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WF12H, WF08H, WF06H, WF04H
±
±±
±0.1%
High precision chip resistors
Size 1206, 0805, 0603, 0402
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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
6. RoHS compliant, Lead free products.
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 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 ( 2012 ) 0603 ( 1608 ) 0402 ( 1005 )
Resistance Range 10Ω ~ 1MΩ ( E96+E24 series) Tolerance ±0.1%
TCR (ppm/°C) 1MΩ ≥ R ≥ 10Ω ≤ ± 100 ≤ ± 100
Max. dissipation at T
amb
=70°C 1/4 W 1/8 W 1/10 W 1/16 W
Max. Operation Voltage (DC or RMS) 200V 150V 50V 50V
Max. overload voltage (DC or RMS) 400V 300V 100V 100V
Climatic category 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(unit : mm)
Part No WF12H WF08H WF06H WF04H
L 3.10 ± 0.10
2.00 ± 0.10
1.60 ± 0.10
1.00±0.05
W 1.60 ± 0.10
1.25 ± 0.10
0.80 ± 0.10
0.50±0.05
Tt 0.50 ± 0.20
0.40 ± 0.20
0.30 ± 0.10
0.20±0.10
Tb 0.45 ± 0.20
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
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MARKING
3-digits marking for 0603 size
WFxxH ±0.1% 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
No marking code for 0402 size
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of ±0.1%. 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, 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.
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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 235°C during 2 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
CATALOGUE NUMBERS
The resistors have a catalogue number starting with :
WF06 H 3742 B T L
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
B : Bulk
Termination code
L = Sn base (lead
free)
Taping quantity
Reeled tape packaging : 8mm width paper taping 5,000pcs per reel for WF12H, WF08H, WF06H.
8mm width paper taping
10,000pcs per reel for WF04H.
Bulk packaging : 5000pcs per polybag
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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) ; 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. ±(0.25%+0.05Ω)
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
∆R/R max. ±(0.25%+0.05Ω)
Solderability
Clause 4.17
Un-mounted chips completely immersed for 2±0.5 second in a SAC
solder bath at 235℃±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. ±(0.25%+0.05Ω)
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. ±(2%+0.1Ω)
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. ±(2%+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. ±(0.25%+0.05Ω)
Adhesion
Clause 4.32
Pressurizing force: 5N, Test time: 10±1sec. No remarkable damage or
removal of the terminations.
Insulation Resistance
Clause 4.6
Apply the maximum overload voltage (DC) for 1minute R≧10GΩ
Dielectric Withstand
Voltage
Clause 4.7
Apply the maximum overload voltage (AC) for 1 minute No breakdown or flashover
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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
1.0 0.0
50.1
+
−
Φ
0.65±0.1
WF08H 4.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
0.65±0.1
WF06H 4.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
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
