WF25V, WF20V, WF12V, WF08V
±
1%,
±
5%
High voltage chip resistors
Size 2512,2010,1206, 0805
Page 1 of 8
WFxxV_V08
Jul. 2010
00-S-R24-F
FEATURE
1. Special material and design for high working voltage require.
2.
Compatible with flow and reflow soldering
3.
Suitable for lead free soldering.
APPLICATION
•
•
•
•
Power supply
Automotive industry
Measurement instrument
Back light inverter
Medical or Military equipment
•
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 Tin (lead free) alloy.
Fig 1. Consctruction of Chip-R
Page 2 of 8
WFxxV_V08
Jul. 2010
00-S-R24-F
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Tolerance
Resistance Range
TCR (ppm/°C)
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
1W
2000V
4000V
1/2 W
1500V
3000V
55/155/56
WF25V
2512(6432 )
General Specification
WF 20V
2010 ( 5025 )
WF12V
1206 ( 3216 )
WF08V
0805 ( 2012 )
±1%,±5%
100 KΩ ~10 MΩ
±200ppm/°C
1/4 W
800V
1600V
1/8 W
400V
800V
68 KΩ ~10 MΩ
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
MECHANICAL DATA(unit : mm)
Symbol
L
W
T
Tt
Tb
WF25V
6.30
±
0.20
3.10
±
0.20
0.60
±
0.15
0.60
±
0.25
0.90
±
0.25
WF 20V
5.00
±
0.20
2.50
±
0.20
0.60
±
0.10
0.60
±
0.25
0.60
±
0.25
WF12V
3.10
±
0.15
1.60
±
0.15
0.55
±
0.10
0.50
±
0.25
0.50
±
0.25
WF08V
2.00
±
0.10
1.25
±
0.10
0.50
±
0.15
0.40
±
0.20
0.40
±
0.20
105
Page 3 of 8
WFxxV_V08
Jul. 2010
00-S-R24-F
MARKING
For E24 series, Each resistor is marked with a three–digit code on the protective coating to designate the
nominal resistance value. For E96 series, Each resistor is marked with a four–digit code on the protective
coating to designate the nominal resistance value.
Example:
105 = 1MΩ
105
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E24/E96 series for resistors with a tolerance of
±1%, ±5%.
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
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.
Page 4 of 8
WFxxV_V08
Jul. 2010
00-S-R24-F
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
CATALOGUE NUMBERS
The resistors have a catalogue number starting with .
WF25
Size code
WF25
WF20
WF12
WF08
: 2512
: 2010
: 1206
: 0805
V
Type code
V :High Voltage
105
Resistance code
5%, E24: 2 significant digits
followed by no. of zeros
100Ω
10KΩ
= 101_
= 103
J
Tolerance
J :
±5%
F :
±1%
T
Packaging code
T : 7” inch reel
1206:paper tape, 5kpcs/reel
2010,2512 :plastic tape,
4kpcs/reel
L
Termination code
L
=
Sn base (lead
free)
1%, E24+E96: 3 significant
digits followed by no. of
zeros
100Ω
37.4KΩ
=1000
=3742
Tape packaging WF12, WF08 : 8mm width paper taping 5,000pcs per reel.
WF25；WF20: 12mm width plastic taping 4,000pcs per reel.
Marking code : For E24 series , 3 digit marking code for J tol.. E96 series, 4 digit marking code for F tol.
Page 5 of 8
WFxxV_V08
Jul. 2010
00-S-R24-F
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