CMFNON-MAGNETIC Datasheet, PDF (3/5 Pages) Vishay Siliconix – Metal Film Resistors, Non-Magnetic, Industrial, Precision

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CMF Non-Magnetic
Vishay Dale
TEMPERATURE COEFFICIENT CODES
GLOBAL TC CODE
HISTORICAL TC CODE
E
T-9
H
T-2
K
T-1
L
T-0
N
T-00
TEMPERATURE COEFFICIENT
25 ppm/°C
50 ppm/°C
100 ppm/°C
150 ppm/°C
200 ppm/°C
LOAD LIFE SHIFT DUE TO POWER AND DERATING (AT +70 °C AND AT +125 °C)
The power rating for the CMF parts is tied to the derating temperature, the heat rise of the parts, and the R for the load life performance.
When the tables/graphs below are used together they show that when the parts are run at their higher power ratings, the parts will run hotter,
which has the potential of causing the resistance of the parts to shift more over the life of the part.
LOAD LIFE SHIFT VS. POWER RATING
LOAD LIFE
± 0.15 %
MAXIMUM R (TYPICAL TEST LOTS)
± 0.5 %
± 1.0 %
± 0.15 %
± 0.5 %
± 1.0 %
MODEL
POWER RATING AT +70 °C
POWER RATING AT +125 °C
CMF50..143
1/20 W and 1/10 W
1/8 W
1/4 W
1/20 W
1/10 W
1/8 W
CMF55..143, CMF07..143 1/10 W and 1/8 W
1/4 W
1/2 W
1/10 W
1/8 W
1/4 W
CMF60..143, CMF20..143 1/8 W and 1/4 W
1/2 W
3/4 W and 1 W
1/8 W
1/4 W
1/2 W
CMF65..143
1/4 W and 1/2 W
3/4 W
1 W and 1-1/2 W
1/4 W
1/2 W
3/4 W and 1 W
CMF70..143
1/4 W and 1/2 W
3/4 W
1 W and 1-3/4 W
1/4 W
1/2 W 3/4 W and 1-1/4 W
CMF resistors have an operating temperature range of -55 °C to +175 °C.
They must be derated at high ambient temperatures according to the derating curve.
120
100
80
60
120
100
80
60
CCMMFF5550C....1M144F336, ^{0C.M.1F403C7C,M.C.MF1MF46F73520..0.1..14.14343,3}
40
40
20
20
0
- 55 - 50 - 25 0
DERATING
25 50 75 100
150 175 200
70
125
165
AMBIENT TEMPERATURE IN °C
0
0 0.125 0.25 0.375 0.5 0.625
THERMAL RESISTANCE
0.75 0.875 1 1.125
APPLIED POWER IN W
Example:
When a CMF55..143 part is run at 1/8 W in a 70 °C ambient environment, the resistor will generate enough heat that the surface temperature
of the part will reach about 19 °C over the ambient temperature, and over the life of the part this could cause the resistance value to shift up
to ± 0.15 %.
If the same resistor was instead run at 1/4 W in a 70 °C environment, the element will heat up to about 30 °C over ambient, and over the life
of the part the resistance value could shift roughly ± 0.5 %.
And if the resistor was run at it maximum power rating of 1/2 W in a 70 °C environment, it will heat up to about 58 °C over ambient, and you
could see the resistance value shift roughly ± 1 % over the life of the part.
MATERIAL SPECIFICATIONS
Element
Vacuum-deposited nickel-chrome alloy
Core
Fire-cleaned high purity ceramic
Coating
Solderability
Flame retardant epoxy, formulated for superior
moisture protection
Continuous satisfactory coverage when tested
in accordance with MIL-R-10509
Revision: 23-Apr-14
3
Document Number: 31091
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