_V05 Oct.-2011 Approval sheet PACKAGING Plastic tape specifications (unit :mm) Type A B W F E 2512 6.900.20 3.600.20 12.000.30 5.500.1 1.750.10 2010 5.500.20 2.800.20 12.000.30 5.500.1 1.750.10 Type P1 P0 D T 2512 4.000.10 4.000.10 1.50 +-00..10 Max. 1.2 2010 4.000.10 4.000.10 1.50 +-00..10 Max. 1.2 Reel dimensions Symbol A B C D (unit : mm) 178.02.0 60.01.0 13.00.2 14.00.2 Taping quantity - Chip resistors 4,000 pcs per reel. Page 7 of 7 ASC_WF25-20H_V05 Oct.-2011