Approval sheet
Page 1 of 6 ASC_WFxxH_V02 Sep - 2011
WF12H, WF08H, WF06H, WF04H
±
±±
±0.5%, ±
±±
±0.1%
Thick film high precision chip resistors
Size 1206, 0805, 0603, 0402
*Contents in this sheet are subject to change without prior notice.
Approval sheet
Page 2 of 6 ASC_WFxxH_V02 Sep - 2011
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. Construction of Chip-R
Approval sheet
Page 3 of 6 ASC_WFxxH_V02 Sep - 2011
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)
Resistance Tolerance ±0.5%, ±0.1%
TCR (ppm/°C) 10Ω≤ R ≤ 1MΩ ≤ ± 100 ppm/°C
Max. dissipation at T
amb
=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 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 ± 0.1
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
3-digits marking for 0603 size
WFxxH 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
Approval sheet
Page 4 of 6 ASC_WFxxH_V02 Sep - 2011
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
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
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 D 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
D : ±0.5%
B : ±0.1%
Packaging code
T : 7” Reeled taping
Termination code
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.
Approval sheet
Page 5 of 6 ASC_WFxxH_V02 Sep - 2011
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. ±(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. ±(1%+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. ±(1%+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
Approval sheet
Page 6 of 6 ASC_WFxxH_V02 Sep - 2011
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±0.30 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
- Chip resistors 5,000 pcs/reel for WF12H, WF08H, WF06H.
- Chip resistors 10,000 pcs/reel for WF04H.
