WW25N WALSIN | Alldatasheet
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Page 1 of 7 ASC_WW25N_V16 NOV - 2018 WW25N 1%, 5%, 2W Ultra low ohm power chip resistors Size 2512 (6432) Metal Current Sensing Type RoHS Exemption free and Halogen free *Contents in this sheet are subject to change without prior notice.
Page 2 of 7 ASC_WW25N_V16 NOV - 2018 FEATURE 1. Ultra low and stable TCR performance 2. High power rating and compact size 3. High reliability and stability 4. Reduced size of final equipment 5. RoHS compliant and Lead free. 6. Inductance below 1nH APPLICATION Power supply PDA Digital meter Computer Automotives Battery charger DC-DC power converter
DESCRIPTION
The resistors are constructed in a high grade low resistive metal body. The resistive layer is covered with a protective coat and printed a resistance marking code over it . Finally, the two external end terminations are added. For ease of soldering the outer layer of these end terminations is a tin (lead-free) alloy. Fig 1. Construction of Chip-R
Page 3 of 7 ASC_WW25N_V16 NOV - 2018 QUICK REFERENCE DATA Item General Specification Series No. WW25N Size code 2512 ( 6432 ) Resistance Tolerance 5%, 1% TCR (ppm/C) ±70 ppm/C Max. dissipation at Tamb=70C 2 W Max. Operation current (DC or RMS) SQRT ( Power / Resistance ) Climatic category (IEC 60068) 55/155/56 Note : 1. Resistance value will be changed by soldering condition and design of soldering pad, please design products in consideration of this change of resistance value. MECHANICAL DATA FOOT PRINT Unit: mm W D L WW25N 3.70 1.60 7.60 Symbol R001, R002 R003 ~ R100 R010
Page 4 of 7 ASC_WW25N_V16 NOV - 2018 MARKING Each resistor is marked with a four -digit code on the protective coating to designate the nominal resistance value. R005 = 5 mΩ R020 = 20mΩ R020 R020 = 20mΩ FUNCTIONAL DESCRIPTION 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.
Page 5 of 7 ASC_WW25N_V16 NOV - 2018 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 discr ete 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 260 C for 30 seconds. Typical examples of soldering processes that provide reliable joints wit hout any damage are given in Fig 3. Fig 3. Infrared soldering profile for Chip Resistors WW25 CATALOGUE NUMBERS The resistors have a catalogue number starting with . WW25 N R005 J T L Size code WW25 : 2512 Type code N : 2W Sensing type Resistance code R is first digit followed by 3 significant digits. 0.010 = R010 0.005 = R005 Tolerance J : 5% F : 1% Packaging code T : 7” reeled in tape Termination code L = Sn base (lead free) Reeled tape packaging : 12mm width plastic emboss taping 4,000pcs per reel.
Page 6 of 7 ASC_WW25N_V16 NOV - 2018 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 compo nents" and under standard atmospheric conditions according to IEC 60068-1, subclause 5.3. Unless otherwise specified, the following value supplied : Temperature: 15°C to 35°C. 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 PROCEDURE REQUIREMENT Temperature Coefficient of Resistance(T.C.R) Clause 4.8 Natural resistance change per change in degree centigrade. 121 12 10 ttR RR (ppm/C) t1 : 20°C+5°C-1°C R1 : Resistance at reference temperature R2 : Resistance at test temperature Refer to “QUICK REFERENCE DATA” Short time overload (S.T.O.L) Clause 4.13 Permanent resistance change a fter a 5second application of 5 times rated power no visible damage Resistance to soldering heat(R.S.H) Clause 4.18 Un-mounted chips completely immersed for 10±1second in a SAC solder bath at 260℃±5ºC no visible damage Solderability Clause 4.17 Un-mounted chips complete ly immersed for 5±0.5second in a SAC solder bath at 235℃±5℃ good tinning (>95% covered) no visible damage Temperature cycling Clause 4.19 30 minutes at -55C3C, 2~3 minutes at 20°C+5°C-1°C, 30 minutes at +155 C3C, 2~3 minutes at 20°C+5°C-1°C, total 5 continuous cycles no visible damage Load life (endurance) Clause 4.25 1000 +48/-0 hours, loaded with RCWV or Vmax in chamber controller 70±2ºC, 1.5 hours on and 0.5 hours off no visible damage Load life in Humidity Clause 4.24 1000 +48/-0 hours, loaded with RCWV or Vmax in humidity chamber controller at 40 C2C and 90~95% relative humidity, 1.5hours on and 0.5 hours off no visible damage Adhesion Clause 4.32 Pressurizing force: 5N, Test time: 10±1sec. No remarkable damage or removal of the terminations
Page 7 of 7 ASC_WW25N_V16 NOV - 2018 PACKAGING Plastic Tape specifications (unit :mm) Symbol A B W F E Symbol P1 P0 D T Dimensions 4.00±0.10 4.00±0.10 1.0 0.050.1 Max. 1.2 Reel dimensions Symbol A B C D Taping quantity - Chip resistors 4,000 pcs per reel.