Power Metal Oxide
Film Resistors
MO-S Series
Welwyn Components
•
•
•
Small size for power rating
Can replace carbon composition in many
pulse handling applications
Flameproof protection
Electrical Data
Power rating at 70°C
Restance range
Limiting element voltage
TCR
Isolation voltage
Resistance tolerance
Standard values
Thermal impedance
Ambient temperature range
watts
ohms
volts
ppm/°C
volts
%
°C/watt
°C
MO
1
/
2
S
0.5
10R - 50K
250
350
MO1S
1.0
MO2S
2.0
10R - 100K
350
350
500
5, 10
E24 preferred
80
-55 to +155
MO3S
3.0
MO5S
5.0
10R - 100K
500
700
140
110
60
35
Physical Data
Dimensions (mm) and Weight (g)
pcb
mounting
centres
10.0
12.5
15.0
20.0
30.0
Min
bend
radius
0.6
1.2
1.2
1.2
1.2
Wt.
nom.
0.3
0.5
0.9
1.1
4.3
Type
L max.
1
/
2
S
MO
6.2
MO1S
9.0
MO2S
12.5
MO3S
14.5
MO5S
25.0
D max.
2.5
3.6
4.2
5.3
8.5
f min.
21.0
19.6
17.8
23.8
27.6
d nom.
0.6
0.8
0.8
0.8
0.8
d
D
L
f
Construction
The tin oxide resistance element is deposited onto a high
purity ceramic rod. End caps are force fitted and termination
wires are welded to the end caps. The element is adjusted to
the required resistance value by a helical cut; finally a cement
protection is applied to the resistor body prior to marking
with indelible ink.
Marking
MO
1
/
2
S, MO1S, MO2S and MO3S resistors are colour coded
with four bands. IEC 62 colours are used. For larger sizes type
reference, resistance value and tolerance are legend marked.
The resistance value marking conforms to lEC 62.
Solvent Resistance
The body protection and marking are resistant to all normal
industrial cleaning solvents suitable for printed circuits.
Terminations
Material
Resistor sizes up to and including the MO3S
use solder coated copper terminations. MO4S
and MO5S use solder coated steel cored
terminations.
The terminations meet the requirements of
IEC 68.2.21.
Flammability
The resistor coating will not burn or emit incandescent
particles under any condition of applied temperature or
power overload.
Strength
Solderability
The terminations meet the requirements of
IEC 115-1, Clause 4.17.3.2.
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 C · 07.04
© 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
149
Power Metal Oxide
Film Resistors
MO-S Series
Welwyn Components
Performance Data
Maximum
Load at rated power: 1000 hrs at 70°c
Shelf life: 12 months at room temperature
Derating
Climatic
Climatic category
Temperature rapid change
Resistance to solder heat
∆R%
∆R%
∆R%
∆R%
∆R%
5
2
See derating curve
1
40/125/56
0.5
0.5
Application Notes
% of Rated Power at 70°C
MO-S Series Derating Curve
100
90
80
70
60
50
40
30
20
10
0
60
80
100
120
140
160
180
200
220
240
1. If the resistors are to dissipate full rated power, it is
recommended that the terminations should not be
soldered closer than 4mm from the body.
2. Due to operating temperature limitations imposed by some
pcb materials, derating may be necessary. An estimate of
the temperature rise to be expected can be calculated
using the thermal impedance figures given under Electrical
Data.
3. MO-S resistors can also be supplied pre-formed.
See lead form section for details.
Ambient Temp
Figure 1
Packaging
Our standard packaging for MO
1
/
2
S, MO1S, MO2S and MO3S
is taped and ammo packed, MO5S is taped and reeled. The
critical dimensions are shown in Figure 1.
The component wires will not protrude beyond the outside
edge of the tapes.
Pre-formed resistors are supplied loose packed in plastic bags
or boxes.
Alternative packaging available by request.
6
c
f
1
b
f
2
6
Body Location f
1
– f
2
≤
1.4 mm
Type
b
c
MO
1
/
2
S
52
5
MO1S
52
5
MO2S
52
5
MO3S
67
10
MO5S
85
10
Standard Quantities Per Package
Type
Reel
Ammo pack
MO
1
/
2
S
5000
5000
MO1S
2500
2500
MO2S
2500
1500
MO3S
1000
1000
MO5S
700
n/a
© 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
150
Issue C · 07.04
FPGA/CPLD
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