Approval sheet
WF12W, WF08W, WF06W, WF04W
±
0.5%,
±
0.25%,
±
0.1%,
±
0.05%
TC10
High Precision Thin Film chip resistors
Size 1206, 0805, 0603, 0402
*Contents in this sheet are subject to change without prior notice.
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ASC_WFxxW_V06
Nov.2011
Approval sheet
FEATURE
1. SMD metal film resistor
2. High reliability and stability of 0.25% and below per customer request
3. High performance of TCR: 10 ppm/K and below per customer request
4. Low current noise
5. RoHS compliant and lead free
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. Construction of Chip-R WFxxW
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ASC_WFxxW_V06
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Approval sheet
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range
TCR (ppm/°C)
Max. dissipation at T
amb
=70°C
Max. Operation Voltage (DC or RMS)
Max. Overload Voltage (DC or RMS)
Operation temperature
Note :
1.
2.
This is the maximum voltage that may be continuously supplied to the resistor element, see “IEC publication
60115-8”
Max. Operation Voltage : So called RCWV (Rated Continuous Working Voltage) is determined by
1/8W
150V
300V
1/8W
100V
200V
25Ω ~ 300KΩ
( E24 +E192 )
WF12W
1206 ( 3216 )
General Specification
WF08W
0805 ( 2012 )
WF06W
0603 ( 1608 )
WF04W
0402 ( 1005 )
±0.5%, ±0.25%, ±0.1%, ±0.05%
*
25Ω ~ 200KΩ
( E24 +E192 )
25Ω ~ 100KΩ
( E24 +E192 )
25Ω ~ 20KΩ
( E24 +E192 )
±10
ppm/°C
1/10W
50V
100V
1/16W
25V
50V
- 55~ +155’C
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
3.
Tolerance
±0.05%
is upon requested
DIMENSIONS:(unit:mm)
Type
L
W
A
B
t
WF12W
3.05
±
0.15
1.55
±
0.15
0.40
±
0.20
0.40
±
0.20
0.55
±
0.15
WF08W
2.00
±
0.10
1.25
±
0.10
0.25
±
0.20
0.40
±
0.20
0.50
±
0.15
WF06W
1.55
±
0.10
0.80
±
0.10
0.25
±
0.15
0.30
±
0.15
0.45
±
0.15
WF04W
1.00
±
0.10
0.50
±
0.05
0.15
±
0.10
0.25
±
0.10
0.30
±
0.05
Protective coat
t
B
A
End termination
Resistive layer
Ceramic Substrate
W T
1001
L
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ASC_WFxxW_V06
Nov.2011
Approval sheet
MARKING
3-digits marking for 0603 size
WFxxW has same marking rule as WRxx ±1%.
4-digits marking for 1206, 0805 size
For E24+E96, 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
4-digits marking
100Ω
1000
6800Ω
6801
47000Ω
4702
No marking code for 0402 size
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E192 & E24 series for resistors with a tolerance of
±0.5%, ±0.25%, ±0.1%.
The values of the E24/E192 series are in accordance with “IEC publication 60063”.
Derating
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.
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Approval sheet
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 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
Size code
WF12: 1206
WF08: 0805
WF06: 0603
WF04: 0402
W
Type code
W: TCR 10ppm
xxxx
Resistance code
E192+E24:
R is first code followed by
3 significant digits.
100Ω =1000
37.4KΩ =3742
B
Tolerance
A :
±0.05%
B :
±0.10%
C :
±0.25%
D :
±0.50%
T
Packaging code
T : Reeled
L
Termination code
L = lead free
1. Reeled tape packaging: 8mm width paper taping.
5,000pcs/reel for WF12W, WF08W, WF06W;
10,000pcs/reel for WF04W.
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Nov.2011
