LTO 50
www.vishay.com
Vishay Sfernice
Power Resistor Thick Film Technology
FEATURES
• 50 W at 25 °C case temperature heatsink
mounted
• Direct mounting ceramic on heatsink
• Broad resistance range: 0.010
to 550 k
• Non inductive
• TO-220 package: Compact and easy to mount
• Material categorization: For definitions of compliance
please see
www.vishay.com/doc?99912
LTO series are the extension of RTO types. We used the
direct ceramic mounting design (no metal tab) of our RCH
power resistors applied to semiconductor packages.
DIMENSIONS
in millimeters
10.4
3.2
3.2
Ø 3.2
16.2
1.3
3.5
12.7
0.8
0.6
5 08
1.8
Note
• Tolerances unless stated: ± 0.3 mm
STANDARD ELECTRICAL SPECIFICATIONS
MODEL
LTO 50
SIZE
TO-220
RESISTANCE
RANGE
0.010 to 550K
RATED POWER LIMITING ELEMENT
TOLERANCE
P
25 °C
VOLTAGE U
L
±%
W
V
50
500
1, 2, 5, 10
TEMPERATURE
COEFFICIENT
± ppm/°C
150, 250, 700, 900
CRITICAL
RESISTANCE
5K
MECHANICAL SPECIFICATIONS
Mechanical Protection
Resistive Element
Substrate
Connections
Weight
Mounting Torqure
Molded
Thick film
Alumina
Tinned copper
2 g max.
1 Nm
TECHNICAL SPECIFICATIONS
Dissipation and Associated
Power Rating and
Thermal Resistance
of the Component
Temperature Coefficient
Standard
Dielectric Strength
MIL STD 202
Insulation Resistance
Inductance
Onto a heatsink
50 W at + 25 °C (case temp.)
R
TH (j - c)
: 2.5 °C/W
Free air:
2.5 W at + 25 °C
See Performance table
± 150 ppm/°C
1500 V
RMS
- 1 min
10 mA max.
10
4
M
0.1 μH
ENVIRONMENTAL SPECIFICATIONS
Temperature Range
Climatic Category
Flammability
- 55 °C to + 155 °C
55/155/56
IEC 60695-11-5
2 applications 30 s
separated by 60 s
Revision: 01-Aug-13
Document Number: 50050
1
For technical questions, contact:
sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT
www.vishay.com/doc?91000
LTO 50
www.vishay.com
Vishay Sfernice
CONDITIONS
EN 60115-1
1.5 Pr/5 s
U
S
< 1.5
U
L
EN 60115-1
IEC 60068-2-14 Test Na
5 cycles
- 55 °C to + 155 °C
EN 60115-1
1000 h Pr at + 25 °C
MIL-STD-202
method 103 B cond. D
MIL-STD-202
method 204 cond. D
MIL-STD-202
method 211 cond. A1
100G, MIL-STD-202
method 213 cond. I
REQUIREMENTS
± (0.5 % + 0.005
)
PERFORMANCE
TESTS
Momentary Overload
Rapid Temperature Change
± (0.5 % + 0.005
)
Load Life
Humidity (Steady State)
Vibration
Terminal Strength
Shock
± (1 % + 0.005
)
± (0.5 % + 0.005
)
± (0.2 % + 0.005
)
± (0.2 % + 0.005
)
± (0.5 % + 0.005
)
SPECIAL FEATURES
Resistance Values
Tolerances
Typical Temperature Coefficient
(- 55 ° to + 155 °C)
± 900 ppm/°C
0.010
0.015
± 1 % at ± 10 %
± 700 ppm/°C
± 250 ppm/°C
± 150 ppm/°C
0.1
0.5
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 150 °C. The dissipated power is simply calculated by the following ratio:
1
T
P =
-------------------------------------------------------------------------------------------
R
TH (j - c)
+ R
TH (c - h)
+ R
TH (h - a)
P: Expressed in W
T:
Difference between maximum working temperature and room
temperature
R
TH (j - c)
: Thermal resistance value measured between resistive layer
and outer side of the resistor. It is the thermal resistance of the
component.
R
TH (c - h)
: Thermal resistance value measured between outer side of
the resistor and upper side of the heatsink. This is the thermal
resistance of the interface (grease, thermal pad), and the quality of
the fastening device.
R
TH (h - a)
: Thermal resistance of the heatsink.
Example:
R
TH (c - a)
for LTO 50 power rating 10 W at ambient temperature + 25 °C
Thermal resistance R
TH (j - c)
: 2.5 °C/W
Considering equation
(1)
we have:
T
-
-------
-
R
TH (j - c)
+ R
TH (c - h)
+ R
TH (h - a)
=
-----
=
125
= 12.5 °C/W
P
10
T
= 150 °C - 25 °C = 125 °C
R
TH (c - h)
+ R
TH (h - a)
= 12.5 °C/W - 2.5 °C/W = 10 °C/W
with a thermal grease R
TH (c - h)
= 1 °C/W, we need a heatsink with R
TH (h - a)
= 9 °C/W.
Revision: 01-Aug-13
Document Number: 50050
2
For technical questions, contact:
sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT
www.vishay.com/doc?91000
LTO 50
www.vishay.com
OVERLOADS
In any case the applied voltage must be lower than the
maximum overload voltage of 750 V.
The values indicated on the graph below are applicable to
resistors in air or mounted onto a heatsink.
Vishay Sfernice
POWER RATING
The temperature of the case 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.
125
ENERGY CURVE
100
ENERGY IN JOULES
10
RATED POWER IN %
10
-6
10
-5
10
-4
10
-3
10
-2
10
-1
10
0
100
75
1
50
0.1
25
0.01
10
-7
OVERLOAD DURATION IN s
0
0
20
40
60
80
100
120
140 150
CASE TEMPERATURE IN °C
POWER CURVE
1 000 000
PACKAGING
100 000
Tube of 50 units
POWER IN W
MARKING
10 000
Model, style, resistance value (in
),
tolerance (in %),
manufacturing date, Vishay Sfernice trademark.
1000
100
10
-7
10
-6
10
-5
10
-4
10
-3
10
-2
10
-1
10
0
OVERLOAD DURATION IN s
Revision: 01-Aug-13
Document Number: 50050
3
For technical questions, contact:
sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT
www.vishay.com/doc?91000
LTO 50
www.vishay.com
Vishay Sfernice
2.7 k
RESISTANCE VALUE
±1%
TOLERANCE
±1%
±2%
±5%
± 10 %
xxx
CUSTOM DESIGN
Optional
on request:
Special TCR,
shape etc.
TU50
PACKAGING
e3
LEAD (Pb)-FREE
ORDERING INFORMATION
LTO
MODEL
50
STYLE
F
CONNECTIONS
GLOBAL PART NUMBER INFORMATION
L
T
O
0
5
0
F
2
7
0
0
0
J
T
E
3
GLOBAL
MODEL
LTO
SIZE
050
LEADS
F
= Radial leads
OHMIC VALUE
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
48701
= 48 700
10002
= 100 000
R0100
= 0.01
R4700
= 0.47
27000
= 2700
= 2.7 k
TOLERANCE
F
=1%
G
=2%
J
=5%
K
= 10 %
PACKAGING
T
= Tube
Tube 50 pieces
LEAD (Pb)-FREE
E3
= Pure tin
Revision: 01-Aug-13
Document Number: 50050
4
For technical questions, contact:
sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT
www.vishay.com/doc?91000
Legal Disclaimer Notice
www.vishay.com
Vishay
Disclaimer
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“Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained in any datasheet or in any other
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product with the properties described in the product specification is suitable for use in a particular application. Parameters
provided in datasheets and/or specifications may vary in different applications and performance may vary over time. All
operating parameters, including typical parameters, must be validated for each customer application by the customer’s
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Vishay Intertechnology, Inc. hereby certifies that all its products that are identified as RoHS-Compliant fulfill the
definitions and restrictions defined under Directive 2011/65/EU of The European Parliament and of the Council
of June 8, 2011 on the restriction of the use of certain hazardous substances in electrical and electronic equipment
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Please note that some Vishay documentation may still make reference to RoHS Directive 2002/95/EC. We confirm that
all the products identified as being compliant to Directive 2002/95/EC conform to Directive 2011/65/EU.
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Revision: 02-Oct-12
1
Document Number: 91000
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