LTO100 datasheet(3/6 Pages) VISHAY

3 / 6 page

LTO 100

www.vishay.com

Vishay Sfernice

Revision: 08-Dec-2021

Document Number: 50051

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

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:

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 - 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.

RTH (h - a): Thermal resistance of the heatsink.

Example:

RTH (c - h) + RTH (h - 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 - h) + RTH (h - a) =

= 15 °C/W

RTH (c - h) + RTH (h - 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.

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.

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.

P =

ΔT

TH (j - c)

[]

TH (c - h)

[]

TH (h - a)

[]

-----------------------------------------------------------------------------------

()

ΔT

-------

150

-----------

100

1000

10000

100

125

20406080

100

120

140

160

180

Axis Title

Case Temperature (°C)

175

LTO100 Datasheet(PDF) 3 Page - Vishay Siliconix

LTO100 Datasheet(HTML) 3 Page - Vishay Siliconix

Html Pages

1 2 3 4 5 6

Datasheet Download

Link URL