Approval sheet
Page 1 of 9 ASC_WFxxP_V03 MAR - 2017
WF25P, WF20P, WF10P, WF12P, WF08P,
WF06P, WF04P
5%, 1%, 0.5%, 0.1% 1Ω ~ 10MΩ
Thick Film High Power Chip Resistors
Size 2512 2W, 2010 1W, 1210 1/2W,
1206 1/2W, 0805 1/4W, 0603 1/8W, 0402 1/8W
*Contents in this sheet are subject to change without prior notice.
Approval sheet
Page 2 of 9 ASC_WFxxP_V03 MAR - 2017
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
5. Flame Retardant
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 Tin (lead free) alloy.
Fig 1. Construction of Chip-R
Approval sheet
Page 3 of 9 ASC_WFxxP_V03 MAR - 2017
QUICK REFERENCE DATA
Item
General Specification
Series No.
WF25P
WF20P
WF10P
WF08P
WF06P
WF04P
Size code
2512
(6432)
2010
(5025)
1210
(3225)
0805
(2012)
0603
(1608)
0402
(1005)
Resistance
Tolerance
1%, 0.5%, 0.1% ( E24+E96),
5% (E24)
Resistance
Range
0Ω,1 ~ 1M
0Ω,1 ~ 10M
0Ω,1 ~ 1M
TCR (ppm/C)
10 ~ 1M
< 10
±100
±100
±100
±100
±100
±100
±100
±150
±100
±150
±100
-200/+400
Max.
dissipation at
Tamb=70C
2 W
1 W
1/2 W
1/4 W
1/8 W
1/8 W
Max.
Operation
Voltage
300V
200V
200V
150V
50V
50V
Max. Overload
Voltage
500V
400V
400V
300V
100V
100V
Operation
Temperature
- 55/+155’C
Note :
1. This is the maximum voltage that may be continuously supplied to the resistor element, see “IEC publication
60115-8”
2. Max. Operation Voltage : So called RCWV (Rated Continuous Working Voltage) is determined by
ValueResistancePower RatedRCWV
or Max. RCWV listed above, whichever is lower.
3. 2W loading with total solder-pad and trace size of 300 mm2
TEST CONDITION FOR JUMPER (0 )
Item
WF25P
WF20P
WF10P
WF08P
WF04P
Power Rating
2W
1W
1/2W
1/4W
1/8W
Resistance
Max. 20m
Max. 20m
Max. 20m
Max. 20m
Max. 50m
Rated Current
10A
7A
5A
4A
1.5A
Peak Current
25A
17.5A
12.5A
10A
3.8A
Operating
Temperature
-55 ~ +155C
Approval sheet
Page 4 of 9 ASC_WFxxP_V03 MAR - 2017
MECHANICAL DATA
Unit: mm
Symbol
WF25P
WF20P
WF12P
WF10P
WF08P
WF06P
WF04P
L
6.30 0.20
5.00 0.20
3.10 0.15
3.10 0.15
2.00 0.10
1.60 0.10
1.00 0.05
W
3.10 0.20
2.50 0.20
1.60 0.15
2.50 0.15
1.25 0.10
0.80 0.10
0.50 0.05
T
0.60 0.15
0.60 0.10
0.55 0.10
0.55 0.10
0.50 0.15
0.45 0.15
0.35 0.05
Tt
0.60 0.25
0.60 0.25
0.50 0.25
0.50 0.25
0.40 0.20
0.30 0.10
0.20 0.10
Tb
1.80 0.25
0.60 0.25
0.50 0.25
0.50 0.25
0.40 0.20
0.30 0.15
0.25 0.10
102
Approval sheet
Page 5 of 9 ASC_WFxxP_V03 MAR - 2017
Recommended Solder Pad Dimensions
D
W
L
MARKING
For 0603 above size, each resistor is marked with a four-digit for 1% tolerance and three-digit for 5%
tolerance on the protective coating to designate the nominal resistance value.
For 0603, each resistor is marked with a three-digit!
For 0402, no marking !
For Jumper, 2512/2010 defines 0000, 1206/0805/0603 defines 000.
Example:
102 = 1k 16R0 = 16
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
Type
W
D
L
WF25P
3.7mm
2.45mm
7.6mm
102
16R0
Approval sheet
Page 6 of 9 ASC_WFxxP_V03 MAR - 2017
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 260C 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 235C during 2 seconds. The test
condition for no leaching is 260C 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 for Chip Resistors
CATALOGUE NUMBERS
The resistors have a catalogue number starting with .
WF25
P
102
J
T
L
Size code
WF25 : 2512
WF20 : 2010
WF12 : 1206
WF10 : 1210
WF08 : 0805
WF06 : 0603
WF04 : 0402
Type code
P :Power
2512 size = 2W
2010 size = 1W
1206 size = 1/2W
1210 size = 1/2W
0805 size = 1/4W
0603 szie = 1/8W
0402 size = 1/8W
Resistance code
5% E24: 2 significant digits
followed by No. of zeros
e.g.:
3ohm =3R0
10ohm =100
56Kohm =563
1% E24+E96:3 significant
digits
followed by No. of zeros
100 =1000
37.4K =3742
Tolerance
J : 5%
F : 1%
D : 0.5%
B : 0.1%
P : Jumper
Packaging
code
T : 7” Reel
taping
E : 7” Reel up
side down
taping
Termination
code
L = Sn base
(lead free)
Tape packaging WF12, WF10, WF08, WF06 : 8mm width paper taping 5,000pcs per reel.
WF04: 8mm width paper taping 10,000pcs per reel.
WF25, WF20: 12mm width plastic taping 4,000pcs per reel.
Approval sheet
Page 7 of 9 ASC_WFxxP_V03 MAR - 2017
TEST AND REQUIREMENTS
Basic specification : JIS C 5201-1 : 1998
TEST
PROCEDURE
REQUIREMENT
Clause 4.8
Temperature Coefficient
of Resistance (TCR )
Natural resistance change per change in degree
centigrade.
6
121
12 10
ttR RR
(ppm/C)
R1 : Resistance at reference temperature
R2 : Resistance at test temperature
t1 : 20°C+5°C-1°C
Refer to quick reference data for T.C.R
specification
Clause 4.13
Short time overload
5.0× Rated power or Max. Overload Voltage for 5 sec.
Measure resistance after 30 minutes..
R/R max. J:≦ ±(2%+0.1)
B,D, F:≦ ±(1%+0.05)
Clause 4.18
Resistance to soldering
heat
Un-mounted chips completely immersed for 10±1second
in a SAC solder bath at 260℃±5ºC
No visible damage
R/R max. J:≦ ±(1%+0.1)
B,D, F:≦ ±(0.5%+0.05)
Clause 4.17
Solderability
Un-mounted chips completely immersed for 2±0.5
second in a SAC solder bath at 235℃±5℃
Good tinning (>95% covered)
No visible damage
Clause 4.18
Leach Test
Un-mounted chips completely immersed for 60±1second
in a solder bath at 260℃±5℃
Ditto
Clause 4.19
Temperature cycling
30 minutes at -55°C±3°C, 2~3 minutes at 20°C+5°C-1°C,
30 minutes at +155°C±3°C, 2~3 minutes at
20°C+5°C-1°C, total 5 continuous cycles
No visible damage
R/R max. J≦ ±(1%+0.1)
B,D,F≦ ±(0.5%+0.05)
Clause 4.25
Load life (endurance)
1000 +48/-0 hours, loaded with RCWV or Vmax in
chamber controller 70±2ºC, 1.5 hours on and 0.5 hours
off
No visible damage
R/R max. J≦ (3%+0.1)
B,D,F≦ (1%+0.05)
Clause 4.24
Load life in Humidity
1000 +48/-0 hours, loaded with RCWV or Vmax in
humidity chamber controller at 40C2C and 90~95%
relative humidity, 1.5hours on and 0.5 hours off
No visible damage
R/R max. J≦ (3%+0.1)
B,D,F≦ (1%+0.05)
Clause 4.33
Bending strength
Resistors mounted on a 90mm glass epoxy resin
PCB(FR4); bending : 2 mm(2512;2010) 3mm(1206),
once for 10 seconds
No visible damage
R/R max. J≦ ±(1%+0.1)
B,D,F≦ ±(0.5%+0.05)
Clause 4.32
Adhesion
Pressurizing force: 5N, Test time: 10±1sec
No remarkable damage or removal of the
terminations
Insulation Resistance
Clause 4.6
Apply the maximum overload voltage (DC) for 1minute
R≧10GΩ
Dielectric Withstand
Voltage
Clause 4.7
Apply the maximum overload voltage (AC) for 1 minute
No breakdown or flashover
Approval sheet
Page 8 of 9 ASC_WFxxP_V03 MAR - 2017
PACKAGING
Paper Tape(WF12P, WF10P, WF08P, WF06P, WF04P) & Plastic Tape(WF25P;WF20P)
(unit :mm)
Series No.
A
B
W
F
E
WF25P
6.90±0.20
3.60±0.20
12.00±0.30
5.50±0.10
1.75±0.10
WF20P
5.50±0.20
2.80±0.20
WF12P
3.60±0.20
2.00±0.20
8.00±0.30
3.50±0.20
1.75±0.10
WF10P
3.60±0.20
3.00±0.20
8.00±0.30
3.50±0.20
1.75±0.10
WF08P
2.40±0.20
1.65±0.20
8.00±0.30
3.50±0.20
1.75±0.10
WF06P
1.90±0.20
1.10±0.20
8.00±0.30
3.50±0.20
1.75±0.10
WF04P
1.20±0.10
0.70±0.10
8.00±0.30
3.50±0.20
1.75±0.10
Series No.
P1
P0
D
T
WF25P
4.00±0.10
4.00±0.10
1.0 0.0
50.1
Max. 1.2
WF20P
WF12P
Max. 1.0
WF10P
4.00±0.10
4.00±0.10
1.0 0.0
50.1
Max. 1.0
WF08P
4.00±0.10
4.00±0.10
1.0 0.0
50.1
Max. 1.0
WF06P
4.00±0.10
4.00±0.10
1.0 0.0
50.1
0.65±0.05
WF04P
2.00±0.10
4.00±0.10
1.0 0.0
50.1
0.40±0.05
Reel dimensions
Approval sheet
Page 9 of 9 ASC_WFxxP_V03 MAR - 2017
(unit : mm)
Reel / Tape
A
B
C
D
7” reel for 12mm tape
178.0±2.0
60.0±1.0
13.0±0.2
12.4±1.0
7” reel for 8mm tape
9.0±0.5