Approval sheet
Page 1 of 9 ASC_WR_V21 Mar.- 2012
WR12, WR08, WR06, WR04
±
±±
±1%, ±
±±
±5%
Thick Film General Purpose Chip Resistors
Size 1206, 0805, 0603, 0402
*Contents in this sheet are subject to change without prior notice.
Approval sheet
Page 2 of 9 ASC_WR_V21 Mar.- 2012
FEATURE
1. High reliability and stability
2. Reduced size of final equipment
3. Lower assembly costs
4. Higher component and equipment reliability
5.
RoHS compliant and Lead free products
APPLICATION
• Consumer electrical equipment
• EDP, Computer application
• Telecom application
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
within tolerance by laser cutting 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_WR_V21 Mar.- 2012
QUICK REFERENCE DATA
Item General Specification
Series No. WR12 WR08 WR06 WR04
Size code 1206(3216) 0805(2012) 0603(1608) 0402(1005)
Resistance Range 1Ω~10MΩ (±5% tolerance), Jumper
1Ω~10MΩ (±1% tolerance),
Resistance Tolerance
±1%
E96/E24
±5%
E24
±1%
E96/E24
±5%
E24
±1%
E96/E24
±5%
E24
±1%
E96/E24
±5%
E24
TCR (ppm/°C)
10MΩ ≥R＞10Ω
R≤10Ω
≤ ± 100
-200~+400
Max. dissipation
@ T
amb
=70°C 1/4 W 1/8 W 1/10 W 1/16 W
Max. Operation
Voltage (DC or RMS) 200V 150V 50V 50V
Max. Overload
Voltage (DC or RMS) 400V 300V 100V 100V
Climatic category 55/155/56
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. The resistance of Jumper is defined <0.05Ω.
DIMENSIONS
(unit : mm)
WR12 WR08 WR06 WR04
L 3.10 ± 0.10
2.00 ± 0.10
1.60 ± 0.10
1.00 ± 0.05
W 1.60 ± 0.10
1.25 ± 0.10
0.80 ± 0.10
0.50 ± 0.05
T 0.60 ± 0.15
0.50 ± 0.15
0.45 ± 0.15
0.35 ± 0.05
Tb 0.45 ± 0.20
0.40 ± 0.20
0.30 ± 0.15
0.25 ± 0.10
Tt 0.50 ± 0.20
0.40 ± 0.20
0.30 ± 0.10
0.20 ± 0.10
Approval sheet
Page 4 of 9 ASC_WR_V21 Mar.- 2012
MARKING
Size \ Nr. Of digit of code\tolerance ±
±±
±5% ±
±±
±1%
1206 (3216) 3-digits marking 4-digits marking
0805 (2012) 3-digits marking 4-digits marking
0603 (1608) 3-digits marking 3-digits marking
0402(1005) N0 MARKING
3-digits marking（±5% : 1206 & 0805 & 0603 ）
Each resistor is marked with a three digits code on the protective coating to designate the nominal resistance value.
3-digits marking（±1% : 0603）
Nominal resistance Description
1.E-24 series As 0603 WR06X ±5%.
2.E-96 series The 1st two digit codes are referring to the CODE on the table, the 3rd code is the index of resistance
value :
Y=10
-2
，X=10
-1
，A=10
0
，B=10
1
，C=10
2
，D=10
3
，E=10
4
，F=10
5
EX : 17.8Ω=25X，178Ω=25A，1K78 =25B
17K8=25C， 178K=25D， 1M78=25E
3. Remark There is no marking for the items are not under E-24 and E-96 series
CODE
R_value
CODE
R_value
CODE
R_Value
CODE
R_value
CODE
R_value
CODE
R_value
CODE
R_value
CODE
R_value
01 100
13 133
25 178
37 237
49 316
61 422
73 562
85 750
02 102
14 137
26 182
38 243
50 324
62 432
74 576
86 768
03 105
15 140
27 187
39 249
51 332
63 442
75 590
87 787
04 107
16 143
28 191
40 255
52 340
64 453
76 604
88 806
05 110
17 147
29 196
41 261
53 348
65 464
77 619
89 825
06 113
18 150
30 200
42 267
54 357
66 475
78 634
90 845
07 115
19 154
31 205
43 274
55 365
67 487
79 649
91 866
08 118
20 158
32 210
44 280
56 374
68 499
80 665
92 887
09 121
21 162
33 215
45 287
57 383
69 511
81 681
93 909
10 124
22 165
34 221
46 294
58 392
70 523
82 698
94 931
11 127
23 169
35 226
47 301
59 402
71 536
83 715
95 953
12 130
24 174
36 232
48 309
60 412
72 549
84 732
96 976
4-digits marking（
±1% : 1206/0805
）
Each resistor is marked with a four digits code on the protective coating to designate the nominal resistance value.
Example
RESISTANCE 10Ω 12Ω 100Ω 6800Ω 47000Ω
3-digits marking（
（（
（1206 & 0805 & 0603 ±
±±
±5% ）
））
） 100 120 101 682 473
4-digits marking 10R0 12R0 1000 6801 4702
Approval sheet
Page 5 of 9 ASC_WR_V21 Mar.- 2012
FUNCTIONAL DESCRIPTION
Product characterization
Standard values of nominal resistance are taken from the E24 series for resistors with a tolerance of ±5%,
and E96 series for resistors with a tolerance of ±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 for WR12, WR08,
WR06, WR04
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.
Approval sheet
Page 6 of 9 ASC_WR_V21 Mar.- 2012
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
WR12 X 472_ J T L
Size code
WR12 : 1206
WR08 : 0805
WR06 : 0603
WR04: 0402
Type code
X :
±5%, 1Ω ~ 10MΩ
±1%, 10Ω ~ 1MΩ
W :
±1%, < 10Ω; >1MΩ
Resistance code
±5%, E24: 2 significant
digits followed by no. of
zeros and a blank
4.7Ω =4R7_
10Ω =100_
220Ω =221_
Jumper =000_
(“_” means a blank)
±1%, E24+E96: 3 significant
digits followed by no. of
zeros
102Ω =1020
37.4KΩ =3742
Tolerance
F : ±1%
J : ±5%
P : Jumper
Packaging code
T : 7” Reeled taping
Q : 10” Reeled taping
G : 13” Reeled taping
H : 13'' reel 50Kpcs
only for 0402
B : Bulk
D : 7'' reel 20Kpcs
only for 0402
A : 7" reel 15Kpcs only
for 0402
Termination code
L= Sn base
(lead free)
WR12, WR08, WR06:
1. Reeled tape packaging : 8mm width paper taping 5000pcs per 7” reel, 10kpcs per 10” reel, 20kpcs per 13” reel.
2. Bulk packaging : 5000pcs per poly-bag
WR04:
1. Reeled tape packaging : 8mm width paper taping 10,000pcs per reel,
2. Bulk packaging : 10,000pcs per poly-bag
Approval sheet
Page 7 of 9 ASC_WR_V21 Mar.- 2012
TEST AND REQUIREMENTS
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.
REQUIREMENT
TEST PROCEDURE / TEST METHOD Resistor 0Ω
ΩΩ
Ω
Electrical
Characteristics
JISC5201-1: 1998
Clause 4.8
-
DC resistance values measurement
-
Temperature Coefficient of Resistance (T.C.R)
Natural resistance change per change in degree centigrade.
( )
6
121
12 10×
−
−
ttR RR
(ppm/°C) t
1
: 20°C+5°C-1°C
R
1
: Resistance at reference temperature (20°C+5°C/-1 °C)
R
2
: Resistance at test temperature (-55°C or +155°C)
Within the specified tolerance
Refer to “QUICK REFERENCE
DATA”
<50mΩ
Resistance to
soldering heat(R.S.H)
JISC5201-1:1998
Clause 4.18
Un-mounted chips completely immersed for 10±1second in a SAC
solder bath at 260℃±5ºC
±5%:∆R/Rmax.±(1%+0.05Ω)
±1%:∆R/Rmax.±(0.5%+0.05Ω)
no visible damage <50mΩ
Solderability
JISC5201-1: 1998
Clause 4.17
Un-mounted chips completely immersed for 2±0.5 second in a SAC
solder bath at 235℃±5℃ 95% coverage min., good tinning and no
visible damage
Temperature cycling
JISC5201-1: 1998
Clause 4.19
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
±5%: ∆R/R max. ±(1%+0.05Ω)
±1%:∆R/Rmax.±(0.5%+0.05Ω)
No visible damage
<50mΩ
High Temperature
Exposure
MIL-STD-202
method 108
1000+48/-0 hours; without load in a temperature chamber
controlled 155±3°C
±5%:∆R/Rmax.±(2%+0.1Ω)
±1%:∆R/Rmax.±(1%+0.1Ω)
No visible damage <50mΩ
Bending strength
JISC5201-1: 1998
Clause 4.33
Resistors mounted on a 90mm glass epoxy resin PCB(FR4), bending
once 3mm for 10sec, 5mm for WR04
±5%:∆R/Rmax.±(1%+0.05Ω)
±1%:∆R/Rmax.±(1%+0.05Ω)
No visual damaged <50mΩ
Adhesion
JISC5201-1: 1998
Clause 4.32
Pressurizing force: 5N, Test time: 10±1sec.
No remarkable damage or removal of the
terminations
Short Time Overload
(STOL)
JISC5201-1: 1998
Clause 4.13
2.5 times RCWV or max. overload voltage, for 5seconds
±5%: ∆R/R max. ±(2%+0.05Ω)
±1%: ∆R/R max. ±(1%+0.05Ω)
No visible damage <50mΩ
Approval sheet
Page 8 of 9 ASC_WR_V21 Mar.- 2012
REQUIREMENT
TEST PROCEDURE / TEST METHOD Resistor 0Ω
ΩΩ
Ω
Load life in Humidity
JISC5201-1: 1998
Clause 4.24
1000 +48/-0 hours, loaded with RCWV or Vmax in humidity chamber
controller at 40°C±2°C and 90~95% relative humidity, 1.5hours on and
0.5 hours off
±5%: ∆R/R max. ±(2%+0.1Ω)
±1%: ∆R/R max. ±(1%+0.1Ω)
No visible damage <50mΩ
Load life (endurance)
JISC5201-1: 1998
Clause 4.25
1000 +48/-0 hours, loaded with RCWV or Vmax
in chamber controller
70±2ºC, 1.5 hours on and 0.5 hours off
±5%: ∆R/R max. ±(3%+0.1Ω)
±1%: ∆R/R max. ±(1%+0.1Ω)
No visible damage <50mΩ
Insulation Resistance
JISC5201-1: 1998
Clause 4.6
Apply the maximum overload voltage (DC) for 1minute
R≧10GΩ
Dielectric Withstand
Voltage
JISC5201-1: 1998
Clause 4.7
Apply the maximum overload voltage (AC) for 1 minute
No breakdown or flashover
TEST CONDITION FOR JUMPER (0 Ω
ΩΩ
Ω)
Item WR12 WR08 WR06 WR04
Power Rating At 70°C 1/4W 1/8W 1/10W 1/16W
Resistance MAX.50mΩ
Rated Current 2A 1.5A 1A 1A
Peak Current 5A 3.5A 3A 2A
Operating Temperature -55 ~ +155°C
Approval sheet
Page 9 of 9 ASC_WR_V21 Mar.- 2012
PACKAGING
Paper Tape specifications (unit :mm)
Series No. A B W F E
WR12 3.60±0.20 2.00±0.20
WR08 2.40±0.20 1.65±0.20
WR06 1.90±0.20 1.10±0.20
WR04 1.20±0.10 0.70±0.10
8.00±0.30 3.50±0.20 1.75±0.10
Series No. P1 P0 ΦD T
WR12 / WR08 Max. 1.0
WR06 4.00±0.10 0.65±0.05
WR04 2.00±0.10
4.00±0.10
1.0 0.0
50.1
+
−
Φ
0.40±0.05
7” Reel dimensions
Symbol A B C D
(unit : mm) Φ178.0±2.0 Φ60.0±1.0 13.0±0.2 9.0±0.5
