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
DESIGN SUPPORT TOOLS
Models
Available
click logo to get started
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 Torque
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
Revision: 16-Nov-17
-55 °C to +150 °C
55 / 155 / 56
IEC 60695-11-5
2 applications 30 s
separated by 60 s
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
= 150 °C - 25 °C = 125 °C
T
P
125
10
R
TH (j - c)
+ R
TH (c - h)
+ R
TH (h - a)
=
-----
=
-------
= 12.5 °C/W
-
-
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: 16-Nov-17
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: 16-Nov-17
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
RELATED DOCUMENTS
APPLICATION NOTES
Potentiometers and Trimmers
Guidelines for Vishay Sfernice Resistive and Inductive Components
www.vishay.com/doc?51001
www.vishay.com/doc?52029
Revision: 16-Nov-17
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
ALL PRODUCT, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE TO IMPROVE
RELIABILITY, FUNCTION OR DESIGN OR OTHERWISE.
Vishay Intertechnology, Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively,
“Vishay”), disclaim any and all liability for any errors, inaccuracies or incompleteness contained in any datasheet or in any other
disclosure relating to any product.
Vishay makes no warranty, representation or guarantee regarding the suitability of the products for any particular purpose or
the continuing production of any product. To the maximum extent permitted by applicable law, Vishay disclaims (i) any and all
liability arising out of the application or use of any product, (ii) any and all liability, including without limitation special,
consequential or incidental damages, and (iii) any and all implied warranties, including warranties of fitness for particular
purpose, non-infringement and merchantability.
Statements regarding the suitability of products for certain types of applications are based on Vishay’s knowledge of
typical requirements that are often placed on Vishay products in generic applications. Such statements are not binding
statements about the suitability of products for a particular application. It is the customer’s responsibility to validate that a
particular 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
technical experts. Product specifications do not expand or otherwise modify Vishay’s terms and conditions of purchase,
including but not limited to the warranty expressed therein.
Except as expressly indicated in writing, Vishay products are not designed for use in medical, life-saving, or life-sustaining
applications or for any other application in which the failure of the Vishay product could result in personal injury or death.
Customers using or selling Vishay products not expressly indicated for use in such applications do so at their own risk.
Please contact authorized Vishay personnel to obtain written terms and conditions regarding products designed for
such applications.
No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted by this document
or by any conduct of Vishay. Product names and markings noted herein may be trademarks of their respective owners.
© 2017 VISHAY INTERTECHNOLOGY, INC. ALL RIGHTS RESERVED
Revision: 08-Feb-17
1
Document Number: 91000
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