LTO100 - Vishay Presicion Group - Datasheet.Directory

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30 W, 50 W, and 100 W Power Resistor Thick Film Technology

LTO 30, LTO 50, LTO 100

VishaySfernice

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VMN-PT9158-1007

Revision29-Jul-09

www.vishay.com For technical questions, contact: sfer@vishay.com Document Number: 50049

74 Revision: 29-Jul-09

LTO 30, LTO 50, LTO 100

Vishay Sfernice

30 W 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

•30 W, 50 W, and 100 W at 25 °C case

temperature heatsink mounted

•Direct mounting ceramic on heatsink

•Broad resistance range: 0.010 Ω to 1 MΩ

•Non-inductive

•TO-220 and TO-247 package: Compact and easy to mount

•Compliant to RoHS directive 2002/95/EC

Note

• Tolerances unless stated: ± 0.3 mm

MECHANICAL SPECIFICATIONS

Mechanical Protection Molded

Resistive Element Thick film

Substrate Alumina

Connections Tinned copper

Weight 2 g max. (3.5 gfor LTO 100)

Mounting Torqure 1 Nm

DIMENSIONS

Standard Package TO-220, TO-247 isolated case

ENVIRONMENTAL SPECIFICATIONS

Temperature Range - 55 °C to + 155 °C

(- 55 °C to + 175 °C for LTO 100)

Climatic Category 55/155/56

Flammability IEC 60695-11-5

2 applications 30 s

separated by 60 s

DIMENSIONS in millimeters

LTO 30, LTO 50 LTO 100

3.2

16.2

10.4

1.8

5.08

0.6

3.5

1.3

0.8 12.7

3.2

Ø 3.2

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 0.010 Ω to 1 MΩ

Tolerances (Standard) ± 1 % to ± 10 %

Dissipation and Associated Onto a heatsink

Power Rating and

Thermal Resistance

of the Component

30 W, 50 W, and 100 W

at + 25 °C (case temp.)

RTH (j - c): 4.2 °C/W,

2.5 °C/W, 1.5 °C/W

Free air: 2.25 W, 2.5 W,

3.5 W at + 25 °C

Temperature Coefficient ± 150ppm/°C, ± 250 ppm/°C,

± 700 ppm/°C, ± 900 ppm/°C

Standard ± 150 ppm/°C

Limiting Element Voltage UL250 V, 375 V (for LTO 100)

Dielectric Strength

MIL STD 202

1500 VRMS - 1 min

10 mA max.

Insulation Resistance ≥ 104 MΩ

Inductance ≤ 0.1 µH

Critical Resistance 2.08 kΩ, 1.25 kΩ, 1.41 kΩ

Document Number: 50049 For technical questions, contact: sfer@vishay.com www.vishay.com

Revision: 29-Jul-09 75

LTO 30, LTO 50, LTO 100

30 W Power Resistor Thick Film Technology Vishay Sfernice

OVERLOADS

In any case the applied voltage must be lower than the

maximum overload voltage of 375 V (560 V for LTO 100).

The values indicated on the graph below are applicable to

resistors in air or mounted onto a heatsink.

ENERGY CURVE

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.

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:

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 30 power rating 10 W at ambient temperature + 25 °C

Thermal resistance RTH (j - c): 4.2 °C/W

Considering equation (1) we have:

ΔT = 150 °C - 25 °C = 125 °C

RTH (j - c) + RTH (c - a) = = = 12.5 °C/W

RTH (c - a) = 12.5 °C/W - 4.2 °C/W = 8.3 °C/W

with a thermal grease RTH (c - h) = 1 °C/W, we need a heatsink with RTH (h - a) = 7.3 °C/W.

10-6

ENERGY IN J

OVERLOAD DURATION IN s

100

0.1

0.01 10-5 10-4 10-3 10-2 10-1

LTO 30, LTO 50

LTO 100

RATED POWER IN %

CASE TEMPERATURE IN °C

125

100

0175

LTO 30, LTO 50 LTO 100

150125100755025

GLOBAL PART NUMBER INFORMATION

GLOBAL

MODEL SIZE LEADS OHMIC VALUE TOLERANCE PACKAGING LEAD (Pb)-FREE

LTO 030

050

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

(50 pieces for

LTO 100)

E3 = Pure tin

P = ΔT

RTH (j - c) + RT H (c - a)

[ ]

----------------------------------------------------------- 1( )

-------

125

---------

0 3 0 F 2 7 0 0 T 3T OL 0 J E

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