Low Value 3W
Chip Resistors
LRF3W Series
Welwyn Components
•
•
•
3 Watts @ 70°C
Resistance range from 0.003 to 0.1Ω
Tolerances to ±1%
Electrical Data
Characteristic
Power dissipation @70°C
Resistance Range
Dielectric withstand
Ambient temp range
Resistance tolerance
TCR
Pad & trace area for maximum
power rating*
Value
3 Watts
0.005 to 0.100Ω
200V
-55 to +150°C
≤R005
5%, >R005 2, 5%,
≥R01
1, 2, 5%
±100ppm/°C
300mm
2
Power Derating Curve
100
% Of Power Rating
80
60
40
20
0
25°
70°
Temperature in
°C
150°
Physical Data
Top
Bottom
(Board Side)
0.81
±
0.13mm
Recommended
Solder Pad Layout
0.51
±
0.13mm
Plating
wrap-around
6.35
±
0.13mm
2.29
±
0.13mm
7.6mm
2mm
1mm
0.94 mm max
thickness
3.18
±
0.13mm
Weight 0.065g typ.
General Note
Welwyn Components reserves the right to make changes in product specification without notice or liability.
All information is subject to Welwyn’s own data and is considered accurate at time of going to print.
A subsidiary of
TT electronics plc
Issue D · 07.06
© Welwyn Components Limited
· Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
84
Low Value 3W
Chip Resistors
LRF3W Series
Construction
Patented non-noble copper based thick film material,
overglaze and organic protection are screen printed on a 96%
alumina substrate. The components are laser trimmed to
achieve the required resistance tolerance.
Welwyn Components
Chips can withstand immersion in solder at 250°C for
90 seconds and are suitable for reflow or wave soldering
mounting applications.
Marking
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
Chips are packed and mounted with marking side up.
The LRF3W Chips are mounted with the actual resistor
element mounted face down on its termination pads.
Terminations
The wrap-around terminations have an electroplated nickel
barrier and matte tin finish, this ensures excellent ‘leach’
resistance properties and solderability.
Performance Data
Typical
Load at rated power:
1000 hours at 70°C MIL-PRF-55342
Overload:
6.25 x rated power for 2 seconds MIL-PRF-55342
High temperature exposure:
MIL-PRF-55342
Low temperature operation:
MIL-PRF-55342
Low temperature storage:
-65°C, 100 hours
Moisture:
MIL-PRF-55342
Temperature cycling:
MIL-STD-883 Method 1010 Test condition B
Thermal shock:
MIL-STD-202 Method 107 condition B -65°C +125°C
Resistance to solder heat:
MIL-STD-202 Method 210
Shelf life test:
12 months at room temperature
Leach resistance:
molten solder 250°C
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
∆R%
1
0.5
0.5
0.5
0.5
0.5
0.25
0.25
0.25
0.1
90 Seconds min.
Packaging
LRF3W Resistors are supplied taped and reeled as per IEC 286-3. The standard quantity per reel is 1800 parts.
T
2
D
0
P
2
P
0
T
Marking
(Both sides)
33
±
1.0
13
±
0.5mm
E
F
13
±
0.5
178
±
2
80
±
2
B
0
2.5
±
0.5
0.8
±
0.15
T
1
K
0
A
0
P
1
D
1
Tape dimensions in mm
LRF3W
W
±0.3
12
P1
±0.1
8
P0
±0.1
4
P2
±0.05
2
D0
±0.1
1.5
D1
±0.2
1.5
E
±0.1
1.75
F
±0.05
5.5
A0
±0.1
3.61
B0
±0.1
6.96
K0
±0.1
1.17
T
±0.05
0.28
T1
nom
0.06
G
T2
±0.15
1.45
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
Issue D · 07.06
W
85
Low Value 3W
Chip Resistors
LRF3W Series
Welwyn Components
Ordering Procedure
Specify type reference, value and tolerance as shown in this example of LRF3W 5mΩ 2%:
Type
Resistance value
(IEC62 code)
Tolerance
(IEC62 code)
F
G
J
1%
2%
5%
LRF3W
R005
G
© Welwyn Components Limited
Bedlington, Northumberland NE22 7AA, UK
Telephone: +44 (0) 1670 822181 · Facsimile: +44 (0) 1670 829465 · Email: info@welwyn-tt.com · Website: www.welwyn-tt.com
86
Issue D · 07.06
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