Approval sheet
WW25W, WW20W, WW10W, WW12W,
WW08W, WW06W
±
1%,
±
5%
Thick Film Normal Low Ohm Chip Resistors
RoHS Exemption free and Lead free
Size 2512, 2010, 1210, 1206, 0805, 0603
*Contents in this sheet are subject to change without prior notice.
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ASC_WWxxW_V01
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Approval sheet
FEATURE
1. High power rating and low TCR
2. High reliability and stability
3. Reduced size of final equipment
4. RoHS exemption free 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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Approval sheet
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance
Tolerance
Resistance
Range
TCR (ppm/°C)
10 - 20mΩ:
±1000
22 - 39mΩ:
±600
40 - 47mΩ:
±200
50 - 91mΩ:
±100
100 - 910mΩ:
±100
10 - 20mΩ:
±1000
22 - 39mΩ:
±600
40 - 47mΩ:
±200
50 - 91mΩ:
±100
100 - 910mΩ:
±100
10 - 20mΩ:
±600
22 - 39mΩ:
±400
40 - 47mΩ:
±200
50 - 91mΩ:
±100
100 - 910mΩ:
±100
10 - 20mΩ:
±1000
22 - 39mΩ:
±600
40 - 47mΩ:
±200
50 - 91mΩ:
±100
100 - 910mΩ:
±100
10 - 20mΩ:
±1000
22 - 39mΩ:
±600
40 - 47mΩ:
±400
50 - 91mΩ:
±200
100 - 910mΩ:
±100
50 - 91mΩ:
±400
100 - 910mΩ:
±200
General Specification
WW25W
2512 (6432)
WW20W
2010 (5025)
WW10W
1210 ( 3225 )
WW12W
1206 ( 3216 )
WW08W
0805 ( 2012 )
WW06W
0603 ( 1608 )
±5%, ±1%
0.010Ω ~ 0.910Ω,
E24
0.050Ω ~ 0.910Ω,
E24
Max. dissipation
at T
amb
=70°C
Operation
temperature
1W
3/4W
2/3 W
1/3 W
1/4 W
1/8 W
-55 ~ +155’C
MECHANICAL DATA
Symbol
L
W
T
Tt
Tb
WW25W
6.30
±
0.20
3.10
±
0.20
0.60
±
0.15
0.60
±
0.25
0.90
±
0.25
WW20W
5.00
±
0.20
2.50
±
0.20
0.60
±
0.10
0.60
±
0.25
0.60
±
0.25
WW10W
3.10
±
0.10
2.60
±
0.10
0.55
±
0.10
0.50
±
0.25
0.50
±
0.25
WW12W
3.10
±
0.10
1.60
±
0.10
0.55
±
0.10
0.50
±
0.25
0.50
±
0.25
WW08W
2.00
±
0.10
1.25
±
0.10
0.50
±
0.10
0.40
±
0.20
0.40
±
0.20
WW06W
1.60
±
0.10
0.80
±
0.10
0.45
±
0.10
0.30
±
0.20
0.30
±
0.20
RECOMMENDED SOLDERING PAD
Symbol
WL
D
L
WW25W
3.70mm
1.60mm
7.60mm
WW20W
3.00mm
1.50mm
6.80mm
WW10W
3.00mm
1.30mm
4.70mm
WW12W
1.80mm
1.30mm
4.70mm
WW08W
1.30mm
1.15mm
3.50mm
WW06W
0.90mm
1.00mm
3.00mm
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Approval sheet
MARKING
4-digits marking for 2512, 2010, 1210, 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.
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Approval sheet
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E24 series for resistors with a tolerance of
±5%
&
±1%.
The values of the E24 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_WWxxW_V01
FEB - 2016
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