Document Number: 50035 For technical questions, contact: sfer@vishay.com www.vishay.com
Revision: 31-Mar-10 37
RTO 50
Vishay Sfernice
50 W Power Resistor, Thick Film Technology, TO-220
FEATURE
•50 W at 25 °C heatsink mounted
•Adjusted by sand trimming
•Leaded or surface mount versions
•High power to size ratio
•Non inductive element
•Compliant to RoHS directive 2002/95/EC
Because of the knowledge and experience in Thick Film technology, Vishay Sfernice has been able to develop a high power
resistor in a TO-220 package called RTO 50. The special design of this component allows the dissipation of 50 W when mounted
on a heatsink. The ohmic value is adjusted by sand trimming. This process does not generate hot spots as in laser trimming,
which could lead to microcracks on each side of the curve. This process improves the reliability and the stability of the resistor
and at the same time gives a good overload capability.
MECHANICAL SPECIFICATIONS
Mechanical Protection Molded
Resistive Element Thick film
Connections Tinned copper alloy
Weight 2.2 g max.
DIMENSIONS
Standard Package TO-220
Insulated case
ENVIRONMENTAL SPECIFICATIONS
Temperature Range - 55 °C to + 155 °C
Climatic Category 55/155/156
Sealing Sealed container
Solder immersion
Flammability IEC 60695-11-5
2 applications 30 s
seperated by 60 s
Note
• Not compatible with RoHS reflow profile
DIMENSIONS in millimeters
4.5
1.3
8.8
Ø 0.8
10.1
13.7
12.5
5.08
15
Ø 3.6
2.5
RTO 50F - LEADED
4.5
1.3
8.8
10.1
12.5
5.08
15
Ø 3.6
0.3
1.6
3
2
RTO 50C - FOR SURFACE MOUNTING
• Only for RTO 50 version C = during surface mount soldering, the
soldering temperature profile must not cause the metal tab of this
device to exceed 220 °C.
ELECTRICAL SPECIFICATIONS
Resistance Range 0.010 Ω to 550 kΩ serie E24
Tolerances Standard ± 1 % to ± 10 %
Dissipation and Associated Onto a heatsink
Thermal Resistance
and Nominal Power
50 W at + 25 °C
RTH (j - c): 2.6 °C/W
free air:
2.25 W at + 25 °C
Temperature Coefficient
Standard (- 55 °C; + 150 °C)
See Performance table
± 150 ppm/°C
Limiting Element Voltage UL300 V
Dielectric Strength
MIL STD 202 (301)
2000 VRMS - 1 min
10 mA max.
Insulation Resistance ≥ 106 MΩ
Inductance ≤ 0.1 µH
Critical Resistance 1.8 kΩ
www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50035
38 Revision: 31-Mar-10
RTO 50
Vishay Sfernice 50 W Power Resistor, Thick Film Technology, TO-220
CHOICE OF THE HEATSINK
The user must choose according to the working conditions of the component (power, room temperature).
Maximum working temperature must not exceed 155 °C. The dissipated power is simply calculated by the following ratio:
P: Expressed in W
ΔT: Difference between maximum working temperature and room temperature
RTH (j - c): Thermal resistance value measured between resistive layer and outer side of the resistor. It is the thermal
resistance of the component: (Special Features Table)
RTH (c - a): Thermal resistance value measured between outer side of the resistor and room temperature. It is the
thermal resistance of the heatsink itself (type, shape) and the quality of the fastening device
Example:
RTH (c - a): For RTO 50 power rating 13 W at ambient temperature + 30 °C
Thermal resistance RTH (j - c): 26 °C/W
Considering equation (1) we have:
ΔT ≤ 155 °C - 30 °C ≤ 125 °C
RTH (j - c) + RTH (c - a) = = = 9.6 °C/W
RTH (c - a) ≤ 9 .6 °C/W - 2.6 °C/W ≤ 7 °C/W
PERFORMANCE
TESTS CONDITIONS REQUIREMENTS
Momentary Overload
EN 60115-1
2 Pr 5 s for R < 2 Ω
1.6 Pr 5 s for R ≥ 2 Ω
US < 1.5 UL
± (0.25 % + 0.05 Ω)
Rapid Temperature Change
EN 60115-1
60 068-2-14
5 cycles - 55 °C to + 155 °C
± (0.5 % + 0.05 Ω)
Load Life EN 60115-1
Pr at + 25 °C, 1000 h CEI 115_1 ± (1 % + 0.05 Ω)
Humidity (Steady State) EN 60115-1
56 days RH 95 % ± (0.5 % + 0.05 Ω)
Vibration MIL STD 202
Method 204 C Test D ± (0.2 % + 0.05 Ω)
Terminal Strength MIL STD 202
Method 211 Test A1 ± (0.2 % + 0.05 Ω)
RESISTANCE VALUE IN RELATION TO TOLERANCE AND TCR
Resistance Values ≥ 0.01 Ω ≥ 0.015 Ω ≥ 0.1 Ω ≥ 0.5 Ω
Tolerances ± 1 % at ± 10 %
Temperature
Coefficient
(- 55 °C to + 155 °C)
Standard ± 900 ppm/°C ± 700 ppm/°C ± 250 ppm/°C ± 150 ppm/°C
PΔT
RTH (j - c) RTH (c - a)
+[]
----------------------------------------------------------1()
=
ΔT
P
------- 125
13
----------
Document Number: 50035 For technical questions, contact: sfer@vishay.com www.vishay.com
Revision: 31-Mar-10 39
RTO 50
50 W Power Resistor, Thick Film Technology, TO-220 Vishay Sfernice
OVERLOADS
The applied voltage must always be lower than the maximum
overload voltage of 450 V.
The values indicated on the graph below are applicable to
resistors in air or mounted onto a heatsink.
MARKING
Model, style, resistance value (in Ω), tolerance (in %),
manufacturing date, Vishay Sfernice trademark.
POWER RATING
The temperature of the heatsink should be maintained within
the limits specified.
To improve the thermal conductivity, surfaces in contact
should be coated with a silicone grease and the torque
applied on the screw for tightening should be around 1 Nm.
0.01
0.1
1
10
ENERGY CURVE
10-6 10-4
10-5 10-3 10-2
OVERLOAD DURATION IN s
ENERGY IN J
10-7 10-1
100
PACK AGI NG
Tube of 50 units
80
60
40
20
0
RATED POWER IN %
HEATSINK TEMPERATURE IN °C
0
100
20050 100 15025
ORDERING INFORMATION
RTO 50 F 100K ± 1%XXX TU50 e1
MODEL STYLE CONNECTIONS
F: Radial leads
C: Surface mount
RESISTANCE VALUE TOLERANCE
± 1%
± 2%
± 5%
± 10%
CUSTOM DESIGN
Optional
on request:
Special TCR,
shap, etc.
PACKAGING LEAD (Pb)-FREE
GLOBAL PART NUMBER INFORMATION
GLOBAL
MODEL SIZE LEADS OHMIC VALUE TOLERANCE PACKAGING
RTO 050 F = Radial leads
C = Surface mount
The first four digits are
significant figures and the last
digit specifies the number of
zeros to follow.
R designates decimal point.
48R70 = 48.7 Ω
48701 = 48 700 Ω
10002 = 100 000 Ω
R0100 = 0.01 Ω
R6800 = 0.68 Ω
27000 = 2700 Ω = 2.7 kΩ
F = 1 %
G = 2 %
J = 5 %
K = 10 %
T = Tube
Size 30 and 50:
Tube 50 pieces
050FR680T1T OR 0JE
Document Number: 91000 www.vishay.com
Revision: 18-Jul-08 1
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