Walsin Technology Corporation
Page 1 of 7 WW18X Version 10 Jun.-2009
WW18X
±
±±
±1%, ±
±±
±5%
Low ohmic power chip resistors
Size 1218
Customer :
Approval No :
Issue Date :
Customer Approval :
Walsin Technology Corporation
Page 2 of 7 WW18X Version 10 Jun.-2009
FEATURE
1. High power rating and compact size
2. High reliability and stability
3. Reduced size of final equipment
4. Lead free termination upon customer requested
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 a Lead-tin or Tin (lead free) alloy.
Fig 1. Construction of a 1218 Chip-R
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Page 3 of 7 WW18X Version 10 Jun.-2009
QUICK REFERENCE DATA
Item General Specification
Series No. WW18X
Size code 1218(3248)
Resistance Tolerance ±5% (E24) ±1% (E96)
Resistance Range 0.02Ω ~ 0.91Ω 0.02Ω ~ 0.976Ω
TCR (ppm/°C)
0.02Ω ≤ Rn < 0.05Ω
0.05Ω ≤ Rn < 0.10Ω
0.10Ω ≤ Rn < 0.50Ω
0.50Ω ≤ Rn < 1Ω
≤ 1500 ppm/°C
≤ 1000 ppm/°C
≤ 500 ppm/°C
≤ 300 ppm/°C
Max. dissipation at T
amb
=70°C 1 W
Max. Operation Voltage (DC or
RMS) 200V
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
ValueResistancePower RatedRCWV ×=
or Max. RCWV listed above, whichever is lower.
3. Tolerance of TCR=±200ppm/°C
4. 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
Symbol Dimensions (mm)
L 3.05±0.15
W 4.60±0.20
T 0.55±0.10
Tt 0.45±0.25
Tb 0.50±0.25
MARKING
Each resistor is marked with a four-digit code on the protective coating to designate the nominal
resistance value.
Example:
R010 = 0.01Ω ,R510 = 0.51Ω
Walsin Technology Corporation
Page 4 of 7 WW18X Version 10 Jun.-2009
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of
±5% & ±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 260°C 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 245°C during 3 seconds. The test
condition for no leaching is 260°C 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 WW18X
Walsin Technology Corporation
Page 5 of 7 WW18X Version 10 Jun.-2009
CATALOGUE NUMBERS
The resistors have a catalogue number starting with .
WW18 X R100 J T L
Size code
WW18: 1218
Type code
X : Thick
film,
Resistance code – 4 digits
R100 = 0.1 OHM
R976 = 0.976 OHM
Tolerance
J: ±
±±
± 5%
F: ±
±±
± 1%
Packaging code
T: 10” Reeled
taping
Termination
code
L = Sn base
(lead free)
Reeled tape packaging : paper taping 3000pcs per 10” reel.
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: 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.
Walsin Technology Corporation
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TEST PROCEDURE REQUIREMENT
Temperature Coefficient
of Resistance(T.C.R)
Clause 4.8
Natural resistance change per change in degree centigrade.
( )
6
121
12 10×
−
−
ttR RR
(ppm/°C) t
1
: 20°C+5°C-1°C
R
1
: Resistance at reference temperature
R
2
: Resistance at test temperature
Refer to
“QUICK REFERENCE DATA”
Short time overload
(S.T.O.L) Clause 4.13 Permanent resistance change after a 5second application of a voltage 2.5 times
RCWV or the maximum overload voltage specified in the above list, whichever
is less. ∆R/R max. ±(2%+0.005Ω)
Resistance to soldering
heat(R.S.H)
IEC 60068-2-58: 2004
Un-mounted chips completely immersed for 10±1second in a SAC solder bath
at 255℃±5ºC no visible damage
∆ R/R max. ±(1%+0.005Ω)
Solderability
IEC 60068-2-58: 2004
Un-mounted chips completely immersed for 3±0.3second in a SAC solder bath
at 245℃±5℃ good tinning (>95% covered)
no visible damage
Temperature cycling
Clause 4.19 30 minutes at -55°C±3°C, 2~3 minutes at 20°C+5°C-1°C, 30 minutes at
+155°C±3°C, 2~3 minutes at 20°C+5°C-1°C, total 5 continuous cycles no visible damage
∆R/R max. ±(1%+0.005Ω)
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 ∆R/R max. ±(3%+0.005Ω)
Load life in Humidity
Clause 4.24 1000 +48/-0 hours, loaded with RCWV or Vmax in humidity chamber controller
at 40°C±2°C and 90~95% relative humidity, 1.5hours on and 0.5 hours off ∆R/R max. ±(3%+0.005Ω)
Bending strength
Clause 4.33 Resistors mounted on a 90mm glass epoxy resin PCB(FR4); bending : 2 mm,
once for 10 seconds ∆R/R max. ±(1%+0.005Ω)
Adhesion
Clause 4.32 Pressurizing force: 5N, Test time: 10±1sec. No remarkable damage or
removal of the terminations
Insulation Resistance
JISC5201-1:1998
Clause 4.6
Apply the maximum overload voltage (DC) for 1minutes R≧10GΩ
Dielectric Withstand
Voltage
JISC5201-1:1998
Clause 4.7
Apply the maximum overload voltage (AC) for 1 minutes
No breakdown or flashover
Walsin Technology Corporation
Page 7 of 7 WW18X Version 10 Jun.-2009
PACKAGING
Plastic Tape specifications (unit :mm)
Symbol Ao Bo W F E
Dimensions 3.55±0.30 4.90±0.20 12.00±0.20 5.50±0.05 1.75±0.10
Symbol P1 P0 ΦD T
Dimensions 8.00±0.10 8.00±0.10
1.0 0.0
55.1
+
−
Φ
1.30±0.20
Reel dimensions
Symbol A B C D
(unit : mm) Φ178.0±2.0 Φ60.0±1.0 13.0±0.2 14.0±0.2
Taping quantity
- Chip resistors 3,000 pcs per reel.
