High Power
Chip Resistors
SC3 Series
Welwyn Components
•
•
•
3 Watts in a 1 Watt size package*
Resistance range from 1 to 200
Tolerances to ±1%
* Rated Power @ 70˚C
Electrical Data
Characteristic
Power dissipation @70˚ C
Resistance Range
LEV
Ambient temp range
Resistance tolerance
TCR
Termination
Pad & trace area for maximum
power rating
Value
3 Watts
1.0 to 200
50V
-55 to +150˚C
1, 2, 5%
±100ppm/˚C
Leach-resistant solder-plated
copper wrap-around
300mm
2
Power Derating Curve
100
% Of Power Rating
80
60
40
20
0
25˚
70˚
Temperature in
˚C
150˚
Physical Data
Top
0.51
±
0.13mm
Bottom
(Board Side)
0.61
±
0.13mm
Recommended
Solder Pad Layout
Plating
wrap-around
6.35
±
0.13mm
2.29
±
0.13mm
7.6mm
2mm
1mm
0.762
±
0.127mm
thickness
3.18
±
0.13mm
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
B
03.02
Issue
A
· 01.07
© 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
High Power
Chip Resistors
SC3 Series
Construction
Resistive 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 SC3 Chips are mounted with the actual resistor element
mounted face down on its termination pads.
Terminations
The wrap-around terminations have an
have an electroplated
copper terminations
electroplated nickel
barrier
barrier and tin-lead solder
ensures
this ensures
nickel
and matte tin finish. This
coating,
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.
Temperature Rise vs Pad Area
1000
Temperature Rise (˚C)
Pulse Power Rating
100
100
Power (watts)
100mm
2
1 watt
10
10
1
300mm
2
Termination Pad Area (each end)
2 watt
3 watt
1000mm
2
0.1
1.0
Time (sec)
10.0
© 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 A 03.02
Issue B ·
·
01.07
85
High Power
Chip Resistors
SC3 Series
Welwyn Components
Packaging
LRF3W Resistors
supplied taped and reeled as
as
IEC 286-3. The standard quantity per reel is
is 1800 parts.
SC3 Resistors are
are supplied taped and reeled
per
per IEC 286-3. The standard quantity per reel
1800 parts.
T
2
D
0
P
2
P
0
T
Marking
(Both sides)
33
±
1.0
13
±
0.5mm
E
13
±
0.5
F
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
SC3
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
Ordering Procedure
Specify type reference etc. as shown in this example of
SC3 at 33
Type
Resistance value
(IEC62 code)
Tolerance
(IEC62 code)
F
G
J
1%
2%
5%
1%
SC3
-
33R
F
© 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 B ·
·
01.07
Issue A 03.02
W
T2
±0.15
1.45
