Walsin Technology Corporation
Page 1 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
WF12H, WF08H, WF06H, WF04H
±0.5%
High precision chip resistors
Size 1206, 0805, 0603, 0402
Customer :
Approval No :
Issue Date :
Customer Approval :
Walsin Technology Corporation
Page 2 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
FEATURE
1. Small size and light weight
2. High reliability and stability
3. Reduced size of final equipment
4. High precision
5. Higher component and equipment reliability
APPLICATION
• Power supply
• PDA
• Digital meter
• Computer
• Palmtop computers
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. Consctruction of Chip-R
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QUICK REFERENCE DATA
Item General Specification
Series No. WF12H WF08H WF06H WF04H
Size code 1206 (3216) 0805 (2125) 0603 (1608) 0402 (1005)
Resistance Range 10Ω ~ 1MΩ ( E96+E24 series) Tolerance ±0.5%
TCR (ppm/°C) 10Ω≤ R ≤ 1MΩ ≤ ± 100 ppm/°C ≤ ± 200 ppm/°C
Max. dissipation at Tamb=70°C 1/4 W 1/8 W 1/10 W 1/16W
Max. Operation Voltage (DC or RMS) 200V 150V 50V 50V
Max. overload voltage (DC or RMS) 400V 300V 100V 100V
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. Non E96 series resistance upon requested.
DIMENSIONS
Part No WF12H WF08H WF06H WF04H
L 3.10 ± 0.1 2.0 ± 0.10 1.60 ± 0.10 1.00±0.05
W 1.60 ± 0.1 1.25 ± 0.10 0.80 ± 0.10 0.50±0.05
Tt 0.50 ± 0.2 0.40 ± 0.20 0.30 ± 0.10 0.20±0.10
Tb 0.45 ± 0.2 0.40 ± 0.20 0.30 ± 0.20 0.25±0.10
t 0.65 ± 0.15 0.5 ± 0.15 0.45 ± 0.15 0.35±0.05
MARKING
WFxxH ±0.5% has same marking rule as WRxx ±1%.
4-digits marking for 1206, 0805 size
Each resistor is marked with a four digits code on the protective coating to designate the nominal resistance
value. For values below 97Ω6 the R is used as a digit. For values of 100Ω or greater, the first 3 digits are
significant, the fourth digit indicates the number of multiple to follow.
Example
RESISTANCE 10Ω 12Ω 100Ω 6800Ω 47000Ω
4-digits marking 10R0 12R0 1000 6801 4702
3-digits marking for 0603 size
No marking code for 0402 size
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Page 4 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of
±0.5%. The values of the E24/E96 series are in accordance with “IEC publication 60063”.
Derating
The power that the resistor can dissipate depends on the operating temperature; see Fig.2
Figure 2. Maximum dissipation in percentage of rated power
As a function of the ambient temperature
MOUNTING
Due to their rectangular shapes and small tolerances, Su rface 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 one minute.
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 235°C during 2 seconds.
The test condition for no leaching is 260°C
for 60 seconds. Typical examples of
soldering processes that provide reliable
joints without any damage are given in Fig
3.
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Page 5 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
Fig 3. Infrared soldering p ro file for Chip Resistors
CATALOGUE NUMBERS
The resistors have a catalogue number starting with :
WF06 H 3742 B T _
Size code
WF12 : 1206
WF08 : 0805
WF06 : 0603
WF04 : 0402
Type code
H : High precision,
<1%, TCR>50ppm
Resistance code
E96 +E24:
3 significant digits followed
by no. of zeros
102Ω =1020
37.4KΩ =3742
220Ω =2200
Tolerance
B : ±0.1%
D : ±0.5%
Packaging code
T : 7” Reeled taping
Termination code
_ = SnPb base (“_”
means a blank)
L = Sn base (lead
free)
Reeled tape packaging : 8mm width paper taping 5000pcs per 7” reel for 1206/0805/0603, 10000pcs per 7” reel for
0402.
TEST AND REQUIREMENTS(JIS C 5201-1 : 1998)
TEST PROCEDURE REQUIREMENT
DC resistance
Clause 4.5
DC resistance values measured at the test voltages specified below :
<10Ω@0.1V, <100Ω@0.3V, <1KΩ@1.0V, <10KΩ@3V,
<100KΩ@10V, <1MΩ@25V, <10MΩ@30V
Within the specified tolerance
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) ; 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 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%+0.10Ω)
Resistance to
soldering
heat(R.S.H)
Clause 4.18
Un-mounted chips completely immersed for 10±1second in a solder bath at 270
℃±5ºC no visible damage
∆ R/R max. ±(1%+0.05Ω)
Solderability
Clause 4.17
Un-mounted chips completely immersed for 2±0.5second in a solder bath at
235℃±5℃ good tinning (>95% covered)
no visible damage
Leach Test
Clause 4.18
Un-mounted chips completely immersed for 60±1second in a solder bath at 260
℃±5℃ Ditto
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%+0.05Ω)
Load life
(endurance)
Clause 4.25
70±2ºC, 1000 hours, loaded with RCWV or Vmax,1.5 hours on and 0.5 hours
off ∆R/R max. ±(3%+0.1Ω)
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TEST PROCEDURE REQUIREMENT
Load life in Humidity
Clause 4.24
1000 hours, at rated continuous working voltage 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%+0.1Ω)
Bending strength
Clause 4.33
Resistors mounted on a 90mm glass epoxy resin PCB(FR4); bending : 3 mm,
once for 10 seconds ∆R/R max. ±(1%+0.05Ω)
Adhesion
Clause 4.32
Pressurizing force: 5N, Test time: 10±1sec. No remarkable damage or removal
of the terminations.
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Page 7 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
PACKAGING
Paper Tape specifications (unit :mm)
Series No. A B W F E
WF12H 3.60±0.20 2.00±0.20 8.00±0.30 3.50±0.2 1.75±0.10
WF08H 2.40±0.20 1.65±0.20 8.00±0.30 3.50±0.2 1.75±0.10
WF06H 1.90±0.20 1.10±0.20 8.00±0.30 3.50±0.2 1.75±0.10
WF04H 1.20±0.10 0.7±0.10 8.00±0.20 3.50±0.05 1.75±0.10
Series No. P1 P0 ΦD T
WF12H 4.00±0.10 4.00±0.10 0.65±0.1
WF08H 4.00±0.10 4.00±0.10 0.65±0.1
WF06H 4.00±0.10 4.00±0.10 0.65±0.1
WF04H 2.00±0.10 4.00±0.10
1.0 0.0
50.1 +
−
Φ
0.40±0.05
Reel dimensions
Symbol A B C D
(unit : mm) Φ178.0±2.0 Φ60.0±1.0 13.0±0.2 9.0±0.5
Taping quantity
Walsin Technology Corporation
Page 8 of 8 WFxxHD ±0.5% Version 09 Nov.-2006
- Chip resistors 5,000 pcs/reel for WF12H, WF08H, WF06H.
- Chip resistors 10,000 pcs/reel for WF04H.
