Approval sheet
WW12X, WW08X, WW06X, WW04X
±
1%,
±
5%
Thick Film Low ohm chip resistors
Size 1206, 0805, 0603, 0402
*Contents in this sheet are subject to change without prior notice.
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ASC_WWxxX_V12
Nov.- 2011
Approval sheet
FEATURE
1. High power rating and compact size
2. High reliability and stability
3. Reduced size of final equipment
4. RoHS compliant and Lead free products
APPLICATION
•
•
•
•
•
•
•
Power supply
PDA
Digital meter
Computer
Automotives
Battery charger
DC-DC power converter
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 Tin (lead free) alloy.
Fig 1. Construction of Chip-R
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ASC_WWxxX_V12
Nov.- 2011
Approval sheet
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range
TCR (ppm/°C)
0.01Ω
≤
Rn < 0.05Ω
0.05Ω
≤
Rn < 0.10Ω
0.10Ω
≤
Rn < 0.50Ω
0.50Ω
≤
Rn < 1Ω
Max. dissipation at T
amb
=70°C
Max. Operation Voltage (DC or RMS)
Max. Overload voltage (DC or RMS)
Climatic category (IEC 60068)
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
0.010Ω ~
0.976Ω
≤
2100 ppm/°C
≤
1000 ppm/°C
≤
500 ppm/°C
≤
400 ppm/°C
1/4 W
200V
400V
0.020Ω ~
0.976Ω
≤
1500 ppm/°C
≤
1000 ppm/°C
≤
500 ppm/°C
≤
300 ppm/°C
1/8 W
100V
200V
55/155/56
≤
500 ppm/°C
≤
300 ppm/°C
1/10 W
50V
100V
WW12X
1206 ( 3216 )
General Specification
WW08X
0805 ( 2012 )
WW06X
0603 ( 1608 )
±5%, ±1%
0.10Ω ~ 0.976Ω
N/a
N/a
≤
600 ppm/°C
≤
600 ppm/°C
1/16 W
WW04X
0402(1005)
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
MECHANICAL DATA
Symbol
L
W
T
Tt
Tb
WW12X
3.10
±
0.10
1.60
±
0.10
0.60
±
0.15
0.50
±
0.20
0.45
±
0.20
WW08X
2.00
±
0.10
1.25
±
0.10
0.50
±
0.15
0.40
±
0.20
0.40
±
0.20
WW06X
1.60
±
0.10
0.80
±
0.10
0.45
±
0.15
0.30
±
0.10
0.30
±
0.20
WW04X
1.00
±
0.05
0.50
±
0.05
0.35
±
0.05
0.20
±
0.10
0.25
±
0.10
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ASC_WWxxX_V12
Nov.- 2011
Approval sheet
MARKING
4-digits marking for 1206, 0805 size
Each resistor is marked with a four-digit code on the protective coating to designate the nominal resistance
value.
3-digits marking for 0603 size
Each resistor is marked with a
three
-digit code on the protective coating to designate the nominal resistance
value.
WW04X series has no marking on the product overcoat for both 5% & 1%.
Marking code list.
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ASC_WWxxX_V12
Nov.- 2011
Approval sheet
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of
±5%
&
±1%.
The values of the E24/E96 series are in accordance with “IEC publication 60063”.
Derating curve
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
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
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ASC_WWxxX_V12
Nov.- 2011
PCB Design
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