Walsin Technology Corporation
WW25X
±1%, ±2%, ±5%
Low ohmic power chip resistors
Size 2512
Customer
:
Approval No :
Issue Date
:
Customer Approval :
Page 1 of 7
WW25X
Version 09
Nov.-2006
Walsin Technology Corporation
FEATURE
1. High power rating and compact size
2. High reliability and stability
3. Reduced size of final equipment
4. Lead free product is upon customer requested.
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 a Lead-tin alloy.
Fig 1. Consctruction of Chip-R
Page 2 of 7
WW25X
Version 09
Nov.-2006
Walsin Technology Corporation
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)
Climatic category (IEC 60068)
≤
2100 ppm/°C
≤
1000 ppm/°C
≤
500 ppm/°C
≤
400 ppm/°C
1W
250V
55/155/56
±5%
(E24)
0.02Ω ~ 0.91Ω
General Specification
WW25X
2512 ( 6432 )
±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.
Tolerance of TCR=±200ppm/°C
Mechanical Data
Symbol
L
W
T
Tt
Tb
Dimensions (mm)
6.40±0.20
3.20±0.20
0.60±0.10
0.65±0.25
0.90±0.25
Page 3 of 7
WW25X
Version 09
Nov.-2006
Walsin Technology Corporation
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
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of
±5%, ±2%
&
±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
Page 4 of 7
WW25X
Version 09
Nov.-2006
Walsin Technology Corporation
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
one minute. 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 60 seconds. Typical examples of soldering processes that provide reliable joints without
any damage are given in Fig 3.
Fig 3. Infrared soldering profile for Chip Resistors WW25X
Catalogue numbers
The resistors have a catalogue number starting with .
WW25
Size code
WW25
: 2512
X
Type code
X : Normal
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%
G :
±2%
F :
±1%
T
Packaging code
T : Reeled
_
Termination code
_ = SnPb base (“_” means
a blank)
L
=
Sn base (lead free)
Page 5 of 7
WW25X
Version 09
Nov.-2006
京公网安备 11010802033920号
EEWORLD
