Walsin Technology Corporation
Page 1 of 9 WfxxU Ver.9 Sep.2008
WF12U, WF08U, WF06U, WF04U
±
±±
±0.5%, ±
±±
±0.1%
TC25
High Precision Thin Film chip resistors
Size 1206, 0805, 0603, 0402
Customer :
Approval No :
Issue Date :
Customer Approval :
Walsin Technology Corporation
Page 2 of 9 WfxxU Ver.9 Sep.2008
FEATURE
1. SMD metal film resistor
2. High reliability and stability of 0.1% and below per customer request
3. High performance of TCR: 25 ppm/K and below per customer request
4. Low current noise
APPLICATION
• Medical equipment
• Measuring instrument
• Communication device
• Computer
• Printer
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 layer that is applied to the top surface of the substrate. The
composition of the resistive layer 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
environmental soldering issue, the outer layer of these end terminations is a Lead-free solder .
Fig 1. Consctruction of Chip-R WFxxU
Walsin Technology Corporation
Page 3 of 9 WfxxU Ver.9 Sep.2008
QUICK REFERENCE DATA
Item General Specification
Series No. WF12U WF08U WF06U WF04U
Size code 1206 ( 3216 ) 0805 ( 2012 ) 0603 ( 1608 ) 0402 ( 1005 )
Resistance Tolerance ±0.5%, ±0.1%
Resistance Range 10Ω ~ 1MΩ
( E24 +E96 ) 10Ω ~ 1MΩ
( E24 +E96 ) 10Ω ~ 330KΩ
( E24 +E96 ) 10Ω ~ 100KΩ
( E24 +E96 )
TCR (ppm/°C) +25 ~ -25 ppm/°C
Max. dissipation at T
amb
=70°C 1/8W 1/10W 1/16W 1/16W
Max. Operation Voltage (DC or RMS) 150V 100V 50V 25V
Climatic category 55/125/56
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.
Dimensions:
Type
WF12U WF08U WF06U WF04U
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
A
0.45 ±
±±
± 0.20 0.25 ±
±±
± 0.20 0.25 ±
±±
± 0.15 0.20 ±
±±
± 0.10
B
0.45 ±
±±
± 0.20 0.40 ±
±±
± 0.20 0.30 ±
±±
± 0.15 0.25 ±
±±
± 0.10
t
0.60 ±
±±
± 0.15 0.50 ±
±±
± 0.15 0.45 ±
±±
± 0.15 0.35 ±
±±
± 0.05
Protective coat
Resistive layer
End termination
Ceramic Substrate
t
B
A
T
W
L
1001
Walsin Technology Corporation
Page 4 of 9 WfxxU Ver.9 Sep.2008
Marking
3-digits marking for 0603 size
WFxxU 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
±0.5%, ±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
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
Walsin Technology Corporation
Page 5 of 9 WfxxU Ver.9 Sep.2008
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 within lead-free solder bath. 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.
Catalogue numbers
The resistors have a catalogue number starting with .
WF06
U
xxx
D
T
Size code
WF12: 1206
WF08: 0805
WF06: 0603
WF04: 0402
Type code
U: TCR 25ppm
Resistance code
E96 +E24:
R is first code followed by
3 significant digits.
E24: 39R0=>390
820R =>821
E96: 17R8 =>25X
178R =>25A
Tolerance
D : ±0.5%
C: ±0.25%
B : ±0.1%
Packaging code
T : Reeled
1. Reeled tape packaging: 8mm width paper taping.
5,000pcs/reel for WF12U, WF08U, WF06U;
10,000pcs/reel for WF04U.
TEST AND REQUIREMENTS(JIS C 5201-1 : 1998)
Walsin Technology Corporation
Page 6 of 9 WfxxU Ver.9 Sep.2008
REQUIREMENT
TEST PROCEDURE Resistor
DC resistance
Clause 4.5 DC resistance values measured
<10Ω@0.1V, <100Ω@0.3V, <1KΩ@1.0V,
<10KΩ@3V, <100KΩ@10V,<1MΩ@25V, <10MΩ@30V
Within the specified tolerance ±0.5%, ±0.1%
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)
R
1
: Resistance at reference temperature
R
2
: Resistance at test temperature
t
1
: 20°C+5°C-1°C
Test temperature –55°C ~ +125°C
TCR: ≦±25 ppm/°C
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. ±(0.2%+0.05Ω)
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. ±(0.1%+0.05Ω)
Solderability
IEC 60068-2-58:2004
Un-mounted chips completely immersed for 3±0.3 second
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 +125°C±3°C, 2~3 minutes at
20°C+5°C-1°C, total 5 continuous cycles
no visible damage
∆R/R max. ±(0.1%+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. ±(0.5%+0.05Ω)
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. ±(0.5%+0.05Ω)
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. ±(0.1%+0.05Ω)
Adhision
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 1minute R≧10GΩ
Dielectric Withstand
Voltage
JISC5201-1:1998
Clause 4.7
Apply the maximum overload voltage (AC) for 1 minute No breakdown or flashover
Walsin Technology Corporation
Page 7 of 9 WfxxU Ver.9 Sep.2008
PACKAGING
Paper Tape specifications (unit :mm)
FP0
D
Series No. A B W D E
WF12 3.60±0.20 2.00±0.20 8.00±0.30 3.50±0.20 1.75±0.10
WF08 2.40±0.20 1.65±0.20 8.00±0.30 3.50±0.20 1.75±0.10
WF06 1.90±0.20 1.10±0.20 8.00±0.30 3.50±0.20 1.75±0.10
WF04 1.20±0.10 0.7±0.10 8.00±0.20 3.50±0.05 1.75±0.10
Series No. F P0 ΦD T
WF12 4.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
Max. 1.0
WF08 4.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
Max. 1.0
WF06 4.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
0.65±0.05
WF04 2.00±0.10 4.00±0.10
1.0 0.0
50.1
+
−
Φ
0.40±0.05
Reel dimensions
A
B
C
D
Symbol A B C D
(unit : mm) Φ178.0±2.0 Φ60.0±1.0 13.0±0.2 9.0±0.5
Walsin Technology Corporation
Page 8 of 9 WfxxU Ver.9 Sep.2008
Taping quantity
- Chip resistors 5,000 pcs per reel ( WF12U, WF08U, WF06U )
- Chip resistors 10,000 pcs per reel ( WF04U )
