www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50051
80 Revision: 27-Aug-10
LTO 100
Vishay Sfernice
Power Resistor Thick Film Technology
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.
FEATURE
•100 W at 25 °C case temperature heatsink
mounted
•Direct mounting ceramic on heatsink
•Broad resistance range: 0.015 Ω to 1 MΩ
•Non inductive
•TO-247 package: Compact and easy to mount
•Compliant to RoHS directive 2002/95/EC
Note
• Tolerance unless otherwise specified: ± 0.3 mm
MECHANICAL SPECIFICATIONS
Mechanical Protection Molded
Resistive Element Thick film
Substrate Alumina
Connections Tinned copper
Weight 3.5 g max.
Mounting Torqure 1 Nm
DIMENSIONS
Standard Package TO-247 isolated case
ENVIRONMENTAL SPECIFICATIONS
Temperature Range - 55 °C to + 175 °C
Climatic Category 55/175/56
Flammability IEC 60695-11-5
2 applications 30 s
separated by 60 s
DIMENSIONS in millimeters
5.0
20.7
15.76
2.4
10.16
0.6
3.5
3.6
1.5
14.5
Ø 3.6
5.33
ELECTRICAL SPECIFICATIONS
Resistance Range 0.015 Ω to 1 MΩ
Tolerances (Standard) ± 1 % to ± 10 %
Dissipation and Associated Onto a heatsink
Power Rating and
Thermal Resistance
of the Component
100 W at + 25 °C (case temp.)
RTH (j - c): 1.5 °C/W
Free air:
3.5 W at + 25 °C
Temperature Coefficient See Performance table
Standard ± 150 ppm/°C
Limiting Element Voltage UL375 V
Dielectric Strength
MIL STD 202
1500 VRMS - 1 min
10 mA max.
Insulation Resistance ≥ 104 MΩ
Inductance ≤ 0.1 µH
Critical Resistance 1.41 kΩ
Document Number: 50051 For technical questions, contact: sfer@vishay.com www.vishay.com
Revision: 27-Aug-10 81
LTO 100
Power Resistor Thick Film Technology Vishay Sfernice
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 175 °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.
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, and the thermal resistance
of the thermal compound.
Example:
RTH (c - a) for LTO 100 power rating 10 W at ambient temperature + 25 °C
Thermal resistance RTH (j - c): 1.5 °C/W
Considering equation (1) we have:
ΔT = 175 °C - 25 °C = 150 °C
RTH (j - c) + RTH (c - a) = = = 15 °C/W
RTH (c - a) = 15 °C/W - 1.5 °C/W = 13.5 °C/W
with a thermal grease RTH (c - h) = 1 °C/W, we need a heatsink with RTH (h - a) = 12.5 °C/W.
PERFORMANCE
TESTS CONDITIONS REQUIREMENTS
Momentary Overload
EN 60115-1
1.5 Pr/5 s
US < 1.5 UL
± (0.5 % + 0.005 Ω)
Rapid Temperature Change
EN 60115-1
IEC 60068-2-14 Test Na
5 cycles
- 55 °C to + 175 °C
± (0.5 % + 0.005 Ω)
Load Life EN 60115-1
1000 h Pr at + 25 °C ± (1 % + 0.005 Ω)
Humidity (Steady State) MIL STD 202
Method 103 B Cond. D ± (0.5 % + 0.005 Ω)
Vibration MIL STD 202
Method 204 Cond. D ± (0.2 % + 0.005 Ω)
Terminal Strength MIL STD 202
Method 211 Cond. A1 ± (0.2 % + 0.005 Ω)
Shock 100G, MIL STD 202
Method 213 Cond. I ± (0.5 % + 0.005 Ω)
SPECIAL FEATURES
Resistance Values ≥ 0.010 ≥ 0.015 ≥ 0.1 ≥ 0.5
Tolerances ± 1 % at ± 10 %
Typical Temperature Coefficient
(- 55 ° to + 175 °C) ± 900 ppm/°C ± 700 ppm/°C ± 250 ppm/°C ± 150 ppm/°C
P = ΔT
RTH (j - c) + RTH (c - a)
[]
----------------------------------------------------------- 1()
ΔT
P
-------
150
10
----------
www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50051
82 Revision: 27-Aug-10
LTO 100
Vishay Sfernice Power Resistor Thick Film Technology
OVERLOADS
In any case the applied voltage must be lower than the
maximum overload voltage of 560 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 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.
10-6
ENERGY IN J
OVERLOAD DURATION IN s
ENERGY CURVE
100
10
1
0.1
0.01 10-5 10-4 10-3 10-2 10-1
PACKAGING
Tube of 30 units
0 20 40 60 80 100 120 140 160 175
100
125
75
50
25
0
RATED POWER IN %
CASE TEMPERATURE IN °C
ORDERING INFORMATION
LTO 100 F 2.7 kΩ± 1 %xxx TU30 e3
MODEL STYLE CONNECTIONS RESISTANCE VALUE TOLERANCE
± 1 %
± 2 %
± 5 %
± 10 %
CUSTOM DESIGN
Optional
on request:
Special TCR,
shape etc.
PACKAGING LEAD (Pb)-FREE
GLOBAL PART NUMBER INFORMATION
GLOBAL
MODEL SIZE LEADS OHMIC VALUE TOLERANCE PACKAGING LEAD (Pb)-FREE
LTO 100 F = Radial leads 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
R4700 = 0.47 Ω
27000 = 2700 Ω = 2.7 kΩ
F = 1 %
G = 2 %
J = 5 %
K = 10 %
T = Tube
Tube 30 pieces
E3 = Pure tin
100F270 0 T 3T OL 0JE
Document Number: 91000 www.vishay.com
Revision: 18-Jul-08 1
Disclaimer
Legal Disclaimer Notice
Vishay
All product specifications and data are subject to change without notice.
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 herein
or in any other disclosure relating to any product.
Vishay disclaims any and all liability arising out of the use or application of any product described herein or of any
information provided herein to the maximum extent permitted by law. The product specifications do not expand or
otherwise modify Vishay’s terms and conditions of purchase, including but not limited to the warranty expressed
therein, which apply to these products.
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.
The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications unless
otherwise expressly indicated. Customers using or selling Vishay products not expressly indicated for use in such
applications do so entirely at their own risk and agree to fully indemnify Vishay for any damages arising or resulting
from such use or sale. Please contact authorized Vishay personnel to obtain written terms and conditions regarding
products designed for such applications.
Product names and markings noted herein may be trademarks of their respective owners.
