WW20X
±
1%,
±
5%
Low ohmic power chip resistors
Size 2010
Customer
:
Approval No :
Issue Date
:
Customer Approval :
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WW20X
Version 14
April.-2010
FEATURE
1. High power rating and compact size
2. High reliability and stability
3. Reduced size of final equipment
4. LoHS 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. Consctruction of Chip-R
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WW20X
Version 14
April.-2010
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range
TCR (ppm/°C)
0.02Ω
≤
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)
≤
2100 ppm/°C
≤
1000 ppm/°C
≤
500 ppm/°C
≤
400 ppm/°C
0.5 W
200V
400V
55/155/56
≤
1500 ppm/°C
≤
1000 ppm/°C
≤
500 ppm/°C
≤
300 ppm/°C
±5%
(E24)
0.02Ω ~ 0.91Ω
General Specification
WW20X
2010(5025)
±1%
(E96)
0.02Ω ~ 0.976Ω
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.
4.
Tolerance of TCR=±200ppm/°C
Resistance value will be changed by soldering condition and design of soldering pad,please design products in
consideration of this change of resistance value.
MECHANICAL DATA
Symbol
L
W
T
Tt
Tb
Dimensions (mm)
5.00±0.20
2.50±0.20
0.55±0.10
0.65±0.25
0.60±0.25
MARKING
Each resistor is marked with a four-digit code on the protective coating to designate the nominal resistance
value.
Example:
R010 = 0.01Ω
R510 = 0.51Ω
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WW20X
Version 14
April.-2010
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
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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WW20X
Version 14
April.-2010
CATALOGUE NUMBERS
The resistors have a catalogue number starting with .
WW20
Size code
WW20 : 2010
X
Type code
X : Normal type
R020
Resistance code
E96 + E24:
R is first digit followed by 3
significant digits.
0.020Ω = R020
0.510Ω = R510
0.025Ω = R025
J
Tolerance
J :
±5%
F :
±1%
T
Packaging code
T : 7” Reel taping
L
Termination code
L
=
Sn base (lead
free)
TEST AND REQUIREMENTS(JIS C 5201-1 : 1998)
Essentially all tests are carried out according to the schedule of IEC publication 115-8, category
LCT/UCT/56(rated
temperature range :
Lower Category Temperature, Upper Category Temperature;
damp
heat, long term, 56 days). The testing also meets the requirements specified by EIA, EIAJ and JIS.
The tests are carried out in accordance with IEC publication 68, "Recommended basic climatic and mechanical
robustness testing procedure for electronic components" and under standard atmospheric conditions according
to IEC 60068-1, subclause 5.3. Unless otherwise specified, the following value supplied :
Temperature: 15°C to 35°C.
Relative humidity: 45% to 75%.
Air pressure: 86kPa to 106 kPa (860 mbar to 1060 mbar).
All soldering tests are performed with midly activated flux.
TEST
Temperature Coefficient
of Resistance(T.C.R)
Clause 4.8
PROCEDURE
Natural resistance change per change in degree centigrade.
REQUIREMENT
Refer to
“QUICK REFERENCE DATA”
(ppm/°C) t
1
: 20°
C+5°
C-1°
C
R
2
−
R
1
×
10
6
R
1
(
t
2
−
t
1
)
R
1
: Resistance at reference temperature
R
2
: Resistance at test temperature
Short time overload
(S.T.O.L)
Clause 4.13
Resistance to soldering
heat(R.S.H)
Clause 4.18
Solderability
Clause 4.17
Temperature cycling
Clause 4.19
Load life (endurance)
Clause 4.25
Load life in Humidity
Clause 4.24
Un-mounted chips completely immersed for2±0.5second in a SAC solder bath good tinning (>95% covered)
at 235℃±5℃
no visible damage
30 minutes at -55°C±3°C, 2~3 minutes at 20°
C+5°
C-1° 30 minutes at
C,
+155°C±3°C, 2~3 minutes at 20°
C+5°
C-1° total 5 continuous cycles
C,
no visible damage
∆R/R
max.
±(1%+0.005Ω)
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
∆R/R
max.
±(2%+0.005Ω)
is less.
Un-mounted chips completely immersed for 10±1second in a SAC solder bath no visible damage
at 260℃±5ºC
∆
R/R max.
±(1%+0.005Ω)
1000 +48/-0 hours, loaded with RCWV or Vmax in chamber controller 70±2ºC,
∆R/R
max.
±(3%+0.005Ω)
1.5 hours on and 0.5 hours off
1000 +48/-0 hours, loaded with RCWV or Vmax in humidity chamber controller
∆R/R
max.
±(3%+0.005Ω)
at 40°
C±2° and 90~95% relative humidity, 1.5hours on and 0.5 hours off
C
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WW20X
Version 14
April.-2010
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