WK12K, WK08K, WK06K, WK04K, WK02K
±
1.0%,
±
0.5%
Thick Film TC50/TC100
High Precision Thick Film chip resistors
Size 1206, 0805, 0603, 0402, 0201
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FEATURE
1. SMD Thick film resistor
2. High reliability and stability
3. High performance of TCR: 50 ppm/K
4. High precision
5. RoHS compliant & 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 .
73
Fig 1. Construction of Chip-R WKxxK
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QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range/
TCR (ppm/°C)
3.3 ~ 9.76Ω:
50ppm
10Ω ~ 4.7MΩ:
50ppm-
3.3 ~ 9.76Ω:
50ppm
10Ω ~ 3.3MΩ:
50ppm
General Specification
WK12K
1206 ( 3216 )
WK08K
0805 ( 2012 )
WK06K
0603 ( 1608 )
WK04K
0402 ( 1005 )
WK02K
0201 ( 0603 )
±1.0%, ±0.5%
( E24 +E96 )
3.3 ~ 9.76Ω: 100ppm
10 ~ 97.6Ω: 100ppm
100Ω ~ 1MΩ: 50ppm
1.02~3.3MΩ: 100ppm
10 ~ 97.6Ω:
100ppm
100Ω ~ 1MΩ:
50ppm
1.02~3.3MΩ:
100ppm
51 ~ 976Ω:
100ppm
1KΩ ~ 1MΩ:
50ppm
Max. dissipation at
T
amb
=70°C
Max. Operation
Voltage (DC or RMS)
Max. Overload Voltage
(DC or RMS)
Climatic category
1/4W
200V
400V
1/8W
150V
300V
1/10W
50V
100V
55/125/56
1/16W
50V
100V
1/20W
25V
50V
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
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
3.
Green color overcoat.
DIMENSION (unit : mm)
Type
L
W
t
A
B
WK12K
3.20
±
0.15
1.60
±
0.15
0.60
±
0.10
0.50
±
0.25
0.50
±
0.25
WK08K
2.00
±
0.10
1.25
±
0.10
0.60
±
0.10
0.40
±
0.20
0.40
±
0.20
WK06K
1.60
±
0.10
0.80 +0.15/-0.05
0.45
±
0.10
0.25
±
0.10
0.30
±
0.10
WK04K
1.00
±
0.05
0.50
±
0.05
0.35
±
0.05
0.20
±
0.10
0.25 +0.05/-0.10
WK02K
0.60
±
0.03
0.30
±
0.03
0.23
±
0.03
0.10
±
0.05
0.15
±
0.05
Protective coat
t
B
A
End termination
Resistive layer
Ceramic Substrate
W T
101
1001
L
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MARKING
Each resistor is marked with 3 digits for E24 and 4 digits for E96 on the protective coating to designate the
nominal resistance value of E24 and E96.
0603 size has only marking with 3 digits for E24 and no marking for E96 !
0402/ 0201 size has no marking !
Example
RESISTANCE
MARKING
100Ω
101
562KΩ
5623
51.1Ω
51R1
No marking code for 0402/ 0201 size
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E24 & E96 series for resistors with a tolerance of
±1.0%, ±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, 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 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 .
WK12
Size code
WK12: 1206
WK08: 0805
WK06: 0603
WK04: 0402
WK02: 0201
K
Type code
TCR
50ppm/100ppm
4990
Resistance code
E24 +E96:
First 3 significant digits
represent resistance code
and followed by number of
zero.
E24: 39R0=>39R0
820R =>8200
E96: 49R9 =>49R9
499R =>4990
D
Tolerance
F :
±1.0%
D :
±0.5%
T
Packaging code
T : 7” Reeled
A : 7” Reeled
15kpcs
L
Termination
code
L : lead free
1. Reeled tape packaging: 8mm width paper taping.
5,000pcs/reel for WK12, WK08, WK06;
10,000pcs/reel for WK04,
15,000pcs/reel for WK02
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