Approval sheet
WF12H, WF08H, WF06H, WF04H
±
0.5%,
±
0.1%
Thick film high precision chip resistors
Size 1206, 0805, 0603, 0402
*Contents in this sheet are subject to change without prior notice.
Page 1 of 6
ASC_WFxxH_V02
Sep - 2011
Approval sheet
FEATURE
1. Small size and light weight
2. High reliability and stability
3. Reduced size of final equipment
4. High precision
5. Higher component and equipment reliability
6. RoHS compliant & Lead free products.
APPLICATION
•
•
•
•
•
Power supply
PDA
Digital meter
Computer
Palmtop computers
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
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ASC_WFxxH_V02
Sep - 2011
Approval sheet
QUICK REFERENCE DATA
Item
Series No.
Size code
Resistance Range
Resistance Tolerance
TCR (ppm/°C) 10Ω≤ R
≤
1MΩ
Max. dissipation at T
amb
=70°C
Max. Operation Voltage (DC or RMS)
Max. overload voltage (DC or RMS)
Climatic category
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
1/4 W
200V
400V
150V
300V
55/155/56
WF12H
1206 (3216)
General Specification
WF08H
0805 (2125)
WF06H
0603 (1608)
WF04H
0402 (1005)
10Ω ~ 1MΩ ( E96+E24 series)
±0.5%, ±0.1%
≤ ±
100 ppm/°C
1/8 W
1/10 W
50V
100V
1/16W
50V
100V
RCWV
=
Rated Power
×
Resistance Value
or Max. RCWV listed above, whichever is lower.
3.
Non E96 series resistance upon requested.
DIMENSIONS(unit : mm)
Part No
L
W
Tt
Tb
T
WF12H
3.10
±
0.1
1.60
±
0.1
0.50
±
0.2
0.45
±
0.2
0.65
±
0.15
WF08H
2.0
±
0.10
1.25
±
0.10
0.40
±
0.20
0.40
±
0.20
0.5
±
0.15
WF06H
1.60
±
0.10
0.80
±
0.10
0.30
±
0.10
0.30
±
0.20
0.45
±
0.15
WF04H
1.00±0.05
0.50±0.05
0.20±0.10
0.25±0.10
0.35±0.05
MARKING
3-digits marking for 0603 size
WFxxH has same marking rule as WRxx ±1%.
4-digits marking for 1206, 0805 size
Each resistor is marked with a four digits code on the protective coating to designate the nominal resistance
value. For values below 97Ω6 the R is used as a digit. For values of 100Ω or greater, the first 3 digits are
significant, the fourth digit indicates the number of multiple to follow.
Example
RESISTANCE
4-digits marking
10Ω
10R0
12Ω
12R0
100Ω
1000
6800Ω
6801
47000Ω
4702
No marking code for 0402 size
Page 3 of 6
ASC_WFxxH_V02
Sep - 2011
Approval sheet
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E96 & E24 series for resistors with a tolerance of
±0.5%, ±0.1%.
The values of the E24/E96 series are in accordance with “IEC publication 60063”.
Derating
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
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 for Chip Resistors
CATALOGUE NUMBERS
The resistors have a catalogue number starting with :
WF06
Size code
WF12
WF08
WF06
WF04
: 1206
: 0805
: 0603
: 0402
Type code
H : High precision,
<1%, TCR>50ppm
H
3742
Resistance code
E96+E24:
3 significant digits followed
by no. of zeros
102Ω
37.4KΩ
220Ω
=1020
=3742
=2200
D
Tolerance
D :
±0.5%
B :
±0.1%
T
Packaging code
T
: 7” Reeled taping
L
Termination code
L
=
Sn base (lead
free)
Reeled tape packaging
0402.
: 8mm width paper taping 5000pcs per 7” reel for 1206/0805/0603, 10000pcs per 7” reel for
Page 4 of 6
ASC_WFxxH_V02
Sep - 2011
Approval sheet
TEST AND REQUIREMENTS(JIS C 5201-1 : 1998)
TEST
DC resistance
Clause 4.5
PROCEDURE
DC resistance values measured at the test voltages specified below :
<10Ω@0.1V,
<100Ω@0.3V, <1KΩ@1.0V, <10KΩ@3V,
<10MΩ@30V
Refer to
“QUICK REFERENCE DATA”
(ppm/°C)
; t1 :
20°
C+5°
C-1°
C
REQUIREMENT
Within the specified tolerance
<100KΩ@10V, <1MΩ@25V,
Temperature
Coefficient of
Resistance(T.C.R)
Clause 4.8
Natural resistance change per change in degree centigrade.
R
2
−
R
1
×
10
6
R
1
(
t
2
−
t
1
)
R1 : Resistance at reference temperature
R2 : 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
Bending strength
Clause 4.33
Adhesion
Clause 4.32
Insulation Resistance
Clause 4.6
Dielectric Withstand
Voltage
Clause 4.7
Permanent resistance change after a 5second application of a voltage
∆R/R
max.
±(0.25%+0.05Ω)
2.5 times RCWV or the maximum overload voltage specified in the
above list, whichever is less.
Un-mounted chips completely immersed for 10±1second in a SAC no visible damage
solder bath at 260℃±5ºC
∆
R/R max.
±(0.25%+0.05Ω)
Un-mounted chips completely immersed for 2±0.5 second in a SAC good tinning (>95% covered)
solder bath at 235℃±5℃
no visible damage
30 minutes at -55°C±3°C, 2~3 minutes at 20°
C+5°
C-1° 30 minutes
C,
at +155°C±3°C, 2~3 minutes at 20°
C+5°
C-1° total 5 continuous
C,
cycles
no visible damage
∆R/R
max.
±(0.25%+0.05Ω)
1000 +48/-0 hours, loaded with RCWV or Vmax in chamber controller
∆R/R
max.
±(1%+0.1Ω)
70±2ºC, 1.5 hours on and 0.5 hours off
1000 +48/-0 hours, loaded with RCWV or Vmax in humidity chamber
∆R/R
max.
±(1%+0.1Ω)
controller at 40°C±2°C and 90~95% relative humidity, 1.5hours on
and 0.5 hours off
Resistors mounted on a 90mm glass epoxy resin PCB(FR4);
∆R/R
max.
±(0.25%+0.05Ω)
bending : 3 mm, once for 10 seconds
Pressurizing force: 5N, Test time: 10±1sec.
No remarkable damage or
removal of the terminations.
R≧10GΩ
No breakdown or flashover
Apply the maximum overload voltage (DC) for 1minute
Apply the maximum overload voltage (AC) for 1 minute
Page 5 of 6
ASC_WFxxH_V02
Sep - 2011
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